My first 3 way speaker build

[rpb]

Re: My first 3 way speaker build

I've only had about maybe an hour of listening time so far and I want to play with it. That's where I'll start, I have dacron and some polyfill and I'll play with that first. I didn't stuff them because I wanted to listen first to the difference lining the cabinet made.

To be completely honest (and not to start a huge war), I don't think stuffing makes a super huge difference either way. But I'll play with it and find out.

I wouldn't expect you to hear a difference after adding dacron or polyfill, but I would expect you to hear a big difference with a few slabs of egg crate foam in the box. I guess that's damping, and not actually considered stuffing.

[mattsk8]

Re: My first 3 way speaker build

I wouldn't expect you to hear a difference after adding dacron or polyfill, but I would expect you to hear a big difference with a few slabs of egg crate foam in the box. I guess that's damping, and not actually considered stuffing.

In a cabinet with a woofer crossed at roughly 225 hz, where would I hear the egg crate difference? I already have one of the cabinets internally lined with 1" thick acoustic foam. I'll use egg crate foam behind a midwoofer in a TM if I'm getting excessive cabinet noise, but I don't see the benefit here.

[isaeagle4031]

Re: My first 3 way speaker build

In a cabinet with a woofer crossed at roughly 225 hz, where would I hear the egg crate difference? I already have one of the cabinets internally lined with 1" thick acoustic foam. I'll use egg crate foam behind a midwoofer in a TM if I'm getting excessive cabinet noise, but I don't see the benefit here.

It really won't make any difference in the woofer cabinets, especially when crossed that low. My Intrepids are crossed at 300, 3 cubes slot port, tuned to 25hz. No issues there and plenty of people have heard them.

[Mike220]

Re: My first 3 way speaker build

Very interesting build here. I thinkk you should drag it to chicago but thats just me!

[hongrn]

Re: My first 3 way speaker build

Looking good Matt! Looking forward to see this project completed soon.

Hong

[[email protected]]

Re: My first 3 way speaker build

Measure the woofer at the same distance and drive level on axis as you do for the T/M (something like 24" is plenty of distance). Set the gate like you normally would to filter out all of the low end room related junk and save that curve. Now measure the woofer nearfield and adjust the level so the curve overlaps at the frequency your gate from the previous measurement starts. Save both curves. Use print screen and MS paint to remove the garbage and run the combined curve through SPL Copy. If there's a low frequency noise floor in your measurements like many people have you can also run the results through response modeler to add a filter that removes the junk.

You will need to do this for your mid as well. That noise floor in the mid/tweet measurements will throw off the phase in your x over sim.

or this.......http://audio.claub.net/software/FRD_...r/Blender.html

[Ray Tremblay]

Re: My first 3 way speaker build

[ATTACH=CONFIG]59162[/ATTACH]

Nice. I love a small 3 way with a 10 on the bottom. A Scan mid is always a bonus, too.

[fatmarley]

Re: My first 3 way speaker build

Stuffing -

Dacron does next to nothing. Egg crate foam will work if it's open cell stuff and the best place to put it is in the mid/tweet box. Other materials you can try are Acoustastuf and Monacor MDM3 - the best is arguably fiberglass but I'd only use fiberglass in a sealed box for obvious reasons.

The reason for stuffing is to attenuate midrange reflections to try to stop them coming back through the cone. If you go too mad with stuffing, you can make the midrange sound dull, so it's well worth experimenting.

As others have said - great choice of drivers and if you get the crossovers and stuffing right they should sound great.

[marvin]

Re: My first 3 way speaker build

Very interesting build here. I thinkk you should drag it to chicago but thats just me!

+1

[mattsk8]

Re: My first 3 way speaker build

Stuffing -

Dacron does next to nothing. Egg crate foam will work if it's open cell stuff and the best place to put it is in the mid/tweet box. Other materials you can try are Acoustastuf and Monacor MDM3 - the best is arguably fiberglass but I'd only use fiberglass in a sealed box for obvious reasons.

The reason for stuffing is to attenuate midrange reflections to try to stop them coming back through the cone. If you go too mad with stuffing, you can make the midrange sound dull, so it's well worth experimenting.

As others have said - great choice of drivers and if you get the crossovers and stuffing right they should sound great.

Great post and I agree with all of it, mainly just wanted to stir the pot a bit ;). Stuffing works if it's needed, but only when and where it's needed.

Thanks for the compliments everyone!! Tonight I'll finally get some lengthy play time with them. My main focus for now is going to be on the bass section. I need to loosen these up before jumping the gun on anything, it's a 10" paper cone woofer with a fairly beefy surround and motor. I'm hoping after playing some Lorde, DJ Magic Mike and maybe some NIN through them they'll start to come to life. Otherwise I'll be building a different bass cabinet.

[dlneubec]

Re: My first 3 way speaker build

I got the cabinets roughed in about a month ago, and I now have a crossover roughed in!!! Now I need to voice these and play with the bass cabinets a bit. I kind of feel a bit... out of my league :o. IMO voicing these is like having to drive the space shuttle down the expressway during rush hour, because there is so much going on (they're revealing to say the least). All the drivers are incredible, the SS 18w mid is nothing short of spectacular, and the SS HDS tweeter is a perfect fit for it; the mids and highs aren't lacking anywhere.

This all measures pretty flat right now, but the bass is a tad wonky, I need to play with stuffing. There's a bit of a dip in the 100Hz region, but that could've been the room too. I have the woofer crossed at about 250-225, and mid is at about 2.3k. I have one of the cabinets lined with 1" thick, spongy adhesive backed foam, the other is empty. I'll play with swapping woofer position (on the floor verses how it is in the pic), then I'll play with different stuffing. FWIW, I called Madisound and they said their cabinet dims were good to go, so I used their specs for the SB29 woofer and built the woofer cabinet 2.0 cf, with a 3" x 12" precision port, which should have a F3 of around 27 Hz. Once I get the bass where I like it, I'll move on with my attempt to voice those mids and highs :eek:.

No real questions (yet), just thought I'd update progress. So far what I think I love is how revealing these are, but I've only had about an hour of play time with them.

[ATTACH=CONFIG]59161[/ATTACH] [ATTACH=CONFIG]59162[/ATTACH]

Matt,
If you flip your bass bin over so that the woofer is nearest the floor, you may have a flatter response in the 100-200hz range (Allison boundary effect). Also, there may be a bit more boundary reinforcement on the woofer output, which might allow you to apply less attenuation on the mid and tweet and increase overall sensitivity. You may have to decrease the amount of baffle step you are applying in the crossover a bit, or not, depending upon how it sounds in your room and in the position you expect to place them in.

You might just audition them as they are then flip the bass bin over and compare the results.

[mattsk8]

Re: My first 3 way speaker build

Matt,
If you flip your bass bin over so that the woofer is nearest the floor, you may have a flatter response in the 100-200hz range (Allison boundary effect). Also, there may be a bit more boundary reinforcement on the woofer output, which might allow you to apply less attenuation on the mid and tweet and increase overall sensitivity. You may have to decrease the amount of baffle step you are applying in the crossover a bit, or not, depending upon how it sounds in your room and in the position you expect to place them in.

You might just audition them as they are then flip the bass bin over and compare the results.

Thank you Dan!! Flipping the cabinet was actually the first thing I did, but I didn't have much time to play after I did that. For the brief moments I listened it seemed to actually make a pretty big difference. I'll definitely play more tonight. Where I was a bit disappointed was listening to Pink Floyd, The Thin Ice. Listening to that track from the beginning, all is amazing right up till about 1:42 when the bass kicks in. The woofers tend to thud more than thump or pound like I expected them to. Hopefully it's because they're new, but if I can't make that better I'll build different cabinets or even use different woofers.

Edit: FWIW, I shouldn't have said anything because I've definitely had enough experience with subs and woofers to know that (generally) they always sound like that when they're new. I remember being thoroughly disappointed with my JL Audio 12w3 subs when I first powered them up in my car years back, but after a few days of hammering on them, all of a sudden I got in and they were magical. So I'll give them some time before I do anything rash .

[mattsk8]

Re: My first 3 way speaker build

Long update...

This has a been a learning experience, as well as a bit of an expensive, uphill battle. These SB29 woofers are no good (IMO) in a passive 3 way, I honestly think I'm out the $340 for the pair of these if I want to stay with a passive 3 way. And here's why...

The bass in my Blues mops the floor with these. That's pretty harsh, but true. I'd say the f3 in these is somewhere around 50Hz, but even worse than that is the bass is inconsistent; they plain old sound bad on the bottom end.

I have a B&K preamp with a subwoofer out, and also a spare Carver amp. If I run these SB woofers active using my sub out and that Carver amp to power them, and cross them at 200 Hz (as high as my preamp allows), they sound magical; the bass is perfect. You might think that means you should be able to get that same sound by padding the mids and highs with resistors and getting the passive crossover on the woofer right, but unfortunately I can't seem to make these SB woofers work on a passive crossover.

I saw a design Madisound did that had 2 of these SB woofers in it, and I was hoping it was 1 woofer with 1 passive radiator, but I called them and it was actually 2 of these 10" SB29 woofers. The issue with that is, if I went that route, the impedance drops down to about 1.25 ohms :eek:, and I don't have an amp that'll manage that.

So I really have 2 options that I'm aware of (unless someone here can tell me how to make these woofers work)... either I redo the crossover from my Scanspeak mid to tweeter, then run these woofers active... or I scrap using these woofers altogether and find different woofers. Scrapping the SB woofers and going with something else will be expensive, I think I'll be in Scanspeak Revelator 10" territory if I have to go that route before I'll find a woofer that'll play nice with a passive crossover (unless someone here has an idea for one).

What do you guys think?? Am I missing something?

[Wolf]

Re: My first 3 way speaker build

Something tells me you're missing something.
They ought to be good woofers,
Wolf

[mattsk8]

Re: My first 3 way speaker build

Something tells me you're missing something.
They ought to be good woofers,
Wolf

I hope you're right, but I'm getting mixed reviews. I have a 15 gauge, 3.0 inductor with a 250 mfd shunt cap on the woofer. I've been told to try to tame the tall impedance peak at about 38Hz with an "impedance trap" (impedance spikes to 22 ohms at 38Hz, then drops like a rock to below 4 ohms at about 50 Hz), but I've also been told that won't do anything, that bump is normal.

This is the woofer I'm using. SB Acoustics SB29NRX75-6 10" woofer

I've been told by many that the stats on Madisound's site for that woofer are very usable. Anyone here know more about this than I do? Would someone be willing to give an idea of a crossover for this woofer? Looking to cross at about 225 to 250, with a 12 or 18 db slope. I don't necessarily care so much at this point if it's perfect for this design, I really just want to know if it's possible to make this play bass with a passive crossover. I guess based on that, the frequency and slope doesn't even matter. I just want to know, ya know If I could just make this play bass with a passive crossover, I can make the top work with it as long as it doesn't go much higher than 300 (I'll get some heavy mid out of the woofer if I go much past 300).

The hardest part for me to stomach at this point is how magical this sounds when I use it active. And I've been told to just stay active since it obviously works. But dog-gone it, that wasn't the plan!!! I really want to do this passive. You guys must understand that right?!