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

[lowpolyjoe]

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

I'm enjoying following this thread. Can't wait to see what you guys come up with.

I'm curious if anyone here has built Zaph's SB design mentioned in the opening post (I assume you're referring to the MTMW sealed setup). I was *very* close to ordering that kit a few times but chickened out. It is a bit expensive

[lorenmjones]

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

SB 12.3 looks like it should be a truly great sounding speaker. At that price it would compete with the Statements and some others. $1000 in DIY land should get you a pretty great sounding pair of speakers without doubt.

Hopefully we can do something for less than half that price that will get loud enough to party a little but still sound good enough to not embarass itself in critical listening environments. That's my goal...

I'm enjoying following this thread. Can't wait to see what you guys come up with.

I'm curious if anyone here has built Zaph's SB design mentioned in the opening post (I assume you're referring to the MTMW sealed setup). I was *very* close to ordering that kit a few times but chickened out. It is a bit expensive

[lorenmjones]

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

OOOPS!!

I modeled with wrong TS parameters on my last post. These should be correct.

DCS380-4 100 liters fully stuffed. F3/F6/F10 is 36/29/22. Max output is 109.5 db above 100hz. It will handle 160 watts before exceeding xmax at 30 hz. Max output at 30 hz is 104db.

DC380-8 100 liters walls lined with batting. F3/F6/F10 is 42/32/24. Max output is 105.6 db above 100 hz. It will handle 35 watts before exceeding xmax at 30 hz. Max output at 30 hz is 98db.

The "max output above 100hz" number was derived using the power input that would hit excursion limits at 30 hz so might be a little conservative but it should be similarly conservative for both woofers.

Again I could see either of these woofers working. I would prefer the DCS380-4 if others agree given that it has about 4 db more output in the upper bass and 6 db more in the lower bass. If the 4 ohm impedance and the response shape in the upper bass/lower mids is not prohibitive then that would be my vote.

What does everyone think.

At this point I would pair it with the Faital FE200 (or that 6" Celestion) and the Vifa BC25SC06. Thoughts?

[andy19191]

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

DCS380-4 100 liters fully stuffed. F3/F6/F10 is 36/29/22. Max output is 109.5 db above 100hz. It will handle 160 watts before exceeding xmax at 30 hz. Max output at 30 hz is 104db.

DC380-8 100 liters walls lined with batting. F3/F6/F10 is 42/32/24. Max output is 105.6 db above 100 hz. It will handle 35 watts before exceeding xmax at 30 hz. Max output at 30 hz is 98db.

The "max output above 100hz" number was derived using the power input that would hit excursion limits at 30 hz so might be a little conservative but it should be similarly conservative for both woofers.

Again I could see either of these woofers working. I would prefer the DCS380-4 if others agree given that it has about 4 db more output in the upper bass and 6 db more in the lower bass. If the 4 ohm impedance and the response shape in the upper bass/lower mids is not prohibitive then that would be my vote.

What does everyone think.

For a sealed box you need to consider the Q as well as the extension.

At this price point we are always going to find drivers that are noticeably better that cost a little bit more. I am not familiar with these drivers but having had a very brief browse of 12" and 15" Dayton drivers costing under a $100 I would suggest adding a vented ST305-8 to the list. It is 8 ohms, sensitivity around 92 dB, max SPL around 115dB, volume around 75 litres, F3 around 35-40Hz depending on tuning. The bass extension is OK, it is vented rather than sealed but is a comfortable 8 ohms in a reasonable volume with the sensitivity and max SPL of something like a big monitor.

[lorenmjones]

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

I did consider Q of the sealed alignments. Both were in the .7 to .74 range.

I'll take a look at ST305-8. Thanks.

What advantages do you see it having over the sealed 15" choices? Box size? Max output? Smoother response in lower mids and upper base? Just trying to learn what things to look for?

For a sealed box you need to consider the Q as well as the extension.

At this price point we are always going to find drivers that are noticeably better that cost a little bit more. I am not familiar with these drivers but having had a very brief browse of 12" and 15" Dayton drivers costing under a $100 I would suggest adding a vented ST305-8 to the list. It is 8 ohms, sensitivity around 92 dB, max SPL around 115dB, volume around 75 litres, F3 around 35-40Hz depending on tuning. The bass extension is OK, it is vented rather than sealed but is a comfortable 8 ohms in a reasonable volume with the sensitivity and max SPL of something like a big monitor.

[cjd]

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

You can achieve similar results with a couple smaller drivers in a smaller box, and have a lot more flexibility in the crossover. Sure, it's a smaller monkey coffin

The DCS380-4 sure looks like it wants 180L or better sealed...

You can achieve similar results with a pro driver in a 100L box and have a lot more SPL capability.

When your F3 target was in the 20's, a lot made sense. These later iterations appear to be pulling back into the gee-whiz category.

The Dayton PA380-8 in 100L tuned to 28Hz looks pretty good to me (0.35ohm series impedance) too. You can cut that to 75L tuned to 30hz too. It wants a rumble filter for best results if you push it to its xmax. I'm not sure I'd go one route over another, but it's into territory I'm just not convinced you're getting your money's worth for the size.

If you've got room for box size, the RSS390HF wants like 300L sealed but hits 89.x at 2.35v for sensitivity and goes loooow. Or a huge box and port it even loooowwwwer.

Just food for thought - I'd also never bother building something with NPE caps any more, though I'll use Q-core inductors to manage series impedance. I'm not the one building this though

[andy19191]

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

I did consider Q of the sealed alignments. Both were in the .7 to .74 range.

I had the DCS380-4 needing a bigger volume than 100 litres. I have checked my numbers and they look OK but the Dayton site gives a sealed volume that agrees with yours so it is likely I am wrong even if I cannot see why.

What advantages do you see it having over the sealed 15" choices? Box size? Max output? Smoother response in lower mids and upper base? Just trying to learn what things to look for?

The higher sensitivity and higher max SPL are two things that I would look for in a big monitor. The smaller box size is nice but big monitors are big and 100 litres looks OK to me. I haven't looked at the smoothness of response. Sealed is nice but a port provides a lot of SPL where it is needed.

[andy19191]

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

When your F3 target was in the 20's, a lot made sense. These later iterations appear to be pulling back into the gee-whiz category.

There is clearly a choice that needs to be made. Inefficient with deep bass or efficient with sufficient bass. Whichever is chosen is going to disappoint some people.

[joeybutts]

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

I have the 8fe200's in my truck Loren if you are still in the area and want to audition/borrow.

[ngjockey]

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

There is one other option but I'm already regretting confusing the issue. Integrated, powered subs. Plate amps aren't too expensive but still getting over budget. Nice part about this is it takes a big load off the main amp and often allows more tuning flexibility. Think about how much you'll save on inductors and caps.

[Whitneyville1]

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

8 ohms 15" ported might be a compromise or a better 12" ported woofer that digs deeper and is more efficient but costs more is another thing to play with. I'm thinking Xmax should be at least as low as 30 Hz and 105+ dB and I can see it taking 50+ watts @ 8 ohms to get there. I know that takes more copper in the XO, and hurts the "price point", but the dynamic impedance of a "4 ohm" woofer at high SPLs will shut down many AVRs who's power supplies are a bit marginal. I'm not that smart. I've been reading some of Tympany's "white papers" on some of their woofers. (Google translate from Chinese now.) At 1 watt, a driver reads the "spec sheet" graph. At 30 watts, it usually doesn't.

Ngjockey's idea I thought of too. It's a tough one. One 500 watt plate amp pushing two 15" 8 ohm subs are going to kill almost any 3-way with a 15" woofer unless you have a 250 WPC amp (OUCH!), but it blows the budget too.

[OlderMongrel]

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

For any lurkers who like the idea but are willing to go bigger, take a look at this PRV 15 ($68.99; fs = 30, Qts = .59, Vas = 7.92 ft3)...

http://www.parts-express.com/prv-audio-15w700-15-high-power-pa-woofer-8-ohm--294-2740

12 ft3 sealed gets you down to 30 @ -6db. You can go vented, you can go smaller (more ripple of course). Then again you could run 2 in 24 ft3...for those of us in a position to regard ManCave and WAF as pertaining to separate magisteria.

John

[lorenmjones]

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

Do you like them?

I have the 8fe200's in my truck Loren if you are still in the area and want to audition/borrow.

[lorenmjones]

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

My phone battery is low so I don't have time to reply to each post.

Perhaps it makes the most sense to come up with a target for sensitivity and low-frequency extension and enclosure size then try to examine various woofers and low-frequency alignments in that context.

I feel like the concept fits for sensitivity in the 90 db plus or minus 2db range. I also would think enclosure of 100 liters net plus or minus 15 liters will work just fine with this form factor. Finally I would think LF extension of F3 below 40 sealed and around 30 vented would be great targets. I also think with the whole vibe of the design a goal of 108 db or higher sustained output (on paper at least) would be reasonable. I think nominal 8 ohm impedance would be a plus but perhaps not mandatory. I feel like 12" or 15" woofer is the way to go if just for the reason of aesthetics and feel. Plus big cones do bass well especially when the drivers are on the cheap side.

These are my thoughts. What does everyone think are the important targets?

[ngjockey]

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

Unfortunately, my calculator shows the DC380 coming up a bit a few shy of 40 Hz sealed and the DCS380 requiring a much bigger box, unless you want a Qtc around 0.9. Done 0.8 before with 6.5's and that wasn't bad. The DS315, ported, only requires about 2/3 that box and shows a F3 around 34 Hz but I haven't figured out how it models for a larger box. Wasn't that done already? Advantage there, either wider or shorter port