AC130MKII and Morel CAT408

[Ludo]

I've had the AC130MKII for a couple of years and finally got around to trying to do something with it, so I started working on a ported, 2-way system for my youngest sister's 30th B-Day next year. She has a small apartment with a 13' x 9' living room so a small tower would fit her needs nicely.

http://www.parts-express.com/pe/showdetl.cfm?Partnumber=296-404

http://www.parts-express.com/pe/showdetl.cfm?Partnumber=277-086

I've got the AC130MKII in a 14L test box (7" x 9.5" x 24") tuned to 50Hz for an F3 of 52Hz, teamed up with the Morel CAT408 1-1/8" dome tweeter and crossed over at 2.3kHz. The x-overs are 3d-order electrical with a good measure of eq to smooth out the bumpy response of these two drivers. There's still a bump at 800Hz which was helped by adding stuffing to the cabinet and lots of room/floor bounce ripples at low frequencies which go away when I take a nearfiled measurement.

The sound is very clear and natural for vocals, the bass is firm but slightly mild and the trebble is a touch on the bright side, which I hope to tone down a notch once the cloth grill is added.

Has anyone else used either of these two drivers? I'd be interested in seeing what kind of in-box frequency response you measured and what you used for the x-over for either driver if you're willing to share.

Any other suggestions are wellcome.

Thanks,
Louis

[Wolf]

I've had the AC130MKII for a couple of years and finally got around to trying to do something with it, so I started working on a ported, 2-way system for my youngest sister's 30th B-Day next year. She has a small apartment with a 13' x 9' living room so a small tower would fit her needs nicely.

http://www.parts-express.com/pe/showdetl.cfm?Partnumber=296-404

http://www.parts-express.com/pe/showdetl.cfm?Partnumber=277-086

I've got the AC130MKII in a 14L test box (7" x 9.5" x 24") tuned to 50Hz for an F3 of 52Hz, teamed up with the Morel CAT408 1-1/8" dome tweeter and crossed over at 2.3kHz. The x-overs are 3d-order electrical with a good measure of eq to smooth out the bumpy response of these two drivers. There's still a bump at 800Hz which was helped by adding stuffing to the cabinet and lots of room/floor bounce ripples at low frequencies which go away when I take a nearfiled measurement.

The sound is very clear and natural for vocals, the bass is firm but slightly mild and the trebble is a touch on the bright side, which I hope to tone down a notch once the cloth grill is added.

Has anyone else used either of these two drivers? I'd be interested in seeing what kind of in-box frequency response you measured and what you used for the x-over for either driver if you're willing to share.

Any other suggestions are wellcome.

Thanks,
Louis

I have MDT40's, and they are xover'd about 1700 Hz, but they get a bit picky with the knee-treatment at rolloff. Otherwise they sound pretty good that low with no indication of strain. Your 408's are essentially the same tweeter with a round face.
Later,
Wolf

[Ludo]

I have MDT40's, and they are xover'd about 1700 Hz, but they get a bit picky with the knee-treatment at rolloff. Otherwise they sound pretty good that low with no indication of strain. Your 408's are essentially the same tweeter with a round face.
Later,
Wolf

I played with crossing the CAT408 lower but found it sounding just a touch gritty unless the attenuation in the 1 to 1.5kHz range was greater than 20dB. I took some single tone HD distortion measurements (see attachment) and they seemed to correlate with what I was hearing so I opted for the higher XO point. Its probably a minor point and barely audible with both drivers playing simultaneously, due to masking.

Louis

[JustinG]

I've had the AC130MKII for a couple of years and finally got around to trying to do something with it, so I started working on a ported, 2-way system for my youngest sister's 30th B-Day next year. She has a small apartment with a 13' x 9' living room so a small tower would fit her needs nicely.

http://www.parts-express.com/pe/showdetl.cfm?Partnumber=296-404

http://www.parts-express.com/pe/showdetl.cfm?Partnumber=277-086

I've got the AC130MKII in a 14L test box (7" x 9.5" x 24") tuned to 50Hz for an F3 of 52Hz, teamed up with the Morel CAT408 1-1/8" dome tweeter and crossed over at 2.3kHz. The x-overs are 3d-order electrical with a good measure of eq to smooth out the bumpy response of these two drivers. There's still a bump at 800Hz which was helped by adding stuffing to the cabinet and lots of room/floor bounce ripples at low frequencies which go away when I take a nearfiled measurement.

The sound is very clear and natural for vocals, the bass is firm but slightly mild and the trebble is a touch on the bright side, which I hope to tone down a notch once the cloth grill is added.

Has anyone else used either of these two drivers? I'd be interested in seeing what kind of in-box frequency response you measured and what you used for the x-over for either driver if you're willing to share.

Any other suggestions are wellcome.

Thanks,
Louis

If you are using the published specs for the AC130MKII they are incorrect and the sensitivity is a few dB lower so that is why your bass might be "mild". I really need to get FR of this driver since the T/S specs are so far off. Below is what I got using the WT3 on a few of the drivers, I got 2 of them about 2-3 years ago and a few just recently and they all measure very close to the same.

Fs: 56.5 Hz
Re:7.46 Ohms
Le: .36 mH
Qms: 6.56
Qes: .604
Qts: .553
Vas: 10.04 liters
Mms = 8.24 grams

[Ludo]

If you are using the published specs for the AC130MKII they are incorrect and the sensitivity is a few dB lower so that is why your bass might be "mild". I really need to get FR of this driver since the T/S specs are so far off. Below is what I got using the WT3 on a few of the drivers, I got 2 of them about 2-3 years ago and a few just recently and they all measure very close to the same.

Fs: 56.5 Hz
Re:7.46 Ohms
Le: .36 mH
Qms: 6.56
Qes: .604
Qts: .553
Vas: 10.04 liters
Mms = 8.24 grams

Justin,

The TS parameters for my four units measure fairly close to yours but the Vas I'm getting is closer to 14L using the box method. I also bought these about 2 years ago so I am not sure what would account for the difference.

---------1-------- 2--------3--------4--------Ave
Fs-------57-------55-------54-------55-------55
Qms----- 4.9------ 4.6------ 4.9------ 4.7------ 4.8
Qes------0.54-----0.51-----0.51-----0.47-----0.51
Re-------6.4------6.5------ 6.6------ 6.5------ 6.5
Le-------0.46-----0.48-----0.45-----0.48-----0.47

Also, the freq. resp. in my 7" x 9.5' x 24", well stuffed, test box is the blue curve below; it is 1/3 octave smoothed. It looks pretty bad hence my overly complex x-over.

Louis

[Ludo]

Finally bought a new WT3; zapped my old one by accidentally hooking it up to an xo with an amp hooked up.

So would you guys recommend a 4 ohm capable amp for this one or can most 8 ohm amps handle this kind of impedance; dips down to about 3.7 ohms and 10 degrees capacitive at 1kHz?

Louis

[Ludo]

I connected the speaker to my Furman SP20A Amp, configured for bridged mode, and its not having any problems driving it at any volume. This Amp is rated for 8 ohm loads in bridged mode and when I've tried to use it with 4 ohm speakers in the past, it would start to intermittently shut down as the volume was increased.

That's encouraging :)

Louis

[romanbednarek]

Finally bought a new WT3; zapped my old one by accidentally hooking it up to an xo with an amp hooked up.

So would you guys recommend a 4 ohm capable amp for this one or can most 8 ohm amps handle this kind of impedance; dips down to about 3.7 ohms and 10 degrees capacitive at 1kHz?

Louis

Based on all of the two way speaker designs that I've done, it is very odd to see an impedance dip near the crossover point although most of my two way crossovers are much less complex in general. I think that the culprit in your case is the use of a series notch filter within the passband of the woofer and I think that this is pulling the impedance down due to the shunt to ground within a region that the amplifier isn't isolated by another series impedance (as is the case when using a series notch filter in the stopband since the components between the filter and the amp increase the impedance seen by the amp).

Personally I think that I would find it very frustrating to try to tweak a crossover as complex as yours by ear (there are just too many variables to work with). Now I know that not everybody tweaks crossovers the same way that I do but it seems like you are relying more on response plots to adjust your crossover than your ears but perhaps the drivers you are working with are very tough to work with when it comes to reaching a neutral presentation. I guess that if I was working on your crossover, I would simplify it a bit and then start tweaking by ear because it seems possible that some issues that you are mentioning could be due to tonal balance as others have suggested.

[Ludo]

Based on all of the two way speaker designs that I've done, it is very odd to see an impedance dip near the crossover point although most of my two way crossovers are much less complex in general. I think that the culprit in your case is the use of a series notch filter within the passband of the woofer and I think that this is pulling the impedance down due to the shunt to ground within a region that the amplifier isn't isolated by another series impedance (as is the case when using a series notch filter in the stopband since the components between the filter and the amp increase the impedance seen by the amp).

Personally I think that I would find it very frustrating to try to tweak a crossover as complex as yours by ear (there are just too many variables to work with). Now I know that not everybody tweaks crossovers the same way that I do but it seems like you are relying more on response plots to adjust your crossover than your ears but perhaps the drivers you are working with are very tough to work with when it comes to reaching a neutral presentation. I guess that if I was working on your crossover, I would simplify it a bit and then start tweaking by ear because it seems possible that some issues that you are mentioning could be due to tonal balance as others have suggested.

Roman,

Actually I do both response measurements and listening; probably more of the latter. I listen to about 30 songs that I am now very familiar with on a variety of speakers, and if I am not happy with the sound, then I try to tweak the measured response to dial the measured spectrum up or down in the offending frequency segment which may also involve looking at what is going on in the x-over stopband response and the distortion. Then I do an A/B comparison, and if the changes hold up, then I widen my music selection and listen some more. On the x-over above, I spent about 3 months doing this; I am not happy with the complexity, but I am pleased with the sound.

I could probably go back and try to implement that series notch using a different topology.

Louis

[romanbednarek]

Roman,

Actually I do both response measurements and listening; probably more of the latter. I listen to about 30 songs that I am now very familiar with on a variety of speakers, and if I am not happy with the sound, then I try to tweak the measured response to dial the measured spectrum up or down in the offending frequency segment which may also involve looking at what is going on in the x-over stopband response and the distortion. Then I do an A/B comparison, and if the changes hold up, then I widen my music selection and listen some more. On the x-over above, I spent about 3 months doing this; I am not happy with the complexity, but I am pleased with the sound.

I could probably go back and try to implement that series notch using a different topology.

Louis

I apologize for the criticism. Your procedure seems very similar to mine when it comes to crossover tweaking. I guess that I've always compromised a bit sooner with my crossover designs while you seem to go a bit deeper at taming each part of the response, but in the end it is the sound that matters (as you know). However, I don't hold the belief that too many crossover parts degrade the sound like some who strive for minimalist crossover approaches do (although I do look at the budget in terms of crossover parts cost relative to overall design cost which is more of a concern for a project that others might build in the future).

As a general rule, I tend to use (p)arallel notch filters in the (p)assband and (s)eries notch filters in the (s)topband.

[Ludo]

I apologize for the criticism. Your procedure seems very similar to mine when it comes to crossover tweaking. I guess that I've always compromised a bit sooner with my crossover designs while you seem to go a bit deeper at taming each part of the response, but in the end it is the sound that matters (as you know). However, I don't hold the belief that too many crossover parts degrade the sound like some who strive for minimalist crossover approaches do (although I do look at the budget in terms of crossover parts cost relative to overall design cost which is more of a concern for a project that others might build in the future).

Roman,

No need to appologize; I am relatively new to this fascinating hobby and always look forward to learning new things, even though I may not realize their significance when I first encounter new ideas and suggestions.

My current approach with x-overs is to do "whatever it takes" until I am happy with the sound. Unfortunately this drives up the complexity and cost, but since my builds are one-offs for family and friends, I am ok with that compromize. IMO that the contribution of xo components to signal degradation is at least one or more orders of magnitude below the degradation from the drivers themselves so I don't get too hung up by the number of parts, as long as they are reasonable quality, except for the loss in sensitivity that they may introduce.


As a general rule, I tend to use (p)arallel notch filters in the (p)assband and (s)eries notch filters in the (s)topband.

Agree with you in general; I'll take a closer look at an alternate way to shape the response without hurting the overall impedance (this is probably where a modeling program would be very beneficial). :)

Louis

[Ludo]

Cabinet construction is coming along slowly. Building the 3/4" roundover with pine quarter-rounds is turning out to be a lot more work than I thought because they are not cut vey accurately; lots of sanding will be needed to get the cabinet edges to allign with the roundover.

Next step is sanding and veneer.

Louis

[Wolf]

Cabinet construction is coming along slowly. Building the 3/4" roundover with pine quarter-rounds is turning out to be a lot more work than I thought because they are not cut vey accurately; lots of sanding will be needed to get the cabinet edges to allign with the roundover.

Next step is sanding and veneer.

Louis

So... They have 'junk in the trunk'??:D
Wolf

[Ludo]

So... They have 'junk in the trunk'??:D
Wolf

Yeah, I guess I never thought of the shape in those terms, but junk-in-the-trunk seems appropriate. My wife keeps commenting how she likes the shape.... lets leave it at that :o

Louis

[Ludo]

Started veneering the cabinets with the backs first, and unfortunately I decided to try epoxy rather than the more conventional glues. This stuff is really difficult to work with without a vaccum press. I am having to go back along the edges to touch up the glue where it did not adhere completely.

I may switch to contact cement or the heat glue for the front/sides.

Louis

[Æ]

Any other suggestions are welcome.

Thanks,
Louis

OK, my suggestion is get a new calendar. That one on the wall says 1987?


Keep up the good work, hope to hear them one day.

[Ludo]

OK, my suggestion is get a new calendar. That one on the wall says 1987?


Keep up the good work, hope to hear them one day.

I can't get rid of that calendar:eek: It was autographed by Kevin Schwantz at Willow Springs Raceway before he became famous, at least to roadracing fans.

I need to get this veneer done so that I can bring them to our next DIY meet in April.

Louis

[DoubleTap]

I am having to go back along the edges to touch up the glue where it did not adhere completely.

That's good practice anyway ... use a paintbrush and paint a glue line on the bottom side of the veneer where it meets the cabinet. You'll realize why when you start trimming the veneer, greatly reduces chips.

Cold press veneer glue is always the best option for flat panels. For irregular panels you need a vacuum bagger of course. But cold press for me has always given the most fool-proof results. The Heat Lock glue is nice, but I'm finding that it can be delicate. I've had a few panels bubble with it after putting on a water based poly finish.

[Ludo]

That's good practice anyway ... use a paintbrush and paint a glue line on the bottom side of the veneer where it meets the cabinet. You'll realize why when you start trimming the veneer, greatly reduces chips.

Cold press veneer glue is always the best option for flat panels. For irregular panels you need a vacuum bagger of course. But cold press for me has always given the most fool-proof results. The Heat Lock glue is nice, but I'm finding that it can be delicate. I've had a few panels bubble with it after putting on a water based poly finish.

I am painting a line of glue along the edge as you point out, and where I can lift it up a bit, I am pushing some glue between the cabinet and the veneer.

I veneered another curved cabinet using contact cement and I did not have any of these problems so this one feels like a step backwards for me.

I'll take a look at the cold press glue, but wouldn't that have similar application characteristics to epoxy?

Louis

[Ludo]

I kept moving forward with the epoxy and built a sling out of a rubber floor matt to hold the veneer against the sides and then used sheets of mdf for clamping the front and sides flat. Overall, it worked out ok with a few areas still needing some touch up. I still need to veneer the tops, but first I want to test the drivers and the x-over in the final cabinet, to make sure nothing needs to be adjusted.

But first I need to rest; this speaker building is hard work :o

Any suggestions on how to finish rosewood?
Is this one of those woods that needs to be oiled?

Louis

[Ludo]

Been listening to these since the weekend and initially had the 20L cabinet tuned to 40Hz for an F3 of 49Hz, but the bass sounded slightly flat for my liking so I cut down the port tube to retune the cabinet to 46Hz for an F3 of 45Hz, but the bass sounded a bit thick with just a hint of boominess. So next I will try an intermediate port length to retune the cabinet to 43Hz, also with an F3 of 45Hz. Hopefully this will be a good compromise; we're talking about +/-0.75" on the 2"D x 5"L port tube.

Otherwise, I am really liking the sound of this system (best I've built so far) and have ordered the final x-over parts.

No suggestions on how to finish Rosewood?
Might have to start a separate thread.

Louis

[Æ]

I can't get rid of that calendar:eek:

What did one calendar say to the other?

Hey good looking, how about a date!

[Ludo]

What did one calendar say to the other?

Hey good looking, how about a date!

Still stuck on the calendar :rolleyes:

Any ideas how best to finish Rosewood :confused:

Louis

[davepellegrene]

Here (http://antiquerestorers.com/Articles/SAL/oilwood.htm) is a link to three methods that go into pretty good detail. Also tells you not what to do.
Dave

[Ludo]

Here (http://antiquerestorers.com/Articles/SAL/oilwood.htm) is a link to three methods that go into pretty good detail. Also tells you not what to do.
Dave

Thanks Dave,

The shellac and wax technique (option #2) looks promising.

The veneer appears very dry to me in some spots, especially on close inspection. Does this need any kind of treatment or is it normal?

Also, I was thinking of staining the veneer to get a slightly reddish color. I presume the techniques described in the article you attached would still work?

Louis

[davepellegrene]

Thanks Dave,

The shellac and wax technique (option #2) looks promising.

The veneer appears very dry to me in some spots, especially on close inspection. Does this need any kind of treatment or is it normal?

Also, I was thinking of staining the veneer to get a slightly reddish color. I presume the techniques described in the article you attached would still work?

Louis

I am definitely not an expert with Rosewood or veneering. If the spots you describe feel rough or dry there may be a chance they would take stain darker. A couple of things come to mind to try. I have had better luck if I want the wood to take on a curtain tone, as you say a reddish tint, I will mix the stain in the finish instead of applying it directly to the wood. This helps eliminate shading. Another technique is to thin the shellac with alcohol and apply a coat before you stain. Then lightly sand and apply your stain. I would then seal the stain with another coat or so with shellac. Then do the wax treatment.
Don Parson recently had a thread using rosewood on a knife he made that had some good info on sealing and waxing technique's.

There is also "amber" shellac that might take on the look you are after. It may be a little to orange, but may be worth looking into.

I have Brazilian Cherry for a hardwood floor, which really isn't cherry, but it darkens when exposed to light just like what cherry does. So I would be careful with getting the Rosewood to dark because I would think it will also tend to darken with age.

Oh, if you mix stain with the shellac it would have to be alcohol based. You can use regular stain, I believe, if you put it directly on the wood and let it dry thoroughly before sealing. Penetrating stains can take 72 hours before drying completely.

I would do a separate thread and I bet you would get a lot of info and idea's. Bob Barkto is pretty sharp on this stuff.
Dave

[Ludo]

I am definitely not an expert with Rosewood or veneering. If the spots you describe feel rough or dry there may be a chance they would take stain darker. A couple of things come to mind to try. I have had better luck if I want the wood to take on a curtain tone, as you say a reddish tint, I will mix the stain in the finish instead of applying it directly to the wood. This helps eliminate shading. Another technique is to thin the shellac with alcohol and apply a coat before you stain. Then lightly sand and apply your stain. I would then seal the stain with another coat or so with shellac. Then do the wax treatment.
Don Parson recently had a thread using rosewood on a knife he made that had some good info on sealing and waxing technique's.

There is also "amber" shellac that might take on the look you are after. It may be a little to orange, but may be worth looking into.

I have Brazilian Cherry for a hardwood floor, which really isn't cherry, but it darkens when exposed to light just like what cherry does. So I would be careful with getting the Rosewood to dark because I would think it will also tend to darken with age.

Oh, if you mix stain with the shellac it would have to be alcohol based. You can use regular stain, I believe, if you put it directly on the wood and let it dry thoroughly before sealing. Penetrating stains can take 72 hours before drying completely.

I would do a separate thread and I bet you would get a lot of info and idea's. Bob Barkto is pretty sharp on this stuff.
Dave

Dave,

Thanks again for all the ideas and insights.

I looked up Don's knife thread and he used the following technique, "I sanded to 600, then buffed with three levels of compound and finished with a combination of beeswax and carnuba that was blended and sent to me." So basically is this option #3 in the link that you sent? What the heck is carnuba?

I'll definitely start a separate thread before I start the final finish which is still looking like a couple of weeks away after I veneer the tops, sand all the edges, and test the final x-overs.

Louis

[davepellegrene]

Dave,

Thanks again for all the ideas and insights.

I looked up Don's knife thread and he used the following technique, "I sanded to 600, then buffed with three levels of compound and finished with a combination of beeswax and carnuba that was blended and sent to me." So basically is this option #3 in the link that you sent? What the heck is carnuba?

I'll definitely start a separate thread before I start the final finish which is still looking like a couple of weeks away after I veneer the tops, sand all the edges, and test the final x-overs.

Louis

I thought there was more info, in that link, about sealing and waxing. Carnuba I believe is just a type of wax. I use Mequiars yellow carnuba wax on my boat. Its good stuff. As far as wax goes on wood I have always liked Min wax past wax. Here (http://www.amazon.com/Natural-Minwax-Paste-Finishing-Wax/dp/B001F2WT8I). I would think just an oil with wax is going to give you more of a natural look like nothing is on the wood but a slight sheen. If you seal with shellac then wax you will get a grain showing through, but still see a finish on the wood. With some finish on the wood you can get any sheen you want from flat to gloss, just by how fine you sand or steel wool the finish. Also the more coats of shellac you put on the less grain that will show and the more glass like it will look. You can build up with shellac pretty fast. If you don't want to much build up thinning the shellac will make it soak in and leave the grain show.
Dave

[Ludo]

I thought there was more info, in that link, about sealing and waxing. Carnuba I believe is just a type of wax. I use Mequiars yellow carnuba wax on my boat. Its good stuff. As far as wax goes on wood I have always liked Min wax past wax. Here (http://www.amazon.com/Natural-Minwax-Paste-Finishing-Wax/dp/B001F2WT8I). I would think just an oil with wax is going to give you more of a natural look like nothing is on the wood but a slight sheen. If you seal with shellac then wax you will get a grain showing through, but still see a finish on the wood. With some finish on the wood you can get any sheen you want from flat to gloss, just by how fine you sand or steel wool the finish. Also the more coats of shellac you put on the less grain that will show and the more glass like it will look. You can build up with shellac pretty fast. If you don't want to much build up thinning the shellac will make it soak in and leave the grain show.
Dave

Dave,

I am looking for as close to a flat, natural look as possible, except I'd like to try for a slightly redish color, and do want the grain to show through. I do no want a glassy look at all, but was thinking that the shellac would help protect the wood and stabilize the finish vs just wax. Once I give these to my younger sister, I don't expect her to ever have to reapply wax. I also heard hat shellac tends to yellow with age; is that really an issue?

Louis

[davepellegrene]

Dave,

I am looking for as close to a flat, natural look as possible, except I'd like to try for a slightly redish color, and do want the grain to show through. I do no want a glassy look at all, but was thinking that the shellac would help protect the wood and stabilize the finish vs just wax. Once I give these to my younger sister, I don't expect her to ever have to reapply wax. I also heard hat shellac tends to yellow with age; is that really an issue?Louis


I don't think you need to worry to much about yellowing. It sounds like you won't be building the shellac up that much. I would think the thicker the finish the more chance for it to yellow.
I would put on the first coat thinned down and see how that goes. If it comes out rough enough that a rag sticks to it when your wiping it I would sand with a 220 grit and apply another coat. If it feels fairly smooth I would sand with 400 grit then apply another coat. Shellac is going to dry shinny, so you could get a grey scott brite pad or triple #000 steel wool instead of #0000 so you don't shine them up. I prefer the scotch brite pads if you are not trying to bring out a shine. If you use steel wool make sure you do it before you put the drivers in. All the little pieces from the steel wool stick all over the drivers because of the magnets and are a real pain to get off.
As far as the red tint goes I can't really help you since I have not used Rosewood. I would try some sample pieces to see how it takes the stain. If it goes on to dark I would try mixing it with the finish. It really depends on how absorbent the wood is. You could apply the stain after the first coat of thinned down shellac if it is taking it to dark.
Hope you have some scraps to work with. Maybe the driver cut outs.
Dave

[Æ]

Still stuck on the calendar :rolleyes:

Any ideas how best to finish Rosewood :confused:

Louis

I'm very amateur (inexperienced) when it comes to fine finishes. My next pair of loudspeakers will have a sprayed on paint job.
I finished the hardwood frame of my little tube amp with Tung Oil. Natural and shiny.

[Ludo]

I don't think you need to worry to much about yellowing. It sounds like you won't be building the shellac up that much. I would think the thicker the finish the more chance for it to yellow.
I would put on the first coat thinned down and see how that goes. If it comes out rough enough that a rag sticks to it when your wiping it I would sand with a 220 grit and apply another coat. If it feels fairly smooth I would sand with 400 grit then apply another coat. Shellac is going to dry shinny, so you could get a grey scott brite pad or triple #000 steel wool instead of #0000 so you don't shine them up. I prefer the scotch brite pads if you are not trying to bring out a shine. If you use steel wool make sure you do it before you put the drivers in. All the little pieces from the steel wool stick all over the drivers because of the magnets and are a real pain to get off.
As far as the red tint goes I can't really help you since I have not used Rosewood. I would try some sample pieces to see how it takes the stain. If it goes on to dark I would try mixing it with the finish. It really depends on how absorbent the wood is. You could apply the stain after the first coat of thinned down shellac if it is taking it to dark.
Hope you have some scraps to work with. Maybe the driver cut outs.
Dave

Dave,

Yes I have lots of scraps to practice on so I can apply the shellac in steps as well as the sanding and buffing to make sure it has the desired look. I may skip the redish stain as the mellow brown of the rosewood is starting to grow on me.

Louis

[Ludo]

I'm very amateur (inexperienced) when it comes to fine finishes. My next pair of loudspeakers will have a sprayed on paint job.
I finished the hardwood frame of my little tube amp with Tung Oil. Natural and shiny.

Hey, you're more experienced than I am :) How did you know to use Tung Oil, and why is tongue misspelled?

Louis

[Æ]

Hey, you're more experienced than I am :) How did you know to use Tung Oil, and why is tongue misspelled?

Louis

I go to my local ACE hardware store, they are well stocked with every conceivable stain/finish etc. I buy what they recommend. Tung oil was very easy to use, almost idiot proof.
I spelled tung correctly. LOL

[Wolf]

So the finish was to your 'taste'? :D
Wolf

[Ludo]

So the finish was to your 'taste'? :D
Wolf

Still deciding on the finish; so far its either shellac or tung oil. I'll get started on that next week.

Making some progress though. Here are the x-over boards; yes I know, its a lot of parts, but then this was not intended to be a budget build. I split the woofer x-over onto two boards to make it easier to install in the enclosure.

Louis

[gowa]

Those are going to be beautiful.

[Ludo]

Those are going to be beautiful.

Thanks Gowa,

Just need to keep reminding myself to take my time :)

I'm off to Southen Lumber this morning to check out their Rosewood Stock for the pedastals and to get their input on finishing options.

Louis

[Æ]

Thanks Gowa,

Just need to keep reminding myself to take my time :)

I'm off to Southen Lumber this morning to check out their Rosewood Stock for the pedastals and to get their input on finishing options.

Louis

This is what my project looks like, the one I used Tung Oil to finish.
By the way, Tung Oil isn't oily, it dries to a hard finish. You apply as many coats as you like, one at a time. The finish builds up. Cleanup was very easy too.
The wood is Bubinga and Walnut. Hardwood, not veneer.

[bobbarkto]

If your rosewood is oily (good chance of that) I would use shellac.
Any finish with oil in it will likely not dry properly if applied to bare rosewood.
Finishes to avoid: varnish, tung oil, tung oil varnish, lacquer (yes, lacquer has oil as it's base), polyurethane, linseed oil, danish oil, spar varnish etc.

Shellac is the universal sealer/barrier coat. Almost anything can be applied over shellac, except straight oils and some hot finishes like auto urethanes and some lacquers.

To get more red, use a dye, preferably oil based or transtint.
Oil based dyes are dissolved in mineral sprits, etc. They are easy to work with and won't raise the grain or introduce excess moisture.

Alcohol based dyes dry too quickly to be applied by hand to any large surface. They can be added to your shellac. Dissolve in alcohol first.

It's tricky using a tinted shellac or other film forming finish. Any overlap or heavy areas show more color intensity, ie: streaks and blotches.
Best to tread lightly with the color and use more coats, but not too many or the finish will be too thick. You can thin shellac to almost nothing without worry.
It's a balancing act.

After coloring apply another coat or three or four of very thin shellac. Rub with a bit of gray scotchbrite or 0000 steel wool.
You might want to wax after that, maybe not.

The wax I sent Don was something special for tool handles. A mix of hard and soft waxes and oils designed to be fairly durable yet not too slippery.

Straight carnuba wax is hard, very hard. It also produces a high gloss sheen and feels more like a high gloss lacquer under the hand. Not what you describe for your desired result?
Beeswax just glows with a beautiful soft sheen, might be just right, but is soft and can be sticky if applied too thick and is not too durable by itself. The right blend can work pretty well in a variety of applications.


Still deciding on the finish; so far its either shellac or tung oil. I'll get started on that next week.

Louis

[bobbarkto]

Just a point of reference for those interested.

Tung oil is a pure oil pressed from the fruit (nuts) of the tung tree.
It is a drying oil, is very water resistant and dries very slowly. It has low abrasion resistance and a low MEE (moisture excluding effectiveness).
It is an additive in some high quality varnishes and some oil varnish blends that use it to benefit water resistance and can also be used to change the overall color characteristics of the blend.

The "tung oil" products you buy at Ace or HD are all oil varnish blends or wiping varnishes. Oddly enough none of them contain any tung oil! They are more than 60% mineral spirits with ~35% linseed oil and some resin like alkyd, soy and or one of the phenolics.

One common brand of varnish that does contain real tung oil is Waterlox. It's good stuff.


This is what my project looks like, the one I used Tung Oil to finish.
By the way, Tung Oil isn't oily, it dries to a hard finish. You apply as many coats as you like, one at a time. The finish builds up. Cleanup was very easy too.
The wood is Bubinga and Walnut. Hardwood, not veneer.

[Æ]

Just a point of reference for those interested.

Tung oil is a pure oil pressed from the fruit (nuts) of the tung tree.
It is a drying oil, is very water resistant and dries very slowly. It has low abrasion resistance and a low MEE (moisture excluding effectiveness).
It is an additive in some high quality varnishes and some oil varnish blends that use it to benefit water resistance and can also be used to change the overall color characteristics of the blend.

The "tung oil" products you buy at Ace or HD are all oil varnish blends or wiping varnishes. Oddly enough none of them contain any tung oil! They are more than 60% mineral spirits with ~35% linseed oil and some resin like alkyd, soy and or one of the phenolics.

One common brand of varnish that does contain real tung oil is Waterlox. It's good stuff.

Good information, good to know.
The brand I used is Minwax.
http://www.minwax.com/products/specialty_products/tung_oil_finish.html

[bobbarkto]

I've used it and like it.
It's one of the "faux tung oils". A blend of mineral spirits and varnish, aka a wiping varnish. Minwax does make a very good varnish, and they use it in a bewildering variety of mixtures and products.

Here's a tip, anytime the front label says Tung Oil, it ain't got none.
Seriously. No joke.

Of all the finishes I know of that do actually contain tung oil as an ingredient, none list it on the front label. Some will list it as an ingredient, on the back or side, in small print.

None, with the exception of pure tung oil, and then it will say "Pure Tung Oil" on the label and not much else. Somewhere it will give an analysis of the purity and whether or not it contains any additives. Mostly it's pure enough for human consumption.




Good information, good to know.
The brand I used is Minwax.
http://www.minwax.com/products/specialty_products/tung_oil_finish.html

[critofur]

Hey, you're more experienced than I am :) How did you know to use Tung Oil, and why is tongue misspelled?

Louis

If you want to stain, you can use pre-stain conditioner on the wood to assure more even coloring.

About the finish though, the best thing you could do is: test different finishes on scraps of veneer!

On nice rosewood veneer I would do either tung oil or hand rubbed poly. A small amount of gloss to the finish will let the colors really come out - without making it look like it's plastic instead of real wood.

[Ludo]

Guys, Thanks for all the detailed responses; there's clearly much to know about woodworking and finishing.

I am going to pass on trying to stain the rosewood because the natural color is actually very appealing.

I will pursue the shelac finish then. Bob any specific brand/type you would recommend. I have heard that shelac tends to yellow with age and want to minimize that.

Still not clear on which wax would be best. I would like something fairly durable but not too glossy.

I have plenty of scraps to test and practice on before finishing the actual cabinets.

Louis

[bobbarkto]

Shellac doesn't change color much over time.
It is however available in a wide range of amber tones, from an almost clear light yellow to very dark red amber.
Lacquer is the finish that has the reputation for yellowing over time.

I'd suggest "garnet" shellac. I find it works very well on darker red toned wood and will intensify and deepen the natural red color nicely.
Another alternative is amber or blonde, it won't change the color of the wood much, just mellow it a little. On rosewood it can bring out the lighter orange/yellow tones a bit while making the reds a littl brighter. (a cheap source for the lighter colored shellac is Zinser Seal Coat at hdw stores and home centers).

Garnet shellac is sold in powder/flake/lump form (chunks and lumps usually) that has to be dissolved in alcohol. It's very easy to do. Just put the dry shellac in a glass jar and add enough alcohol to completely cover it. Seal the jar and let it sit overnight. For the first hour or three you can give it a little shake to stir it up and hasten the solution. Next day it should be completely liquid. Now add enough alcohol to make it workable. If the lumps are hard you might need to mash them a bit as they soak. On rare occasion they can be stubborn.

The usual recipe is called the cut, expressed in pounds of shellac per gallon of alcohol. I'd start with about a 1lb cut. You can do 2oz. of shellac in a quart of alcohol or 1oz. in a pint.

Apply many coats and it will build as thick as you want in a very controlled manner. The first few coats will disappear, but soon it starts to build. Many coats can be applied in a short time. It dries very quickly.

I like to pad it on using what's called a tampon (no - not that kind).
Take a 6" or so square of white lint free cotton cloth, a t-shirt works great. In the center place another piece of the cloth that's been wadded up to about the size of a half-dollar, maybe 1" -2" diameter. Draw up the corners of the square around the wad and use a twist tie or string or something to tie it off. You want the tampon to be pretty firm,
Dip the tip of the tampon in the shellac and let it soak up as much shellac as it wants. On a piece of scrap start rubbing it in. You'll soon see how it works, how wet you want the tampon, etc. The idea is you gently squeeze out the shellac as you rub it in. I use a stright line motion much like brushing, but you need to actually apply a bit of pressure to work the shellac in and smooth it out. Doing it will tell you more than I can in a forum post. It's pretty easy. Just don't get in a hurry, let the finish build at an easy pace and you'll do fine.

You can get a wide variety of shellac at toolsforworkingwood.com, Highland Woodworking, Shellac.net, Woodcraft, and many other wood finish suppliers.

It sounds much more complicated than it is, but it's really an easy way to get a nice finish.

For wax, not much beats Johnsons Paste Wax. Cheap and attractive, not too shiny and fairly durable. Let your shellac dry a day or two and then wax. Rub in a thin coat, let dry and buff, by hand is usually sufficient but if you use a machine go easy and watch for excessive heat generation as shellac can melt at high temps.

Hope this helps!


Guys, Thanks for all the detailed responses; there's clearly much to know about woodworking and finishing.

I am going to pass on trying to stain the rosewood because the natural color is actually very appealing.

I will pursue the shelac finish then. Bob any specific brand/type you would recommend. I have heard that shelac tends to yellow with age and want to minimize that.

Still not clear on which wax would be best. I would like something fairly durable but not too glossy.

I have plenty of scraps to test and practice on before finishing the actual cabinets.

Louis

[Ludo]

....Hope this helps!

OH YEAH!

Bob,

You certainly make it sound easy. I'll try to find the garnet shelac locally, but if not I'll order it from one of the on-line shops you've listed above. The tampond method sounds like fun. I'll snap some photos of the test piece hopefully in a week or so.

Louis

[joeybutts]

Wow.....these are gorgeous. I'm done with gloss piano finishes.....time to go all wood.....

[bobbarkto]

Ah, you're in Sunnyvale.
You lucky dog!
You've got Japan Woodworker over in Palo Alto!
Plus a Woodcraft and The Sawdust Shop in Sunnyvale!
Should be all set to find what you need locally.
Have fun!!!

Here's a few more tidbits.
When you are applying the shellac, if it starts to build too much you can knock it back with some alcohol. Just use a tampon with alcohol alone and rub away any excess.
Also, don't be afraid to dip your shellac laden tampon in alcohol if you need more control, this will temporarily thin the mix during application.
Another thing, I just noticed the size of the enclosures, use a larger tampon than I suggested, but not on the practice piece, stay with the size I mentioned previously until you get a feel for it.

[Ludo]

Ah, you're in Sunnyvale.
You lucky dog!
You've got Japan Woodworker over in Palo Alto!
Plus a Woodcraft and The Sawdust Shop in Sunnyvale!
Should be all set to find what you need locally.
Have fun!!!

Here's a few more tidbits.
When you are applying the shellac, if it starts to build too much you can knock it back with some alcohol. Just use a tampon with alcohol alone and rub away any excess.
Also, don't be afraid to dip your shellac laden tampon in alcohol if you need more control, this will temporarily thin the mix during application.
Another thing, I just noticed the size of the enclosures, use a larger tampon than I suggested, but not on the practice piece, stay with the size I mentioned previously until you get a feel for it.

I stopped by Southern Lumber over the weekend to find a matching hardwood base for the Rosewood veneer and they did a nice job of cutting and planing a massive plank down to the right length and thickness. They also recommended I try this finish from Deft. I sprayed 4 very thin coats, with light sanding between on a test piece, and I like the satin finish, but wonder how uniformly I could manage to apply it on a larger surface?

So this morning I stopped by the Sawdust Shop, and Wow! they've got an impressive woodworking shop there that you can rent time at. Also, they showed me some of the Garnet Shellac and I wound up not buying it because it just looks too red and they wanted $30 for a fairly large bag. So I wound up buying a can of clear Zinser shellac and will experiment with that this week.

They also told me that the Deft finish is a lacquer and that they did not recommend it for oily woods like rosewood, but that perhaps I could try it over the shellac.

So I'll try to squeeze in some time to experiment in between doing the taxes this week and I'll post some pics.

Louis

[bobbarkto]

Sounds like a plan.

As for the Garnet shellac.. it is red, looks more red before you dissolve in alcohol and apply. But the "clear" Zinser stuff will still look good and does a nice job on rosewoods. I just prefer the deeper color of the garnet. Like you I don't like the price but it is what it is... $30.00 is about average going rate for a pound.

If you really like the lacquer you should apply shellac first.
Two caveats.
Apply two coats of shellac. Sand only hte first to remove any slight roughness. The second should be left unsanded. If you were to sand it there would be a good chance of exposing some unsealed wood and hence oil.

Another thing, as you had done, apply very light coats of lacquer, especially the first two or three. This will help prevent the solvents in the lacquer from softening the shellac too much and again exposing some oil. There is also the chance that the shellac can wrinkle under hte lacquer if applied too heavily.

Deft is a very easy lacquer. It sprays well and is easy to sand. Light coats and some sanding and you shouldn't really have any problems. If you get a run or drip just sand it out and spray again. It's really close to foolproof (famous last words :eek:).

Good luck and have fun!

[Ludo]

Ok, finally some progress with a few minutes here and there in between work overload and taxes.

I think I have the recipe down and am happy with the color and texture of the finish. Two coats of shellac that's mixed 50/50 with alcohol followed by sanding with steel wool following the first coat. Then two coats of the spray finish, again followed by sanding with steel wool following the first coat. The Deft finish is actually a waterborne acrylic (says so right on the can), so I am not sure why the sales person said it was a lacquer?

The test piece marked with the blue tape will be the final finish. The shellac brings out the color of the grain and gives the wood a nice redish tint, while the Deft spray gives it a softer, lightlly textured look.

Hopefully I'll be able to start finishing the enclosures this weekend.

[Tim Prater]

I just thought I’d add a cautionary note about shellac. It’s important to use fresh shellac because it has a shelf life and will go bad over time (before it’s applied, that is). This occurs mostly after it’s mixed (i.e. liquid), but can also happen to the dry flakes on occasion. Shellac that has gone bad will appear fine, but the finish will not fully harden when it dries – it remains soft or gummy.

One way to test shellac for freshness is to place a big drop of liquid shellac on a piece of glass or other hard smooth horizontal surface, then let it dry overnight. The next day, try to poke your fingernail into the shellac drop. If it’s good, it will be hard and impervious to your fingernail. But if it’s bad, you’ll be able to dent the drop and it may feel gummy or soft.

I’ve used the Deft spray can lacquer may times on smaller projects when I didn’t want to break out the air gun. I live in Kansas, though, so I can get the “real” stuff, whereas in California you are probably limited to the waterborne variety that is safe to eat (just teasing – I used to live in CA too).:) I’ve never used the waterborne stuff, but I’ve been pretty happy with the performance of the solvent based type that I can get here. Most cans have a nice, flat, even fan-shaped spray pattern, but you’ll occasionally get one with a somewhat uneven pattern so be aware.

Your speakers look really nice – I’m envious.

Tim

[davepellegrene]

Ok, finally some progress with a few minutes here and there in between work overload and taxes.

I think I have the recipe down and am happy with the color and texture of the finish. Two coats of shellac that's mixed 50/50 with alcohol followed by sanding with steel wool following the first coat. Then two coats of the spray finish, again followed by sanding with steel wool following the first coat. The Deft finish is actually a waterborne acrylic (says so right on the can), so I am not sure why the sales person said it was a lacquer?

The test piece marked with the blue tape will be the final finish. The shellac brings out the color of the grain and gives the wood a nice redish tint, while the Deft spray gives it a softer, lightlly textured look.

Hopefully I'll be able to start finishing the enclosures this weekend.

Nice job! I like all three samples, but I guess the blue tapped one is what you were after. Its been a long time since I used shellac. I may have to give it a try again. Wonder if it would be better to use then sanding sealer under varnish?
Dave

[Ludo]

I just thought I’d add a cautionary note about shellac. It’s important to use fresh shellac because it has a shelf life and will go bad over time (before it’s applied, that is). This occurs mostly after it’s mixed (i.e. liquid), but can also happen to the dry flakes on occasion. Shellac that has gone bad will appear fine, but the finish will not fully harden when it dries – it remains soft or gummy.

One way to test shellac for freshness is to place a big drop of liquid shellac on a piece of glass or other hard smooth horizontal surface, then let it dry overnight. The next day, try to poke your fingernail into the shellac drop. If it’s good, it will be hard and impervious to your fingernail. But if it’s bad, you’ll be able to dent the drop and it may feel gummy or soft.Tim

That's a good tip. I'll have to remember and try that.


I’ve used the Deft spray can lacquer may times on smaller projects when I didn’t want to break out the air gun. I live in Kansas, though, so I can get the “real” stuff, whereas in California you are probably limited to the waterborne variety that is safe to eat (just teasing – I used to live in CA too).:) I’ve never used the waterborne stuff, but I’ve been pretty happy with the performance of the solvent based type that I can get here. Most cans have a nice, flat, even fan-shaped spray pattern, but you’ll occasionally get one with a somewhat uneven pattern so be aware.

Your speakers look really nice – I’m envious.

Tim

I don't have a spray gun "yet" so I'm stuck with using cans. Right now I'm more into amassing lots of speakers and making do with whatever tools I have; I should take a pic of my table saw so you guys could have a few chuckles.

Where in CA did you live?

Louis

[Ludo]

Nice job! I like all three samples, but I guess the blue tapped one is what you were after. Its been a long time since I used shellac. I may have to give it a try again. Wonder if it would be better to use then sanding sealer under varnish?
Dave

Dave,

They look a lot better in the picture than close up except for the test sample on the right.

Top left - three coats of acrylic spray only. Looks nice, but too flat and I'm concerned about long term adhesion.

Bottom left - three coats of full strength shellac. Looks ok from far away, but terrible up close with heavy streaks and raised areas that would not sand out. I didn't try the alcohol laden tampon method to get these out.

Bottom middle - same as above but with three coats of spray on top of the shellac. Looks ok, but some smooth, untextured streaks up close.

Top right - two coats of diluted shellac. Looks very nice but shiny surface won't hide the imperfections in my veneer application. My first enclosure has quite a few of them while the second is almost perfect.

Bottom right - same as above but with two coats of spray. Very uniform finish, not too reflective, fine grain texture will help hide veneer imperfections.

Louis

[davepellegrene]

Dave,

They look a lot better in the picture than close up except for the test sample on the right.

Top left - three coats of acrylic spray only. Looks nice, but too flat and I'm concerned about long term adhesion.

Bottom left - three coats of full strength shellac. Looks ok from far away, but terrible up close with heavy streaks and raised areas that would not sand out. I didn't try the alcohol laden tampon method to get these out.

Bottom middle - same as above but with three coats of spray on top of the shellac. Looks ok, but some smooth, untextured streaks up close.

Top right - two coats of diluted shellac. Looks very nice but shiny surface won't hide the imperfections in my veneer application. My first enclosure has quite a few of them while the second is almost perfect.

Bottom right - same as above but with two coats of spray. Very uniform finish, not too reflective, fine grain texture will help hide veneer imperfections.

Louis


I noticed you said "sanded with steel wool".
I always sand with paper first,very lightly usually with a soft backer pad with around 400 grit, to flatten the finish and then follow with steel wool to even out the sheen. The sand paper only hits the high spots and leaves the low spots shinny. If you follow with the steel wool it will even out the shine.
You can always use polish to get them shinier if you want.

Dave

[Ludo]

I noticed you said "sanded with steel wool".
I always sand with paper first,very lightly usually with a soft backer pad with around 400 grit, to flatten the finish and then follow with steel wool to even out the sheen. The sand paper only hits the high spots and leaves the low spots shinny. If you follow with the steel wool it will even out the shine.
You can always use polish to get them shinier if you want.

Dave

Hi Dave,

Just to clarify, for the samples on the left I used 300 grit sand paper.

For the sample on the right, I first sanded the wood with 300 grit sand paper and cleaned it with alcohol. Then I applied one coat of shellac and sanded it with very fine steel wool just to remove the surface roughness. Then another coat of shellac with no sanding. Then one coat of acrylic followed by sanding with steel wool, although it really didn't look like it needed it. Then the final coat of acrylic.

I want to avoid a shiny surface because the veneer has a few ripples where the epoxy bulged out a bit due to non-uniform surface pressure, especially on the back of one of the enclosures. I'm sure I could do a better job of this next time, but it'll have to do for this build.

Louis

Louis

[Ludo]

Thanks to everyone's advice and help, I was able to complete the enclosure finish last week in time for the Norcal DIY meet. The pedestals still need the finish applied, and I do plan to make a cloth grill, but there's no rush on these since my sister's B-day isn't until July.

So now I get to listen to these for a few months and work on some new projects for a while :)

Louis

[charlielaub]

I'd just like to say that these were judged to be one of the best sounding and tonally well balanced speakers at the DIY event last weekend. There was even some wonderful bass extension from the diminutive AC130's. Great job on these!

-Charlie

[davepellegrene]

Wow! those really look nice. Sounds like they sound just as good as they look.
Now you get to give them to, I believe it was, your sister.
Dave

[Wolf]

Heh- Baby got Back! :D

They look good, Louis!
Wolf

[Ludo]

Thanks very much guys.

Charlie,

Appreciate your kind words about the sound.
I guess that 3 months of tuning paid off.

Louis

[Ludo]

Finally delivered and installed the speakers at my sister's place last night; she turned 30 on Wed. and she was real excited to see what she got when I pulled the pillow cases off them. She said she was feeling left out because I hadn't built her a set of speakers yet.

She currently lives in a 15' x 15' studio apartment plus kitchen, bath and walk-in closet so even with the 40Wpc NAD amp http://www.audioadvisor.com/prodinfo.asp?number=NAC316BEE these can shake up the place pretty well. Her existing DVD player didn't have an extra audio output so we had to tap into the audio output of the TV which limited the sound quality pretty severely, but it still sounded way better than her TV speakers.

I think my wife and son are going to miss these, but its good to give them a new and appreciative home; I'll miss them too. :o

Louis

[bobbarkto]

Very nice work! Classy.
They look right at home, too.

[Ludo]

Very nice work! Classy.
They look right at home, too.

Thanks Bob,

I should have clarified; that photo was taken at my place, but I'll try to get a pic of the final install next time I visit her.

Louis

[bobbarkto]

Too bad, for you! :D
I can see why the family would miss them.


Thanks Bob,

I should have clarified; that photo was taken at my place, but I'll try to get a pic of the final install next time I visit her.

Louis