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[Austin Aske]

Wondering if anyone has any good sub suggestions. Currently we have been using the JBL SRX728's but are in need of more and sadly they are becoming very hard to find. Looking for a good value that is scalable down to 1 aside to 8 if or more if needed to be paired with our line array. One that has peaked our interest are the L Acoustic sb28's but are unsure on pricing so if you have any feedback on that it would be much appreciated.

Thanks,
Austin

[Doug Fowler]

Wondering if anyone has any good sub suggestions. Currently we have been using the JBL SRX728's but are in need of more and sadly they are becoming very hard to find. Looking for a good value that is scalable down to 1 aside to 8 if or more if needed to be paired with our line array. One that has peaked our interest are the L Acoustic sb28's but are unsure on pricing so if you have any feedback on that it would be much appreciated.

Thanks,
Austin

How many 728s do you have?

You will surely want to have all matching subs, and the 728s will sell for a premium if they are in good shape.  I'll bet you could unload them in the Marketplace in short order.

Check the VUE Audiotechnik AS-428.  Not too heavy, goes pretty low (mid 30s easily), nice punchy impact.  I haven't mixed on it but I did do about a hundred demos with a stack of 2.

It has interlocking skids, as you can see from the side angle.

I think you will pleased with the price point, if you were considering SB-28 ;-)  What is the ballpark street price of SB-28, power and DSP?

One often overlooked aspect of this box is it has 4 cones in it.  The power (hence heat) is spread across 4 voice coils rather than 2, so I _suspect_ for high duty cycle music (EDM) this has an advantage.

Power - a stack of 2 will take all that one channel of fp14000 can deliver before getting into voltage limiting.  That was a 4 ohm nominal load; the demo boxes were wired series-parallel for an 8 ohm nominal configuration.  I'm pretty sure you can get it wired as 4 ohms per box if you wish.

http://www.vueaudio.com/products/as-418/

[Doug Fowler]

Don't forget about BASSMAXX, also.

http://www.bassmaxx.com/pages/product_sub_SSP218.php

I also very much like BASSMAXX B-Zero, for tone.  It's a single 18 on a horn but it sounds fabulous IMO.

So, there are two often overlooked solutions (VUE and BASSMAXX).  I'm sure others will chime in with the "usual suspects" (QRX, EAW, etc).

Danley Sound Labs also offers great subs if you can afford them.

DAS Audio has some nice double 18s, I have tweaked on them two or three times, some version of AERO 218s.

http://www.dasaudio.com/en/cp/aero-series-2-en/page/2/

There are lots of good products out there, look beyond the obvious ;-)

edit to add DAS.....

[Kyle_Keating]

How many 728s do you have?

You will surely want to have all matching subs, and the 728s will sell for a premium if they are in good shape.  I'll bet you could unload them in the Marketplace in short order.

Check the VUE Audiotechnik AS-428.  Not too heavy, goes pretty low (mid 30s easily), nice punchy impact.  I haven't mixed on it but I did do about a hundred demos with a stack of 2.

It has interlocking skids, as you can see from the side angle.

I think you will pleased with the price point, if you were considering SB-28 ;-)  What is the ballpark street price of SB-28, power and DSP?

One often overlooked aspect of this box is it has 4 cones in it.  The power (hence heat) is spread across 4 voice coils rather than 2, so I _suspect_ for high duty cycle music (EDM) this has an advantage.

Power - a stack of 2 will take all that one channel of fp14000 can deliver before getting into voltage limiting.  That was a 4 ohm nominal load; the demo boxes were wired series-parallel for an 8 ohm nominal configuration.  I'm pretty sure you can get it wired as 4 ohms per box if you wish.

http://www.vueaudio.com/products/as-418/

That make -3dB in SPL per 1 watt compared to just using two drivers which negates the advantage of the extra voice coils.

[g'bye, Dick Rees]

That make -3dB in SPL per 1 watt compared to just using two drivers which negates the advantage of the extra voice coils.

The advantage to which he referred was that by spreading out the thermal waste energy over four drivers, they're likely to handle the proposed program load better.

Pushing the drivers into thermal compression will diminish the output of the boxes.  Keeping them there for longer periods of time will result in failure due to heat.

A 3dB loss due to whatever will not be nearly as noticeable as a complete failure.

[Art Welter]

Check the VUE Audiotechnik AS-428.  Not too heavy, goes pretty low (mid 30s easily), nice punchy impact.  I haven't mixed on it but I did do about a hundred demos with a stack of 2.

One often overlooked aspect of this box is it has 4 cones in it.  The power (hence heat) is spread across 4 voice coils rather than 2, so I _suspect_ for high duty cycle music (EDM) this has an advantage.

Doug,

Kyle Keating is correct, an isobaric arrangement offers no advantage from a heat standpoint, as the reference efficiency is half that of a single driver, twice the power is needed for the same SPL.
Each isobaric push-pull pair of the 12mm Xmax  drivers only displace the same amount of air as a single driver, but the compound pair's Vas is half, twice as "stiff" as one driver.

The only advantage this affords is the box size can be reduced by approximately 1/2 for the same low frequency extension as a single would have, or conversely, a lower Fb can be had in the same size box.

Classic Hoffman's law, loud, low or small, pick two.
In this case, loud and low, using double the amp and speaker cost.

Art

[Doug Fowler]

Doug,

Kyle Keating is correct, an isobaric arrangement offers no advantage from a heat standpoint, as the reference efficiency is half that of a single driver, twice the power is needed for the same SPL.
Each isobaric push-pull pair of the 12mm Xmax  drivers only displace the same amount of air as a single driver, but the compound pair's Vas is half, twice as "stiff" as one driver.

The only advantage this affords is the box size can be reduced by approximately 1/2 for the same low frequency extension as a single would have, or conversely, a lower Fb can be had in the same size box.

Classic Hoffman's law, loud, low or small, pick two.
In this case, loud and low, using double the amp and speaker cost.

Art

Good stuff, thanks for the clarification. 

[Kyle_Keating]

Thanks Art

The low Q is nice for small boxes, but a 3dB slide in SPL is hefty price indeed! Doesn't it look like to you that they pushed the front baffle back to fit the front drivers? Seems like they could just make the box bigger and use a standard driver set up.

[Art Welter]

Thanks Art

The low Q is nice for small boxes, but a 3dB slide in SPL is hefty price indeed! Doesn't it look like to you that they pushed the front baffle back to fit the front drivers? Seems like they could just make the box bigger and use a standard driver set up.

They could have, but four drivers using twice as much power sounds so powerful  !

The internal volume can be reduced by approximately 1/2 for an isobaric pair, but the clam shell arrangement of the cones robs internal space, so the net effect is only a bit lower Fb achievable at double the expense. Still, if a cabinet can go a little lower in the same size, it may be perceived as having an advantage.
If they used drivers as deep as the Aura (or whatever the deep neo magnet driver is in your avatar) the quad cabinet would hardly have any advantage over a dual of the same external size.

Funny, using just one of the drivers they use in a single tapped horn of the same cabinet size would net about the same output as all four (using 1/4 the power) in the isobaric clam shell bass reflex cabinet, with a F3 only about 5 Hz higher.

[Kenneth Berger]

Doug,

Kyle Keating is correct, an isobaric arrangement offers no advantage from a heat standpoint, as the reference efficiency is half that of a single driver, twice the power is needed for the same SPL.
Each isobaric push-pull pair of the 12mm Xmax  drivers only displace the same amount of air as a single driver, but the compound pair's Vas is half, twice as "stiff" as one driver.

The only advantage this affords is the box size can be reduced by approximately 1/2 for the same low frequency extension as a single would have, or conversely, a lower Fb can be had in the same size box.

Classic Hoffman's law, loud, low or small, pick two.
In this case, loud and low, using double the amp and speaker cost.

Art

This misses the point of this system, it is the same size or smaller than virtually all dual 18 inch subwoofers, offers lower distortion and less power compression AS COMPARED to dual driver systems. It is competitively prices to DUAL driver systems. It has the same efficiency as a dual driver system 2x the power handling and 1/2 the power compression for a given output as compared to DUAL driver systems.
Yes it is true when looked at as a quad driver system it would be 3 dB louder if it was not an isobaric design it would also have to be 3dB bigger.

One of our key design objectives is real output after power compression and in this the AS418 work, suggest you listen to it compared to similar sized dual driver system a we are confident you will be impressed.

And as for a horn loaded alternative it would have to be much larger to go anywhere near as low as a vented system, but you do get the efficiency.

Sorry if I am ranting but been traveling to long today!

[Art Welter]

This misses the point of this system, it is the same size or smaller than virtually all dual 18 inch subwoofers, offers lower distortion and less power compression AS COMPARED to dual driver systems.

Yes it is true when looked at as a quad driver system it would be 3 dB louder if it was not an isobaric design it would also have to be 3dB bigger.

And as for a horn loaded alternative it would have to be much larger to go anywhere near as low as a vented system, but you do get the efficiency.

Kenneth,

Since you don't post any frequency response curves, hard to compare sensitivity or efficiency of the AS-418 to anything else.
The  EAW SB-1000/1000Z/1000ZP have half space sensitivities from 99-102 with similar LF claims as the AS-418 in a slightly smaller cabinet, 15.64 cubic feet compared to the AS-418 at 16.54 cubic feet.

An SB-1000z was compared to the smaller Danley TH-118 tapped horn (14.41 cubic feet):

http://soundforums.net/varsity/6793-th118vssb1000z.html

The slightly smaller single driver tapped horn had slightly more upper output, the SB-1000 slightly more extended LF.
The B&C 18SW115-4 used in the DSL TH-118 has more Xmax than the drivers used in the AS-418 (look like a shorter winding version of the B&C18TBX100), my money would be on the TH-118 having higher ultimate output.

As far as the reduction of even order distortion (leaving the odd sounding odd order distortion) the push pull isobaric arrangement provides, that would be something to consider, though it seems few care about even order distortion, as it makes a sub "sound louder".

Art

[Kyle_Keating]

This misses the point of this system, it is the same size or smaller than virtually all dual 18 inch subwoofers, offers lower distortion and less power compression AS COMPARED to dual driver systems. It is competitively prices to DUAL driver systems. It has the same efficiency as a dual driver system 2x the power handling and 1/2 the power compression for a given output as compared to DUAL driver systems.
Yes it is true when looked at as a quad driver system it would be 3 dB louder if it was not an isobaric design it would also have to be 3dB bigger.

One of our key design objectives is real output after power compression and in this the AS418 work, suggest you listen to it compared to similar sized dual driver system a we are confident you will be impressed.

And as for a horn loaded alternative it would have to be much larger to go anywhere near as low as a vented system, but you do get the efficiency.

Sorry if I am ranting but been traveling to long today!

I'll have to try and make a point to hear one of these subs one day. I honestly can't speak too much on this because I have never measured one or heard one.

[ProSoundWeb Community]