The driver I linked on the first page is actually new Altec stuff not old, made by GPA with the old original Altec tooling and recipes etc...
Great Plains Audio's Homepage
I am very interested in this thread. I am looking for the same thing. I have great FR and SPL from 20-50hz, but need something to fill in the mid-bass accurately from 50hz-300hz. With a line array (ie 2-10's or 12's) at these frequencies, does comb filtering still play a factor in the timbre of sound on-axis or off?
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Instead of the TD15 lambda series from AESpeakers.com. Maybe people should consider the AV15X instead.
It will definitely go down below 20Hz and still have good effeciencies because its a great subwoofer (One of the best 15" right now!!).
The other bonus is that these amazing drivers play well way up into the 500Hz range. Dual opposing AV15X will give you a great bass bin that will play from 30Hz to 600Hz!!
It will definitely go down below 20Hz and still have good effeciencies because its a great subwoofer (One of the best 15" right now!!).
The other bonus is that these amazing drivers play well way up into the 500Hz range. Dual opposing AV15X will give you a great bass bin that will play from 30Hz to 600Hz!!
I am very interested in this thread. I am looking for the same thing. I have great FR and SPL from 20-50hz, but need something to fill in the mid-bass accurately from 50hz-300hz. With a line array (ie 2-10's or 12's) at these frequencies, does comb filtering still play a factor in the timbre of sound on-axis or off?
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I love the TD12S drivers from aespeakers.com for 50Hz to 500Hz! I have never had better mid bass slam in my HT.
What max SPL do you need, what amps do you have? Sensitivity should only be a conditional spec based on actually requirements.
IE...a 92dB driver can play above 120 dBs just as well as a 99dB driver. It just needs more power. I give my TD12S, 500Watts each...lots of headroom, heck I never remotely hit their max SPL peaks.
SBP15s? Is that a new AE design.
THe AV series are really subwoofer drivers, with great low extension because of their displacement but John J has shown measurements all the way up to 1KHz that impressed me.
The TD series are woofers used in main speakers. They can extend low into the 30Hz range for full range speakers (X, S, H series) or they can play well all the way up to 1500Hz (M series) but not have the low end without a PORTED design (Fs around 120Hz)
btw, why stop at 15", the new TD18H is sick!!!! (it has a 2.5" coil).
T/S Parameters:
FS: 29.0Hz
Qts: 0.22
Vas: 390L
Z: 8ohm
1WSPL: 98.2dB
Pe: 1000W continuos
18" plus 14mm xmax would create some displacement and the 98dB is a nice start....put 1000W into WinISD and see the numbers
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SBP15 is an old paper coned subwoofer. It reaches lower than the TD15s in slightly larger boxes and has a more conventional looking dustcap. Regarding the 18, it is too sensitive and too big for my needs and doesn't offer the extension. I agree that it does look cool though.
Parameters for the SBP15 are as follows. This is for the 4ohm version. 8ohm is available also:
Fs: 21.3Hz
Qms: 5.35
Vas: 364L
Cms: .35mm/N
Mms: 160g
Rms: 4kg/s
Xmax: 18mm
Sd: 855sqcm
Vd: 3.08L
Qes: .47
Re: 2.7ohm
Le: .3mH
Z: 4ohm
BL: 11.1 Tm
Qts: .43
1wSPL: 90.7dB
Parameters for the SBP15 are as follows. This is for the 4ohm version. 8ohm is available also:
Fs: 21.3Hz
Qms: 5.35
Vas: 364L
Cms: .35mm/N
Mms: 160g
Rms: 4kg/s
Xmax: 18mm
Sd: 855sqcm
Vd: 3.08L
Qes: .47
Re: 2.7ohm
Le: .3mH
Z: 4ohm
BL: 11.1 Tm
Qts: .43
1wSPL: 90.7dB
Cool, never knew about that one.
I have many TD series drivers and the AV15X. I really want to swap out one of my TD bass bins and try the AV15X up to 400Hz.
Here is a very good paper about line arrays:
http://www.audioroundtable.com/misc/nflawp.pdf
According to my calculations the sensitivity gain in one meter distance is 10 Log (2 meters / driver distance) and the given formula 10 Log (number of drivers used) is only true for a typical height of 2 meters, but I think the rest is correct.
Using Cabinet for Hi-Pass filter?
My thinking is that a efficient 15" driver in a sealed box of about 80 litres would give the same inital roll off as a second order butterworth filter tuned to 65Hz.
I have used a Fane XB 15" driver in this sim.
Extended response is a 170 litre reflex cab (would quickly run out of X max!)
red plot is the same with a 2nd order hi-pass butterworth @65hz.
Yellow plot is a sealed 80 litre box.
Bear, what sort of low pass crossover would be used on the sub?
My thinking is that a efficient 15" driver in a sealed box of about 80 litres would give the same inital roll off as a second order butterworth filter tuned to 65Hz.
I have used a Fane XB 15" driver in this sim.
Extended response is a 170 litre reflex cab (would quickly run out of X max!)
red plot is the same with a 2nd order hi-pass butterworth @65hz.
Yellow plot is a sealed 80 litre box.
Attachments
Xoc1,
I use a 24db/oct xover on the top end of the sub.
The idea is to let the low end of the "filler" roll itself off... non-ideal I understand, but it's not terribly significant imho and adding in a HP to the "filler' driver is always an option... I physically align the drivers for the best impulse response (the initial spike adds).
If I were to do the LP for the sub again, I'd use a completely different sort of filter, but that's a story for another time. I have the 4th order box.
_-_-bear
I use a 24db/oct xover on the top end of the sub.
The idea is to let the low end of the "filler" roll itself off... non-ideal I understand, but it's not terribly significant imho and adding in a HP to the "filler' driver is always an option... I physically align the drivers for the best impulse response (the initial spike adds).
If I were to do the LP for the sub again, I'd use a completely different sort of filter, but that's a story for another time. I have the 4th order box.
_-_-bear
...entirely possible, but they have somewhat limited power handling... not withstanding their use in guitar amps...
It is a fine driver... but may extend too high and have some peakiness due to the aluminum dustcap. All things that could be overcome... I am considering them, btw.
_-_-bear
I honestly think its a slam dunk. When I thought of 100db 15" woofer and didn't consider current offerings only it jumped to the top of the list in my head. I would throw a kilowatt Crown or Lab Gruppen at it, but it isn't for that.
Danny McKinney uses them in his Standel amps as they were used originally. (and they are bitchin)
Chris
Danny McKinney uses them in his Standel amps as they were used originally. (and they are bitchin)
Chris
There's more to it than just the "ability" to play at high SPLs... for reasons that are not entirely clear to me they don't seem to sound quite the same. Perhaps the reason is that there is a difference in distortion or harmonics produced by an "efficient" motor being run at lower power as compared to a "normal" motor being run at highish power. Dunno really.
Also, you loose the option of using amps that are "more subtle" - being lower power from tubes or class A solid state and must use high power SS amps then. That too changes the subjectively received sonics...
My horns are 109db/1w/1m... staying within the 10dB "window" gives me a nice option of using the Pass F5 with ~15db gain vs. my Symphony No.1 amp (see my website...) at ~26db gain and having a "magic" match.
I don't really want to play anything at 120dB, ever - I want uncompressed peaks when the source material has peaks of 20+dB. Imho that's one of the things that makes things sound effortless and natural.
So, if we're at an average of ~93dB SPL at the listening position which is 6-9meters from the speakers, and we need 20+dB of headroom, you can start to see what the requirements really are.
Few systems can really dish this out without clipping the amps or reaching the dynamic limits of the speakers (and/or getting significant non-linear distortion).
No doubt some of these newer high power woofers represent an interesting solution, but do require very high power amplifiers and at least I have reservations about how those amps might sound in this range. (it might be fine... fwiw)
_-_-bear
Nice paper...
for this application, a "filler" woofer from ~65 - ~300Hz., the game is somewhat different than the wide range line array that is the design goal of the paper.
We do get some gain in sensitivity with a series paralleled array of drivers, that's good. But we end up with using a lot of drivers whose performance is still the same as a single driver. To get a single driver that is good enough in that range and also starts out with >90db SPL/1w/1m and has any real power handling is not likely to be an inexpensive driver!
Take a look at my website, under "Archives" and look for the CVSR. That was ~1976 and those were Peerless 5.25" drivers. It took a Phase Linear 700 to make it rock. Super power for that day. It's also a relatively huge box.
Most small drivers tend to have highish Fs, in the 50 - 70hz. range, which depending somewhat upon Qt will be difficult to get flat down to that range...
When ur all done, in the range we're talking about, I think a modern 15" driver will be more robust, more sensitive and likely have similar or better output SPL capability... but it would be nice to identify a small driver that could be used in an array of some sort for this application.
_-_-bear
Very good article, thanks, I have been looking for something like this.
It didn't talk much about the negatives of line arrays, such as some peoples perception of exaggerated height with vocals and there was no discussion on open baffle line arrays, which I am also curious about.
...Now back to the search for the "Best" woofer for 50hz-300. Can someone suggest an inexpensive, well performing woofer for this application? Would this be of the Eminence stock?
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