Is there interest in a large three way "monkey coffin" collaboration?

[Mayhem13]

Re: Is there interest in a large three way "monkey coffin" collaboration?

2. Having two mids may help smooth the diffraction ripples.

http://www.madisoundspeakerstore.com...1/2-wool-cone/

I've heard this a few times lately and seem some posted sims but man, I'd really like to see a real world measure of it as it seems so counter intuitive with one cones wave rolling over another. If the smoothing really does occur, that opens quite a few possibilities IF one mounts the drivers horizontally which won't create any addition vertical lines BUT might reduce horizontal directivity just enough. Interesting.

[Mayhem13]

Re: Is there interest in a large three way "monkey coffin" collaboration?

That is true. In spite of my earlier mention of the DC380 the ST305 certainly makes the most sense.

So what do we do to make this worth doing as opposed to the "Rockin It Old School". Clearly that isn't a project that gets a lot of mentions or recommendations on the board.

Is just using a smaller mid and a different crossover enough to make this project worth doing as a new contribution to the DIY speaker community?

Would a different tweeter plus a different mid make it worthwhile? SB26STCN?

Would using a more "hifi" marketed mid make it enough different? Scan Disco? A pair of the Silver Flutes? Or just focus on the same basic design ( smaller mid and different crossover) but perhaps executed a little differently in some areas enough different?

At this point where the midrange is concerned, you'll probobly have to stop here and smell the roses.....or in other words 'listen' to some mid drivers for yourself. With your proposed crossover points, the mid driver will be producing nearly ALL of the vocal range and within the most critical range of hearing. It will be the primary 'voice' of this design. Whether we like it or not, measurements or sims aren't going to reveal the tonal quality of a driver at all. We could make subjective speculation as to the cone material,CSD and HD but it won't really explain why a Scanspeak 15M sounds the way it does......or my much favored and less expensive 6MD38.

If you want to voice the speaker for a classic 3way, you're going to have to listen to a few mids. Take a look over at Curt's pages and you'll see just how much emphasis they place on midrange voicing.

Whichever woofer you choose ( they're both great choices at the price point) both will essentially limit your midrange choices. I can't really see sacrificing efficiency here....padding a woofer and tweeter in a big box speaker just doesn't add up.

This is your baby but I gotta ask again.........third time I've seen a mention of the 'sealed' response of a woofer in X volume?.....is there a preference for a sealed nearfield monitor speaker? If so, I apologize as I've been waaaaaay off base in my input since the get go.

[andy19191]

Re: Is there interest in a large three way "monkey coffin" collaboration?

That is true. In spite of my earlier mention of the DC380 the ST305 certainly makes the most sense.

I was referring to the ST385-8 (not the DC380) which I think is an option to be considered in a ported 130 litre cabinet. If you are going for a big floor stander rather than a 75 litre monitor then I would expect it to do bass. I don't see sensitivity as a particularly important parameter for such a floor stander and dropping the sensitivity a dB or two makes the midrange choice easier. However it would push the budget from $400 to perhaps $500 dollars.

So what do we do to make this worth doing as opposed to the "Rockin It Old School". Clearly that isn't a project that gets a lot of mentions or recommendations on the board.

The budget big monitor I am working on is close to the "Rockin It Old School" design in size, price and configuration because they are examples of the same type of speaker at the same price point. Initially you seemed to want a speaker that had more bass, was a bigger floor standing tower and had hi-fi speaker sensitivity. If this is still what you want to do then specify it as the objective and perhaps revise the price. I doubt you will end up with something close to the "Rockin It Old School" design.

Is just using a smaller mid and a different crossover enough to make this project worth doing as a new contribution to the DIY speaker community?

That is pretty much what I am proposing to do. I have found the "Rockin It Old School" design useful in confirming I do not want to use a 4 ohm tweeter and only want to use a 8" midrange as a last resort. The write up lacks some basic details like the crossover and cabinet design which means someone new to speaker DIY is very unlikely to consider building it.

Would a different tweeter plus a different mid make it worthwhile? SB26STCN?

Would using a more "hifi" marketed mid make it enough different? Scan Disco? A pair of the Silver Flutes? Or just focus on the same basic design ( smaller mid and different crossover) but perhaps executed a little differently in some areas enough different?

If you have two roughly equal alternatives that meet the objectives for the design then going for the one that was not used in a similar design makes some sense. However I think the objectives for the design are currently a bit too vague to make decisions like this.

Being "hi-fi" or "pro" needs defining as an objective. If you opt for the former then it influences the choice of woofer and midrange and leads to a drop in sensitivity in order to achieve it at budget price level. I think doing it this way round rather than picking a driver and looking at the consequences is likely to make the decision making easier.

The pros and cons of two small mids versus one big mid for the design could be worked through before looking at concrete examples. Two mids were not an option for the monitor I wanted but they are for a bigger floor standing tower.

What is the design?
- a 42" tall floor standing tower has been settled by the poll
- $400 budget - subject to revision upto $500?
- bass extension not defined - an important design parameter
- 100 litres volume - subject to revision upwards to 125-150 litres?
- sealed or ported not defined - leaning towards ported
- hi-fi or pro not defined - leaning towards hi-fi
- 1 or 2 mids not defined - leaning towards 1 x 6.5"
- sensitivity not defined - follows from hifi/pro, bass extension,...
- ...

[andy19191]

Re: Is there interest in a large three way "monkey coffin" collaboration?

We could make subjective speculation as to the cone material,CSD and HD but it won't really explain why a Scanspeak 15M sounds the way it does......or my much favored and less expensive 6MD38.

The B&C midrange would do very nicely but it is too expensive to consider. The Scan-Speak midrange is significantly cheaper. If the objectives of the design were to be changed towards more sound quality and the budget raised then spending $180 of it on the midrange drivers might make sense. However, a strong move towards "hi-fi" is almost certain to mean the sensitivity of the B&C mids would be unnecessary.

[lorenmjones]

Re: Is there interest in a large three way "monkey coffin" collaboration?

Listening to several midranges would probably be wise and perhaps I'll order a couple different ones.

The 6MD38 looks like a great midrange and may need a little higher crossover which would put more BSC in the range of the mid. That may keep the sensitivity a little higher and this driver has the requisite sensitivity. It actually costs $22 more than the Scan Speak however. I am a huge B&C fan by the way.

I keep mentioning sealed performance when referencing the 15" woofers because I think some people may prefer the way a sealed design integrates with their room. I don't prefer sealed and whatever I build as a prototype (and to keep myself or gift) will be a ported version. I think a sealed version could be workable with a 15" woofer, but the ST305 doesn't do as well sealed and would be vented only in my mind.

At this point where the midrange is concerned, you'll probobly have to stop here and smell the roses.....or in other words 'listen' to some mid drivers for yourself. With your proposed crossover points, the mid driver will be producing nearly ALL of the vocal range and within the most critical range of hearing. It will be the primary 'voice' of this design. Whether we like it or not, measurements or sims aren't going to reveal the tonal quality of a driver at all. We could make subjective speculation as to the cone material,CSD and HD but it won't really explain why a Scanspeak 15M sounds the way it does......or my much favored and less expensive 6MD38.

If you want to voice the speaker for a classic 3way, you're going to have to listen to a few mids. Take a look over at Curt's pages and you'll see just how much emphasis they place on midrange voicing.

Whichever woofer you choose ( they're both great choices at the price point) both will essentially limit your midrange choices. I can't really see sacrificing efficiency here....padding a woofer and tweeter in a big box speaker just doesn't add up.

This is your baby but I gotta ask again.........third time I've seen a mention of the 'sealed' response of a woofer in X volume?.....is there a preference for a sealed nearfield monitor speaker? If so, I apologize as I've been waaaaaay off base in my input since the get go.

[lorenmjones]

Re: Is there interest in a large three way "monkey coffin" collaboration?

A very helpful post here Andy, thanks.

-yes 42" floor standing tower has been confirmed
-yes I think revising budget up to $500 is worth considering if it adds to performance (Rockin it old school is about $450)
-Bass extension in my book needs to be F3 of 30 hz or below
-100 liters has been my target all along but if the baffle is 42x15 then 12.5" deep will give you 100 liters plus change for driver displacement etc. 16.5" deep will get you in that 130 liter ballpark. Not really a big difference there in my book so it would be worth considering if performance improved substantially
-Ported (with a sealed option at builder's preference if using one of the 15" woofers discussed so far)
-I'm leaning more toward hifi than pro in the objectives, so perhaps that should assist in the driver choice regarding the midrange. Really I have a compromise in mind. Better LF extension than some monitor type designs but lower sensitivity as a tradeoff. As far as the voicing character I would favor accuracy. I have a speaker in my living room with all pro drivers and it sounds awesome. I kind of want to explore how much different a more rigid cone midrange sounds than the paper ones I have now however...but many may prefer a paper cone in this design.
-I'd like to see final sensitivity break 90db for 1 watt with impedance in the 6ohm range (don't mind if it drops a little more in the top octaves)

So in answering those questions I think the woofer is still the ST305. It gives a compromise of extension and efficiency. The ST385 costs $30 more and does offer a little more output in the area below 30hz with an F3 of 25 in 130 liters vs 29 in 100 liters for the ST305. I think that the extra 5 hz isn't worth the $30 and the 30 liters extra volume required.

As far as a mid I do think the B&C is very nice but unnecessarily expensive as we don't need all that sensitivity. The Faital 6Fe100 is slightly low on sensitivity but may be adequate and the 6Fe200 is plenty sensitive but has a slightly ragged response. The ScanSpeak costs a little more but has what looks to be plenty of sensitivity and has a smoother response. There is not a lot of community knowledge (people here using them and posting real world measurements etc) of any of these drivers although there is a pretty good set of measurements on the Scan's little brother the 10F and it performed quite nicely.

http://medleysmusings.com/scan-speak...4-ohm-version/

I was referring to the ST385-8 (not the DC380) which I think is an option to be considered in a ported 130 litre cabinet. If you are going for a big floor stander rather than a 75 litre monitor then I would expect it to do bass. I don't see sensitivity as a particularly important parameter for such a floor stander and dropping the sensitivity a dB or two makes the midrange choice easier. However it would push the budget from $400 to perhaps $500 dollars.


The budget big monitor I am working on is close to the "Rockin It Old School" design in size, price and configuration because they are examples of the same type of speaker at the same price point. Initially you seemed to want a speaker that had more bass, was a bigger floor standing tower and had hi-fi speaker sensitivity. If this is still what you want to do then specify it as the objective and perhaps revise the price. I doubt you will end up with something close to the "Rockin It Old School" design.


That is pretty much what I am proposing to do. I have found the "Rockin It Old School" design useful in confirming I do not want to use a 4 ohm tweeter and only want to use a 8" midrange as a last resort. The write up lacks some basic details like the crossover and cabinet design which means someone new to speaker DIY is very unlikely to consider building it.


If you have two roughly equal alternatives that meet the objectives for the design then going for the one that was not used in a similar design makes some sense. However I think the objectives for the design are currently a bit too vague to make decisions like this.

Being "hi-fi" or "pro" needs defining as an objective. If you opt for the former then it influences the choice of woofer and midrange and leads to a drop in sensitivity in order to achieve it at budget price level. I think doing it this way round rather than picking a driver and looking at the consequences is likely to make the decision making easier.

The pros and cons of two small mids versus one big mid for the design could be worked through before looking at concrete examples. Two mids were not an option for the monitor I wanted but they are for a bigger floor standing tower.

What is the design?
- a 42" tall floor standing tower has been settled by the poll
- $400 budget - subject to revision upto $500?
- bass extension not defined - an important design parameter
- 100 litres volume - subject to revision upwards to 125-150 litres?
- sealed or ported not defined - leaning towards ported
- hi-fi or pro not defined - leaning towards hi-fi
- 1 or 2 mids not defined - leaning towards 1 x 6.5"
- sensitivity not defined - follows from hifi/pro, bass extension,...
- ...

[Mayhem13]

Re: Is there interest in a large three way "monkey coffin" collaboration?

I'd be surprised after auditioning mids if you didn't clearly prefer paper/poly over all others but that's just my opinion.

You're right, efficiency isn't everything and I'm glad you've proclaimed a priority level for it so it's time to move in the hifi direction.

That being said, a show of support for PE on their forum would be great......and considering the new RS150P for midrange duties equally forward thinking. The breakup mode is so high and benign that I doubt it would even need a notch. Cost is certainly in line. Off axis behavior at 2.5-3hz is excellent. Not much not to like here. On a 14" wide baffle in its own sealed chamber, it may only need 1-2db of compensation.

[lorenmjones]

Re: Is there interest in a large three way "monkey coffin" collaboration?

DP

[isaeagle4031]

Re: Is there interest in a large three way "monkey coffin" collaboration?

Just an FYI. I'm still following the thread though I haven't posted lately. I am in the design stage of a similar project as I have the drivers on hand. ST305, silver flute 6.5(8ohm) and maybe the tb 28-537sh tweet. 2.6ish cubes tuned to 35hz.

[lorenmjones]

Re: Is there interest in a large three way "monkey coffin" collaboration?

Well I certainly do enjoy the character of my 18Sound 6ND430's so you may be right on paper cones. I didn't love the Seas P17 poly midbass I had years ago as much as I enjoy the paper mid speakers I've used. I've never owned any metal cones. I do have a pair of Nomex Peerless MTM's upstairs and they sound good. Frankly I am not a hypercritical listener and I have come to the conclusion that the on axis FR is most important to me followed by polars and the ability of the system to reach the desired output level without having the distortion start to rise as it reaches it's limits.

The RS150P has admirably smooth response and measurements have shown good distortion performance. It is rated 89db but looking at their FR plot that looks slightly optimistic. Do you think the RS150P will have adequate sensitivity to match the woofer...clearly it is a very good driver at a very good price.

I'd be surprised after auditioning mids if you didn't clearly prefer paper/poly over all others but that's just my opinion.

You're right, efficiency isn't everything and I'm glad you've proclaimed a priority level for it so it's time to move in the hifi direction.

That being said, a show of support for PE on their forum would be great......and considering the new RS150P for midrange duties equally forward thinking. The breakup mode is so high and benign that I doubt it would even need a notch. Cost is certainly in line. Off axis behavior at 2.5-3hz is excellent. Not much not to like here. On a 14" wide baffle in its own sealed chamber, it may only need 1-2db of compensation.

[lorenmjones]

Re: Is there interest in a large three way "monkey coffin" collaboration?

That sounds like a pretty cool design. Those Silver Flutes do look to have a very smooth response. Do you have an idea yet what your final sensitivity will be (assuming you are limited by the ST305). Obviously baffle width and woofer proximity to the floor as well as crossover point will all affect this. I assume though that you find the Silver Flute to have adequate sensitivity to keep up with the ST305...glad you are still following along.

Just an FYI. I'm still following the thread though I haven't posted lately. I am in the design stage of a similar project as I have the drivers on hand. ST305, silver flute 6.5(8ohm) and maybe the tb 28-537sh tweet. 2.6ish cubes tuned to 35hz.

[wg_ski]

Re: Is there interest in a large three way "monkey coffin" collaboration?

You could probably live with a mid that was 3dB less sensitive than the woofer, if it can handle the power gracefully. In the crossover design, you can get a sensitivity boost in a band pass network at the expense of it dipping in impedance. Watch it with 4 ohm (or multiple) drivers. A lot of revievers don't like loads dipping to 2.8 ohms in the low midrange and sound like nails on chalkboard when the limiting kicks in on a vocal fundamental.

I'm curious about the Scan Disco mid - how it compares power compression wise to the pro mids being considered. I know from experience that these pro mids will continue to sound nice when driven hard - where a 15 watt Tangband goes to hell when trying to peak at 110 dB.

[isaeagle4031]

Re: Is there interest in a large three way "monkey coffin" collaboration?

My guestimate would be around 87 or so. The silverflutes have some issues around 2k so I will be crossing them around there. Personally I prefer a 4ohm woofer, about a 6-8 ohm mid, and 8ohm tweet for cost purposes. Mids will go in about a .3 cube sealed sub enclosure. Overall height about 39".

[lorenmjones]

Re: Is there interest in a large three way "monkey coffin" collaboration?

OK. Good info on the sensitivity side. So mids at 88 to 89 db should be OK to consider.

I was alluding to exactly the power compression concerns you mention in my statement above about wanting a system that reaches the desired output without having distortion start to rise. Power compression in that setting is just another form of distortion as levels start to rise. I totally agree about the TB. There is a nice looking 6" TB that is sensitive enough but only handles 15watts...that won't get it done for this design. I would like the entire system to do 110 db (on paper based on sensitivity and continuous power handling specs) realizing that power compression will start to creep in several db below that level.

Scan rates the 15m for 75 watts per the IEC 17.1 100hr noise test using a 200 hz 2nd order highpass

You could probably live with a mid that was 3dB less sensitive than the woofer, if it can handle the power gracefully. In the crossover design, you can get a sensitivity boost in a band pass network at the expense of it dipping in impedance. Watch it with 4 ohm (or multiple) drivers. A lot of revievers don't like loads dipping to 2.8 ohms in the low midrange and sound like nails on chalkboard when the limiting kicks in on a vocal fundamental.

I'm curious about the Scan Disco mid - how it compares power compression wise to the pro mids being considered. I know from experience that these pro mids will continue to sound nice when driven hard - where a 15 watt Tangband goes to hell when trying to peak at 110 dB.

[isaeagle4031]

Re: Is there interest in a large three way "monkey coffin" collaboration?

Don't discount a mid or tweeter with a lower power rating. Most of the power is consumed by the woofer. I am using a MarkAudio Alpair10 and even when I biamp (adcom gfa555 200w/ch) there are no issues with capacity.