Where can I get a raw driver for a Giant Subwoofer? I'm talking about something that has a very low free space resonance. Some pipe organs go real low. Both the Radio City Music Hall one and the Wannamaker's one have 64' stops. This means they have the C note two octaves below the lowest C on a piano. Its about 8hz.
Some would say this is not sound. I don't know. But I want to experiement. I want to make a large built in subwoofer with a highpower amp hardwired to 220VAC.
I have heard rumors of 32" and even 60", and of frequencies as low as 5hz.
What raw drivers do you know of bigger than 15" or 18", and with very very low free space resonances.
I think this an ideal feature in a media room.
You can get away with this so long as you cross over low enough, and the rest of the program material goes to your channel speakers, and if your channel speakers go low enough themselves.
Think of this as an InfraWoofer.
Who knows of giant raw drivers?? How much $$$? Specs? Anyone else done anything like this?
Some would say this is not sound. I don't know. But I want to experiement. I want to make a large built in subwoofer with a highpower amp hardwired to 220VAC.
I have heard rumors of 32" and even 60", and of frequencies as low as 5hz.
What raw drivers do you know of bigger than 15" or 18", and with very very low free space resonances.
I think this an ideal feature in a media room.
You can get away with this so long as you cross over low enough, and the rest of the program material goes to your channel speakers, and if your channel speakers go low enough themselves.
Think of this as an InfraWoofer.
Who knows of giant raw drivers?? How much $$$? Specs? Anyone else done anything like this?
Fostex has a GIANT woofer.
http://www.fostexinternational.com/docs/speaker_comp/pdf/fw800n.pdf
I think Clarion also has a similar sized behemoth.
http://www.fostexinternational.com/docs/speaker_comp/pdf/fw800n.pdf
I think Clarion also has a similar sized behemoth.
You don't need that size woofers to get to 8 hz. I think you need something like Bagend-woofers (www.bagend.com)
Have fun
Thomas
Have fun
Thomas
With a correctly designed large format basshorn you can go an entire octave below the drivers fs without pushing it beyond xmax even at full power.
I have not any experience with other subwoofer systems than horns, but I would guess that a small bandwith helmholtz resonator system could be designed with the right amount of acoustic impedance to do a similar job one octave below fs.
Maybe someone has done some research on the subject?
If this could be a solution it should be possible to reach your 8Hz goal with ordinary 18" carwoofers with an fs of 16Hz.
The larger exotic woofers tend to be very expensive compared to the results you get.
I have not any experience with other subwoofer systems than horns, but I would guess that a small bandwith helmholtz resonator system could be designed with the right amount of acoustic impedance to do a similar job one octave below fs.
Maybe someone has done some research on the subject?
If this could be a solution it should be possible to reach your 8Hz goal with ordinary 18" carwoofers with an fs of 16Hz.
The larger exotic woofers tend to be very expensive compared to the results you get.
skramstad
Thank you. As I know, you really can't go below Fs. Of course the speaker cone will still move. But the efficiency goes to almost zero.
Any enclosure only raises such resonance. This applies to both front and back loading. So it applies to horns. It applies to transmission line enclosures, everything.
This is my understanding. So, please elaborate.
tlmadsen
thank you for telling me about bagend. It is interesting. They seem to be using somekind of a feed back approach. That is, you use something else to tell where the cone of the speaker is, or at least how fast it is moving.
I've heard of this being done with a laser beam reflecting off of something near the center.
I've heard of this being done with a second voice coil used to sense velocity.
I believe that Bagends INFRA technology must be something like this. I couldn't see on their web page a specific description.
A company in San Jose, Velodyne, makes something like this. I think their subs go down way below Fs.
This is another way to do it.
I'd like to explore all the posibilities.
Mikael
I looked at the Fostex driver. Giant it certainly is, 31"
They say it goes to 18hz. Not bad, but I'd like to try and go lower.
Of course a driver that big should be crossed over much lower than say a 12" or 15". But that is ok.
Any ideas about cost?
Any body got any other ideas in general?
Thank you. As I know, you really can't go below Fs. Of course the speaker cone will still move. But the efficiency goes to almost zero.
Any enclosure only raises such resonance. This applies to both front and back loading. So it applies to horns. It applies to transmission line enclosures, everything.
This is my understanding. So, please elaborate.
tlmadsen
thank you for telling me about bagend. It is interesting. They seem to be using somekind of a feed back approach. That is, you use something else to tell where the cone of the speaker is, or at least how fast it is moving.
I've heard of this being done with a laser beam reflecting off of something near the center.
I've heard of this being done with a second voice coil used to sense velocity.
I believe that Bagends INFRA technology must be something like this. I couldn't see on their web page a specific description.
A company in San Jose, Velodyne, makes something like this. I think their subs go down way below Fs.
This is another way to do it.
I'd like to explore all the posibilities.
Mikael
I looked at the Fostex driver. Giant it certainly is, 31"
They say it goes to 18hz. Not bad, but I'd like to try and go lower.
Of course a driver that big should be crossed over much lower than say a 12" or 15". But that is ok.
Any ideas about cost?
Any body got any other ideas in general?
Efficiency going to almost zero is a bit of an exaggeration but you will need lots of power to go significantly below Fs.
Take a look at Servo-Drive subs - at one point there was some DIY support, but I think Tom is strictly commercial now. Tom used something like this for sonic boom simulators for the USAF, IIRC.
If your room is fairly small and solid, you can gets lots of low end boost from room effects like the car guys do. Sprinkle some low Fs 18" drivers liberally around a room with four concrete walls and a concrete floor and and enjoy.
I'm in the mid teens in room with a pair of JBL2245Hs in a quasi 6th order alignment tuned to 20 Hz (the driver's Fs) 500W each is enough for over 105 dB. The cannons on Telarc's 1812 Overture CD sound quite realistic. (supposedly lots of info down to 5 Hz.)
Take a look at Servo-Drive subs - at one point there was some DIY support, but I think Tom is strictly commercial now. Tom used something like this for sonic boom simulators for the USAF, IIRC.
If your room is fairly small and solid, you can gets lots of low end boost from room effects like the car guys do. Sprinkle some low Fs 18" drivers liberally around a room with four concrete walls and a concrete floor and and enjoy.
I'm in the mid teens in room with a pair of JBL2245Hs in a quasi 6th order alignment tuned to 20 Hz (the driver's Fs) 500W each is enough for over 105 dB. The cannons on Telarc's 1812 Overture CD sound quite realistic. (supposedly lots of info down to 5 Hz.)
zenmasterbrian said:Mikael, I've heard rumors about Clarion. Some years ago someone from Cerwin-Vega told me. But I can't confirm it. They say the drivers are made by mitsubishi, and that they are used for car audio competitions.
Of course I have no interest in such car audio.
I'll look at your other link.
I am using the 32" Clarion woofer in my DIY dipole Sub.
FS is about 17 HZ
I am using it up to 80 Hz max.
The normal speakers (DIY) are 5 http://www.metrum-acoustics.nl/ dipole hybrid ESL's with 2 scanspeak woofers.
Verry good and deep bass.
This is basically the circuit used by BagEnd:
http://v3.espacenet.com/origdoc?DB=...481662&DOC=dcb65d04ab6621e0985512cb934bf2c269
Regards
Charles
http://v3.espacenet.com/origdoc?DB=...481662&DOC=dcb65d04ab6621e0985512cb934bf2c269
Regards
Charles
Hi Zenmasterbrian,
I did not say that you cannot go below fs, but that you can go an entire octave below fs without loosing efficiency or reach out of the xmax limits. This is the fact with large format horns with high acoustic impedance (not the small 1 cubicmetre boxes, and my toughts was that this maybe should be possible to do with helmholtz resonator systems of small bandwith (6. order?). But as I have never made such boxes I was wondering if someone else has done some calculating on the subject?
I guess that you cannot add enough mass (air) in such a box of mobile size, but maybe the ports could be designed to have enough resistance to control the driver?
The Bag end patent seemed interesting. Anyone who have tested them? How loud are they below 20Hz?
I did not say that you cannot go below fs, but that you can go an entire octave below fs without loosing efficiency or reach out of the xmax limits. This is the fact with large format horns with high acoustic impedance (not the small 1 cubicmetre boxes
, and my toughts was that this maybe should be possible to do with helmholtz resonator systems of small bandwith (6. order?). But as I have never made such boxes I was wondering if someone else has done some calculating on the subject?I guess that you cannot add enough mass (air) in such a box of mobile size, but maybe the ports could be designed to have enough resistance to control the driver?
The Bag end patent seemed interesting. Anyone who have tested them? How loud are they below 20Hz?
http://sound.westhost.com/project48.htm
As loud as any other closed-box can go with a given Vd.
Regards
Charles
I have been looking into transmission lines and it appears that they also can extend the range significantly below Fs (seem like .5 to .75 8va). My 15" MI woofer with Fs of 45Hz sims an easy 30Hz Fc with 2.7m TL. Using one of the 15s like the titans with Fs around 20Hz should be nicely infrasonic. Just another possibility. EBS alignment is another reasonable possibility to get you down around 10Hz. I don't think a really huge woofer will be necessary.
mike
mike
A review of a 21" Bag End sub...
http://ultimateavmag.com/features/704way/index2.html
...which mentions that Todd-AO needed 22 Bag End subs while mixing the soundtrack for Black Hawk Down.
Not exactly the best boom for your buck. You can currently buy 20 Tempests for the list price of one of these subs (not including the processor). I'm just guessing, but I suspect that 20 Tempests in suitable boxes would be enough bass for most of us, and possibly all the neighbors on the block.
http://ultimateavmag.com/features/704way/index2.html
...which mentions that Todd-AO needed 22 Bag End subs while mixing the soundtrack for Black Hawk Down.
Not exactly the best boom for your buck. You can currently buy 20 Tempests for the list price of one of these subs (not including the processor). I'm just guessing, but I suspect that 20 Tempests in suitable boxes would be enough bass for most of us, and possibly all the neighbors on the block.
A different way
http://www.diyaudio.com/forums/showthread.php?s=&threadid=67028&highlight=
I got down to 10Hz in my 20' x 10' room with 3 tempests in sealed boxes, but never played any pipe organ so don't know if it has higher subsonics than dvd material. - Never bottomed them at reference or above fwiw.h
Rob.
http://www.diyaudio.com/forums/showthread.php?s=&threadid=67028&highlight=
I got down to 10Hz in my 20' x 10' room with 3 tempests in sealed boxes, but never played any pipe organ so don't know if it has higher subsonics than dvd material. - Never bottomed them at reference or above fwiw.h
Rob.
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