4 ohms opens it all up car audio as well:
like perhaps:
https://rockfordfosgate.com/products/details/pps4-8/
if you are using two drivers and worried about dispersion you could select low xmax high efficiency drivers and put a low pass filter on the second driver such that it is only active for the lower frequencies where the +6dB spl capability boost is required.
I've decided to run 2 x SB 6MW150D bass-mids in vertical arrangement, but placed next to (side of) the mid dome. I'll be crossing them within half wavelength of xover frequency in distance, so lobing won't be an issue in the horizontal plane. Details to follow...
If there's enough width for something like that, why not go to 12 inches? There are some 12 inch drivers that you can run up to 900 Hz as well. Or how about something like this?:
https://www.limmerhorns.de/042/
Best regards,
Michael
ATC - now I understand.
The best solution would be to use the T74A or B! There are plenty of posts about these drivers here and some measurements I took. I have both here. A picture of a prototype for special use (microphone measurements).
When you use the T34B and want the 8" up to 900 ... you use your mid dome from 900-1,5kHz? I REALLY would not do that!
The ATC 3" is used from 320-350Hz even in their big monitors, I use the Bliesma from 420Hz with passive crossover. You can easily get away with 3 way in this case - as does ATC.
I heared these big ATC monitors at AES conventions, e.g. recording competition. They are really able to fill a BIG room with sound. But the 3" can't deliver 125dBSpl. I calculated for the VOLT 3" 114dBSpl at their RMS limit, Bliesma M74B should be 118-119dBSpl. Peaks probably 2-3dB higher.
ATC has less sensitivity as the Bliesma but more Xmax for low frequencies. But for sure it doesn't get louder as the M74 in the midrange, would say 2dB less.
Would have been my 2nd suggestion, with DE360 it sounds for sure good and not PA like.
But you don't have the resolution of these Beryllium dome drivers ... but better controlled directivity and even more headroom.
Hmm, given this frame of reference; it takes one whole channel of this system just to go within 3-6 dB of 'live'.
Sad, but true as I'd 'been there, done that' trying to do same and it took a stereo pair of a full compression loaded corner horn system to achieve long before the internet/seeing this article.............
So, to try replying to the majority of responses, I'll keep things as pointed as possible.
The ATC setup we used for this project was showing its limitations exactly in the lower mids where the 3" dome mid ran out of acoustic steam. It couldn't do the 350 - 700 range at the same levels as the LF could dish out and you could hear the IMD of the mid go skyrocket. What was there within its limits sounded great and at least I had a reference of what was needed to accomplish the goals.
We did an experiment with recording a drum kit onto my daw and trying to see how close we got with playback over various speakers. I had a set of JBL SRX 835s which got closest to the dynamic levels of the live kit, but significantly lacked in resolution compared to the ATCs. The mids of the JBLs were their strong point, likely due to the horn loaded cone mid using their version of Audax PR170MO driver. Clearly, a horn loaded cone driver works best for this intended purpose, but it requires alot of engineering and simulation to get the best from compared to direct radiating mids.
I'm apprehensive to use a large cone midbass for the range (just shy of up to 900 - 1000 hz to allow for xover overlap) needed to not mechanically overload the 3" dome I plan on using. A decent 10" may work ok if the cone is shallow enough to keep it from beaming above roughly 600 hz and avoid its cone breakup range in the overlapping xover region to the mid. A decent 8" midbass would at least cover the 300 - 900 range without running into cone breakup in the passband, but finding one that has the specs needed at low distortion levels is proving tough. A good 10" may be the solution. I tried avoiding the use of multiple smaller drivers but may need to do so by means of shading the frequency ranges as some already mentioned.
The 3" dome I'm fabricating is from an SB acoustics compression driver using a composite Ti/PEEK diaphragm with polymer surround. The dome is being shimmed out a few thousands to allow for excursion without hitting the phase plug. I've already listened to it with a simple 6 dB HP filter and it clearly works much better than I expected. The main issue here is cost, as this is all being done on a tight budget considering the goals. I tried the Volt 3" dome and didn't like it compared to the ATC crossed at 600. Its a decent mid but not up to the standards needed here. I can't afford any of the Bliesma M74 domes, so they're not an option. The CD to dome mid conversion makes the most financial sense.
I wanted to use 2 of the Scanspeak D7608 domes per side, but even used in pairs they can't handle the output needed. Any of the other cheaper, budget large domes (Tang Band, Hivi) i don't even come close to the performance needed here. The main reason for using a large dome is the accuracy and resolution they have compared to cone drivers. I've yet to hear a smaller cone mid that can approach the clarity and finesse of a large dome. Hence the reason ATC, PMC, Neumann and others uses them in some of their larger studio monitors. I'm already spoiled having worked a bit with these monitors. I wish horns were an option, but I lack the funds and time for designing / using high end CDs and WGs.
The ATC setup we used for this project was showing its limitations exactly in the lower mids where the 3" dome mid ran out of acoustic steam. It couldn't do the 350 - 700 range at the same levels as the LF could dish out and you could hear the IMD of the mid go skyrocket. What was there within its limits sounded great and at least I had a reference of what was needed to accomplish the goals.
We did an experiment with recording a drum kit onto my daw and trying to see how close we got with playback over various speakers. I had a set of JBL SRX 835s which got closest to the dynamic levels of the live kit, but significantly lacked in resolution compared to the ATCs. The mids of the JBLs were their strong point, likely due to the horn loaded cone mid using their version of Audax PR170MO driver. Clearly, a horn loaded cone driver works best for this intended purpose, but it requires alot of engineering and simulation to get the best from compared to direct radiating mids.
I'm apprehensive to use a large cone midbass for the range (just shy of up to 900 - 1000 hz to allow for xover overlap) needed to not mechanically overload the 3" dome I plan on using. A decent 10" may work ok if the cone is shallow enough to keep it from beaming above roughly 600 hz and avoid its cone breakup range in the overlapping xover region to the mid. A decent 8" midbass would at least cover the 300 - 900 range without running into cone breakup in the passband, but finding one that has the specs needed at low distortion levels is proving tough. A good 10" may be the solution. I tried avoiding the use of multiple smaller drivers but may need to do so by means of shading the frequency ranges as some already mentioned.
The 3" dome I'm fabricating is from an SB acoustics compression driver using a composite Ti/PEEK diaphragm with polymer surround. The dome is being shimmed out a few thousands to allow for excursion without hitting the phase plug. I've already listened to it with a simple 6 dB HP filter and it clearly works much better than I expected. The main issue here is cost, as this is all being done on a tight budget considering the goals. I tried the Volt 3" dome and didn't like it compared to the ATC crossed at 600. Its a decent mid but not up to the standards needed here. I can't afford any of the Bliesma M74 domes, so they're not an option. The CD to dome mid conversion makes the most financial sense.
I wanted to use 2 of the Scanspeak D7608 domes per side, but even used in pairs they can't handle the output needed. Any of the other cheaper, budget large domes (Tang Band, Hivi) i don't even come close to the performance needed here. The main reason for using a large dome is the accuracy and resolution they have compared to cone drivers. I've yet to hear a smaller cone mid that can approach the clarity and finesse of a large dome. Hence the reason ATC, PMC, Neumann and others uses them in some of their larger studio monitors. I'm already spoiled having worked a bit with these monitors. I wish horns were an option, but I lack the funds and time for designing / using high end CDs and WGs.
For 8 inch look at JBL2118H
For 10 inch look at JBL2123H
for these "large" mid drivers X-Max is not an issue. Pluss distortion is very low.
For 10 inch look at JBL2123H
for these "large" mid drivers X-Max is not an issue. Pluss distortion is very low.
FWIW, etc., Altec's measurements show basically no difference between Altec's 'deep' cone Vs JBL's 'shallow' one and a 10" is > 160 deg (Vs the 180 deg theory) to ~1200 Hz.
The 8NDL51 is definitely available in 4 ohm;
https://www.bcspeakers.com/en/products/lf-driver/8-0/4/8ndl51-4
https://www.bcspeakers.com/en/products/lf-driver/8-0/4/8ndl51-4.pdf
The 8NW51 is a lot more efficient and also available in 4 ohm
https://www.bcspeakers.com/en/products/lf-driver/8-0/4/8nw51-4
I am also confused what kinda numbers you're looking at, because most of those woofers will do a lot of SPL with very little cone excursion when being crossed around 300Hz.
They will be all power limited, not excursion limited, since the Fs is way to low for that.
The 8NW51 with a sensitivity of 97dB/W will give you a theoretical limit that is very close to that 120dB line.
B&C are great woofers, very robust, 8NW51 is great as well.
I don't know what the goal is, but in a serious environment really recommended.
Eighteensound has a couple of 4 ohm 8 inch woofers as well.
Last edited:
If it needs to go that loud and you can cross around 300-400Hz, I would rather suggest going for those B&C or BMS coax compression drivers.
Hello,
Horns have more and different distortions. They sound like horns.
Large efficient cone drivers have in the range of 20 dB's lower distortion at typical SPL's.
Save the horns for 2kHz and up.
Thanks DT
At those sound pressure levels, especially when being used for long periods of time, little differences in distortion are absolutely one of least things of your worries.
I also don't know what you mean with "the sound of a horn"?
Depending on the dimensions of the horn, they can have a higher directivity. Which is in these super high SPL environments rather a good thing than a bad thing.
In general I would advise a line array probably sooner.
Last edited:
BTW, I also don't completely agree with the claim that the distortion of a woofer would be better.
Unfortunately we don't have any numbers at does maximum levels.
But at lower levels these coax CD's perform extremely well.
Especially with the lack of odd harmonics. Also take note of their sensitivity and what that means for the power consumption and dissipation.
https://audioxpress.com/article/tes...igh-power-coaxial-compression-driver-and-horn
https://audioxpress.com/article/test-bench-bms-4507nd-dual-diaphragm-coaxial-planar-wave-driver
In general a 8 inch wouldn't be my advice for this purpose.
But we still don't really know the entire context, so it's hard to give any proper advice.
Unfortunately we don't have any numbers at does maximum levels.
But at lower levels these coax CD's perform extremely well.
Especially with the lack of odd harmonics. Also take note of their sensitivity and what that means for the power consumption and dissipation.
https://audioxpress.com/article/tes...igh-power-coaxial-compression-driver-and-horn
https://audioxpress.com/article/test-bench-bms-4507nd-dual-diaphragm-coaxial-planar-wave-driver
In general a 8 inch wouldn't be my advice for this purpose.
But we still don't really know the entire context, so it's hard to give any proper advice.