Another vote for 15" midbass like Lambda TD15M.
A commitment to a large SEOS24 is a rare opportunity to experience effortless dynamics and smooth controlled directivity. There are a few magic 15" wide bandwidth midbass drivers like the 98db/watt Lambda TD15M that can deliver this promise. A 3.2cuft sealed box will reach -3db at 75Hz. This frequency will allow both shared-box woofers and remote box woofer options.
--Diffraction control requires large radius/mitered edges.
--The SEOS24 is 8" deep before the compression driver. Requires time alignment in analog/digital Xover, or 2slope passive.
--Sealed box woofers require less volume and provide greater Xover and room equalization options.
A commitment to a large SEOS24 is a rare opportunity to experience effortless dynamics and smooth controlled directivity. There are a few magic 15" wide bandwidth midbass drivers like the 98db/watt Lambda TD15M that can deliver this promise. A 3.2cuft sealed box will reach -3db at 75Hz. This frequency will allow both shared-box woofers and remote box woofer options.
--Diffraction control requires large radius/mitered edges.
--The SEOS24 is 8" deep before the compression driver. Requires time alignment in analog/digital Xover, or 2slope passive.
--Sealed box woofers require less volume and provide greater Xover and room equalization options.
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That would definitely sound different than the paper variety. Another similar choice is 10" discovery series from Scanspeak.
If you need more gain and can "spend" the volume requirements there are these:
http://www.madisoundspeakerstore.com/pro-sound/audax-pr240m0-professional-10-woofer/
I'd personally stick to the 3-way and make your mid.s a VERTICAL line between a "square" placement of four 8" drivers. The "mid.s" could even be mid-bass drivers and the 8" drivers could be "subs".
Note that the SEOS (especially when driven down near its "cut-off") is pretty much an infinite baffle response at those freq.s where you would crossover - similar to a smaller radiator on a large baffle.
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The problem (maybe?) with 15"s for the mids is that my primary listening distance is rather close at ~65"s, so I'm trying to keep the center to center spacing under control. The other problem is it would require that I rebuild the subs (which are already done and sound great). As it would put the SEOS a little too high.
Diffraction control here handled by being corner horns, effectively soffit/wall mounted once in position. Ideally when I build a bigger control room down the road I will extend the 45 degree wall surface further to the sides as well, and possibly investigate a smooth transition there. Also though, it can be placed in broadband absorbers (as it is now, 4" 703 on the walls there), to further mitigate this.
I think at some point with the 24s it's a question of true large format capability and a higher XO point, or more of a "domestic mid format" ability, because with a 500hz crossover point throat compression becomes an issue at some level. I've done some comparisons and for my needs the lower XO point is a worthwhile trade off...No need to reach into the 130dB range. To that end I tend to think anything that can match the point where throat compression starts can match the overall system dynamics. In a large format PA, no doubt a higher XO, further listening distance, and a TD15M would be the only way to go.
Regarding delay to adjust timing, interestingly I get the deepest reverse null not using it...not sure why as the NS6's are pretty shallow. I'm using 48dB/oct now though, changing to 24 didn't seem to make a big difference there.
Thanks though it's always helpful to keep my rusty gears turning...
How would you describe the difference there between paper/carbon fiber in this range?
The 4 8"s is an interesting idea, but all the polars on SEOS that I have seen show they hold pattern below what is stated on the DIYsoundgroup page...I do already have those W15gti subs done, anything taller than 10 or maybe 12 would require rebuilding them. The JBL's really suit my purposes for the deep stuff and even to smooth the modal region.
Just a thought here too-
Many audiophile types (nevermind the pejorative connotation for a sec), have the luxury of picking music that their system is well suited for.
I have to keep ROI in mind, in the sense that at least being able to have that slightly-sick-to-your-stomach bass makes rappers especially reach for their wallets.
Then I can turn it down, take out my earplugs and get back to work. In any case right now the system sounds great from Young Jeezy to Brad Mehldeau. Especially the SEOS and the W15gti's, the NS6 definitely run out of gas a bit too soon.
Thanks guys, kinda specific/different needs here so I appreciate your patience with me.
Many audiophile types (nevermind the pejorative connotation for a sec), have the luxury of picking music that their system is well suited for.
I have to keep ROI in mind, in the sense that at least being able to have that slightly-sick-to-your-stomach bass makes rappers especially reach for their wallets.
Then I can turn it down, take out my earplugs and get back to work. In any case right now the system sounds great from Young Jeezy to Brad Mehldeau. Especially the SEOS and the W15gti's, the NS6 definitely run out of gas a bit too soon.
Thanks guys, kinda specific/different needs here so I appreciate your patience with me.
Hey ScottG that Audax is very interesting. The boxes here can be quite large ~7 cubic feet is definitely possible. How conservative do you think the xmax rating on those are? Very nice sensitivity, do you have any experience with them?
I'm going to model that in WinISD when I get to my PC at home, thanks-
I'm going to model that in WinISD when I get to my PC at home, thanks-
If you can afford it, do it. I also wouldn't be surprised if you later find the W15GTIs to limit you.
Serious question: what about the JBL W10GTi? Should go a bit higher than the W15 (though I only have direct experience with the W15), has that amazing motor, fairly efficient, and lots of wiring options.
As someone with experience running the W15GTi, I would. Literally the only thing wrong with the driver is the tacky tacky dustcap. Otherwise, I'd say they're directly comparable with the Aurasound drivers.
As someone with experience running the W15GTi, I would. Literally the only thing wrong with the driver is the tacky tacky dustcap. Otherwise, I'd say they're directly comparable with the Aurasound drivers.
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HAHAHA!!! Rolling. Yes the plastichrome dust cap is hideous. I was lucky to find some of the old mkI's ones that don't have any tensile slap issues for the 15's.
This is a very good idea, one I have considered and even scoured the internet looking for some of the MK1's. It is definitely something to ponder, it certainly it would fit the bill. 92dB from a sub is very good and the Le is the best of perhaps any true sub (up there with aura at least).
Hmmm...black spray paint?
I too have a very hard time faulting this driver, usually when you solo subs they sound like crap, the 15's are very clean, I could also do a little dance with a first order high pass to keep excursion under control.
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Output, though I guess you could say a driver is always going to be limited in SPL when you take a certain amount of SQ degradation as your limit.
See the Klippel results here: Car Audio | DiyMobileAudio.com | Car Stereo Forum
There is nothing special about this motor except that the inductance is not bad and the Xmax is pretty good for a pro driver of this size. When JBL was developing DD, they really missed out on the opportunity to straighten out the BL curve just by offsetting the coils a little bit. They probably would've been able to do it while even sidestepping XBL2 patents because they use two gaps instead of one. 18 Sound has their Tetracoil technology now too. Poor JBL.
Well, I guess there isn't much to complain about this driver except that it had a lot more potential.
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If you're listening nearfield and the listening position doesn't change, the polar response (affected by CTC) doesn't really matter because the nearfield response will dominate the indirect response from the room.
I would also suggest going with a single 15" mid and a bigass 18" (multi, or bigger) vented on the bottom. Would going with a 15" mid negatively impact the height of the WG?
Generally improved clarity for hard-cones over paper.
What you are missing is that almost any standard driver at a wavelength longer than the cone's diameter while on an INFINITE BAFFLE will act almost the same as the 24" SEOS. Basically at +/- 45 degrees a driver on that sort of baffle experiences a very similar loss in pressure (see the polar plot below).
It's only when you move lower in freq. relative to the baffle that the pattern "narrows-up". The larger the baffle, the lower the freq. you can run a driver and achieve a very similar polar pattern.
In the measurements below, the baffle is responsible for the narrowing pattern below 375 Hz. It's at that freq. where the baffle no longer is considered "infinite".
The midrange line would look similar.
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No experience. But I do have some experience with other Audax drivers.. only average on non-linear distortion.
x-max is probably close to +/- 4mm.
7 cubic feet would give you a Qtc of about .9, with good extension to about 60 Hz and close to your typical sealed box roll-off from there.
Still, I'd recommend 4 mid.s and 4 mid-bass's.
Ah, (I think) I'm following you now.
Jake's (got my 24's from him) box there is ~26" wide, so what you are saying is that the point at which the wavelength excedes the baffle width, and the radiation becomes omni (baffle no longer infinite WRT wavelength?), the "beaming" of the woofer is is governing the directivity matching less, and the size of the baffle is governing it more?
So in my case with the baffles straddling the corners of the room (albeit walls are covered with 4" rockwool), the baffle is effectively infinite or at least functioning that way until we get down much lower? Hopefully around/near schroeder freq...
I'm having a hard time visualizing the placement of the 4 mids and the 4 mid basses that you are suggesting...and then you are also suggesting to get rid of the subs?
Thanks for the help and sorry for being slow on this...
That's about right.
While you could get rid of the sub.s, I wouldn't - it was just something that could be done or what's possible with your large volume and active crossover/power amp design.
Ex.
Picture: (the ".." means that space is part of the 8" driver):
S E O S
8" 4" 8"
.." 4" .."
8" 4" 8"
.." 4" .."
You could also split the grouping with the SEOS in the middle, but that would require a steep crossover (that's at least as low in freq. as 600 Hz). (..it's a combing issue with the 4" line split, also - the 4" split-line won't have has much gain as the example above.)
Perhaps the Vifa TC9FD18-08 and the SB Acoustics SB23NRXS45-8 with a crossover near 300 Hz (or whatever best coincides with the baffle-step loss area for your baffle).
Vifa:
http://www.zaphaudio.com/temp/Vifa-TC9FD18-08-FR.gif
http://www.zaphaudio.com/temp/Vifa-TC9FD18-08-HD.gif
http://www.zaphaudio.com/temp/Vifa-TC9FD18-08-CSD.gif
http://www.zaphaudio.com/temp/Vifa-TC9FD18-08-TS.gif
SB:
http://www.zaphaudio.com/temp/SB-Acoustics-SB23NRXS45-8-FR.gif
http://www.zaphaudio.com/temp/SB-Acoustics-SB23NRXS45-8-HD.gif
http://www.zaphaudio.com/temp/SB-Acoustics-SB23NRXS45-8-CSD.gif
http://www.zaphaudio.com/temp/SB-Acoustics-SB23NRXS45-8-TS.gif
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Very interesting-
That jives with measurements (haha duh). I had chalked it up to other room artifacts/interactions, but with the current setup definitely off-axis there is more coming off the NS6's then there is coming off the SEOS @45 degrees off axis. Also jives with listening off axis. The constant directivity thing only really fooling the brain into hearing a balanced image off axis for sounds are entirely above 500hz.
I could do up to nearly infinite dB/oct by stacking 48dB/oct filters, I'm wondering would this work as well with the whole thing upside down? IE all the 4/8 woofers on top of the seos? Subs on the bottom, SEOS between. That would give plenty of space to optimize the horn height and not rebuild the subs. Moving the subs up has improved the sound because otherwise the desk blocks them (on the floor), making them only usable for the deepest stuff.
I have 8 ch volume control and dac available for the speakers and other amps I could use until I added another stereo hypex for the 3rd way.
I'm assuming the 4" drivers would also need a separate rear chamber from the 8"s?
The boxes are triangles so the baffle straddles the wall/wall corners, it's 32" wide (can't tell if that is obvious from the pic or not).
Thanks Scott this is very helpful.
That jives with measurements (haha duh). I had chalked it up to other room artifacts/interactions, but with the current setup definitely off-axis there is more coming off the NS6's then there is coming off the SEOS @45 degrees off axis. Also jives with listening off axis. The constant directivity thing only really fooling the brain into hearing a balanced image off axis for sounds are entirely above 500hz.
I could do up to nearly infinite dB/oct by stacking 48dB/oct filters, I'm wondering would this work as well with the whole thing upside down? IE all the 4/8 woofers on top of the seos? Subs on the bottom, SEOS between. That would give plenty of space to optimize the horn height and not rebuild the subs. Moving the subs up has improved the sound because otherwise the desk blocks them (on the floor), making them only usable for the deepest stuff.
I have 8 ch volume control and dac available for the speakers and other amps I could use until I added another stereo hypex for the 3rd way.
I'm assuming the 4" drivers would also need a separate rear chamber from the 8"s?
The boxes are triangles so the baffle straddles the wall/wall corners, it's 32" wide (can't tell if that is obvious from the pic or not).
Thanks Scott this is very helpful.
Your welcome!
Yes, upside down would be fine, and likely preferable.
Yes, 4" drivers would definitely need their own chambers..
FWIW-
I can freely configure the active crossover (PCXO freely routable). IE the 8's could be LPF'd (1st order presumably?) @~100hz fed from the same buss that LPF's the 8's and the 4's as a group at 500hz at 8th (or 16th or 32nd etc) order.
The only caveat is sh*t happens in the studio so I feel much more comfortable with at least 12dB/oct HP for the CD's being passive (or at least analog domain pre amps). Especially because replacing the diaphragm is not only expensive but represents a loss of income.
FIR eq's aren't really a viable option. I have them but the latency makes them too problematic in 99% of scenarios.
I can freely configure the active crossover (PCXO freely routable). IE the 8's could be LPF'd (1st order presumably?) @~100hz fed from the same buss that LPF's the 8's and the 4's as a group at 500hz at 8th (or 16th or 32nd etc) order.
The only caveat is sh*t happens in the studio so I feel much more comfortable with at least 12dB/oct HP for the CD's being passive (or at least analog domain pre amps). Especially because replacing the diaphragm is not only expensive but represents a loss of income.
FIR eq's aren't really a viable option. I have them but the latency makes them too problematic in 99% of scenarios.
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