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3ll3d00d

Woofer for 40-250Hz?

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I'm looking for a woofer suitable for use in the ~40-250Hz range and that is comfortable in a relatively small enclosure and ideally could be used in either ~40L sealed or ~75L ported. Intended use is HT as the bottom end of the LCR but which will also receive that portion of the LFE (i.e. want to be able to try spreading the LFE down to this point across the LCR). Not too concerned about cost really.

Drivers I've modelled so far include

FaitalPro 15XL1400 - 15XL1400 by FaitalPRO
Beyma 15p80Nd - LOW & MID FREQUENCY 15P80Nd | Beyma
18sound 15nlw9401 - 15NLW9401
BMS 15n840 - Overview

Current favourite is the BMS. Any other suggestions or personal experience of such drivers appreciated.

 

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I don't have advice to give, except that my biggest concerns would be how clean these are at the upper frequencies.  Obviously, going with quality pro drivers goes a long way for that purpose.

Out of curiosity, will these be replacing one of your AE TD10s?  Or do you planning on turning the front speakers into 4-ways?  What made you decide you wanted more bass output above 100 Hz than you have?

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3 hours ago, SME said:

Out of curiosity, will these be replacing one of your AE TD10s?  Or do you planning on turning the front speakers into 4-ways?  What made you decide you wanted more bass output above 100 Hz than you have?

FWIW I am currently using a pair of TD12Ms for W/M though. The thought is to turn the fronts into 4 ways however it's not to add another driver beneath what I currently have, it's for a different speaker entirely.

I've wanted to try a synergy style horn for a while and there is a design out there which uses a SEOS15 for this purpose (http://www.diyaudio.com/forums/multi-way/292379-syns.html). I happen to have a bunch of SEOS15s in the house  so I thought I'd give it a whirl. This design is limited by the <200Hz region though as it uses a pair of 6s and I don't think it will be enough for me. I sketched out a 4 driver version (which will have pretty much as much capability my existing setup) but that box seems a little unwieldy.

The other option is to go 4 way (but not a 4 way passive, go active between the woofer and the horn) which then made me think why not go big enough to spread the LFE around to mitigate room issues.

Plan is to build one to try it out, if it works then build some more (as the first one will be donated to a local community choir for their rehearsals which is also one driver behind the desire to use something capable of running in a smaller sealed box as well as a larger ported box).

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Hmm, that is an interesting design.  The compact size is impressive.  It does look like it has a slight power response peak around 1 kHz due to the vertical pattern, but that may not be as bad as it looks by looking at the polars.  Still, I don't think it's really a perfect point source like a real Synergy would be.  I wonder if a dual-mid  version (top and bottom) would behave better?

FWIW, I'm using my SEOS-15 + DNA-360 down to 850 Hz now, with an 8th-order acoustic XO.  The baffle holds the woofer pattern quite well down to 500 Hz.  The DNA-360 doesn't go quite that low, but based on my response and THD measurements, I decided 850 Hz should be fine.  So I had a pretty wide range of XO frequencies suitable for horizontal pattern match.  However, when looking at the verticals, I noticed that the woofer was approximately the same as the horn right at around 850 Hz.  Above there it narrows more than the horn, causing a wider band power response dip than would be expected for just the XO, when the XO frequency is higher.  In order to further minimize the width of the dip and better protect the CD, I used an acoustic LR8.  By my estimates, the power response dips down to -3 dB between 700 and 1050 Hz (-1 dB points), and is very smooth outside there.  I'm tempted to try a 16th order XO eventually, to cut the bandwidth of the dip in half again, but that'll have to wait for another day.

Good luck!

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FWIW he recommends running a 4 mid version like a 3.5 way (by rolling off the top woofers) to minimise any negative impact on the vertical pattern. I have 2 problems with a full size synergy, one is size and the other is making the cuts to make the thing. I reckon it would be doable with my track saw though but probably one for the future. He does have a 3d printed version available that does mount the woofers on the horn itself, see http://www.diyaudio.com/forums/multi-way/307434-3d-printing-1-2-waveguide.html for details. 

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By "mids", do you mean the mids attached to the horn or the mids below the horn?  I don't see how one could attach 4 mids to the horn, so it must be the latter.  I'm not sure I understand how another pair of mids will solve that problem, even with a 3.5-way style XO.  I thought the comb-filtering of the horizontal pairing constrained how high those drivers could be run anyway.

The 3D printed approach is very cool.  I could see doing that someday but not for a long time.  I still haven't decided where and what I'm going to do with my 8X TD10X.  I have parts to build new surrounds, but I'm also thinking about various array options for those surrounds, rears, and/or ceiling speakers based on CBT.  I need to do some simulations to figure out what's possible and practical.

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I've built several AE PB18H+ sealed about the size of your desired ported sub size, but the larger woofer size helps out. 

91ddb4e6_212HT-LPLS-6.jpeg

 

 

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I have similar JTR 212 HT-LP and use the JBL 2226H drivers.  I actually bought a bunch of JBL 2226H drivers for a project I never got around to and need to put them on eBay.  Really impressive midbass in a pretty small cabinet though that AE cabinet looks pretty modestly sized for this board. :)

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On 05/02/2018 at 5:22 AM, SME said:

By "mids", do you mean the mids attached to the horn or the mids below the horn?  

sorry brain fail, you said mid and I replied talking about woofers. There is some discussion of an additional mid in the thread, conclusion is that there isn't a benefit and it is likely to make the HF response more ragged. He does put two on the 3d printed version but AIUI that is really to do the mechanics of printing it in 2 parts.

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17 hours ago, mojave said:

I've built several AE PB18H+ sealed about the size of your desired ported sub size, but the larger woofer size helps out. 

91ddb4e6_212HT-LPLS-6.jpeg

 

 

Nice looking builds. Do you happen to have an impedance measurement of the PB18H+?

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On ‎2‎/‎4‎/‎2018 at 2:08 PM, 3ll3d00d said:

FWIW he recommends running a 4 mid version like a 3.5 way (by rolling off the top woofers) to minimise any negative impact on the vertical pattern. I have 2 problems with a full size synergy, one is size and the other is making the cuts to make the thing. I reckon it would be doable with my track saw though but probably one for the future. He does have a 3d printed version available that does mount the woofers on the horn itself, see http://www.diyaudio.com/forums/multi-way/307434-3d-printing-1-2-waveguide.html for details. 

Thanks for that link. I hadn't seen this thread. Will read when I get time.

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Thanks for the suggested drivers. I'll have to discount them both though as I'm not prepared to spend time in the queue with AE on this occasion & the JBL looks like it will only work in the ported enclosure as well as being somewhat more expensive (in Europe) than any of the other options. Is there something about the JBL that makes it stand out from the BMS?

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Many people have used the JBL 2242H and 2226H drivers for midbass both sealed and ported.  They are solid drivers, easily available on eBay, but I don’t know there is anything that sets them apart from the BMS or AE, especially if they are more expensive or harder to get.  And I’ve also used the AE for midbass drivers and they are really nice too.

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The BMS should be really clean. You don't see them used much due to cost and difficulty of getting them in the US. Should be a great driver though.

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I've put together the cabinet for this (pretty simple sealed box) and run into a possible issue due to my depth constraint, if I stick to that constraint then I'm only going to have a shade under an inch (~23mm) clearance behind the pole vent. I estimate the diameter of that vent is ~60mm. I will not be running this really hard, well under rated power, so I have a feeling I can get away with this with no real negative impact (even if it's not ideal). 

Any views?

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I wouldn't worry.

I think the torture test would be to put on a concert BD with heavy mid-bass, crank it up to "call-the-cops" level for a few songs in a row, and then immediately due a sine sweep measurement.  Compare to a measurement when cold.  I bet you won't see any compression at all.

I've done the same sort of test with my TD12Ms, albeit with them crossed at 100 Hz but nevertheless driven hard enough by kick drum and electric bass to average several watts and repeatedly hit RMS peaks in the 50-100 W range.  Right afterwards, I touch the phase plug where most of the heat is radiated from, and it's completely cold.  They are rated at 500W RMS, so I shouldn't be surprised.

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actually it's probably more like 16mm or so clearance so a bit tighter than I thought, I guess I'll just have to buy one and give it a try to see what happens

I did start looking into 12" woofers (in order to find a shallower one) though anyway

the B&C 12NW76 (http://www.bcspeakers.com/en/products/lf-driver/12-0/8/12nw76) seemed somewhat on paper (shorting ring, seems like similar motor strength) albeit models with much more midrange(which I won't be using). I'm never quite sure whether to use xvar or xmax from the b&c specs though.

the BMS 12N804 (http://www.bmsspeakers.com/index.php?id=12n804_overview) was another one that looked promising

a comparison from hornresp models with EQ applied to use up the 200W on offer while keeping within xmax (vs the 15n840)

https://imgur.com/C3qXkV1

anyone with any views on any of these? (or any of the other 12" drivers for that matter)

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You might reconsider talking to AE.  They claim to have shorter lead times than they used to.  The TD15H mounting depth is 8" and does not require any clearance for vents.  The TD18 is 10".  The website says they have TD18H-8ohm ready for immediate shipment.  Too bad you probably prefer 4 ohm (?)

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