Am I wrong?

[Bob257]

I'm being told by a retailer that I have the wrong sub for my system. My system consists of a pair of Focal Elektra 1028be tower speakers driven by a Luxman 507uxii integrated amp. To that I added a REL T7/i sub. He told me that my speakers go down to 34 db so that sub is doing nothing for me. He said the minimum I need is the s/812 REL. My listening is all close field as I sit 6 feet from my speakers. Should I really spend $3000 on this other sub?

 

[shadyJ]

Your dealer is kind of wrong. That goofy little Rel sub won't get you that much deeper extension compared to your speakers, but it could help to smooth out the low-frequency response of your room. The problem is that your integrated amp has absolutely no EQ abilities to help that, and it doesn't even have rudimentary bass management as far as I can see. It simply isn't built for adding subwoofers.

To be honest, I wouldn't add a subwoofer without some kind of bass management. Otherwise, all you will be doing is boosting bass levels. If all you want is louder bass, sure, add a sub, but you won't have much of a way to integrate it properly.

For a system like yours, I would be looking at this analog Hsu high-end crossover to integrate bass management into your system. Then add a sub that doesn't use DSP in the signal path. Hsu and Rythmik use analog amps. I think the Outlaw Audio Ultra-X12 also uses an analog amp. The reason you should be looking at analog amps is DSPs add latency that you have no way of compensating for in your system. Rel uses analog amps, but they have pretty sad performance for the money, their decent subs cost a fortune. I think Starke Sound uses Analog amplifiers but I am not certain.

 

[Pogre]

For a system like yours, I would be looking at this analog Hsu high-end crossover to integrate bass management into your system.

I did not know HSU sold such a thing. Huh. Interesting.

 

[AcuDefTechGuy]

Or like-new dbx DriveRack PA2 from Amazon Warehouse for Crossover and 8-band Parametric EQ.

Amazon.com: dbx DriveRack PA 2, USB, Black, 3.80 x 11.00 x 22.00 inches PA2 : Musical Instruments

Buy dbx DriveRack PA 2, USB, Black, 3.80 x 11.00 x 22.00 inches PA2: Musical Instruments - Amazon.com ✓ FREE DELIVERY possible on eligible purchases

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dbx DriveRack PA2

control app for all 4 major OSes All you need to get the most from your PA. Now with ...

dbxpro.com

 

[shadyJ]

Or like-new dbx DriveRack PA2 from Amazon Warehouse for Crossover and Parametric EQ.

Amazon.com: dbx DriveRack PA 2, USB, Black, 3.80 x 11.00 x 22.00 inches PA2 : Musical Instruments

Buy dbx DriveRack PA 2, USB, Black, 3.80 x 11.00 x 22.00 inches PA2: Musical Instruments - Amazon.com ✓ FREE DELIVERY possible on eligible purchases

www.amazon.com

I don't think that would be a great solution. That is meant for PA system, and live sound processors and amps tend to have a high noise floor and distortion level. The noise floor could be a problem for a guy like the OP who sits 6 feet from tower speakers.

 

[AcuDefTechGuy]

I don't think that would be a great solution. That is meant for PA system, and live sound processors and amps tend to have a high noise floor and distortion level. The noise floor could be a problem for a guy like the OP who sits 6 feet from tower speakers.

dbx specs:

THD+N 0.003%. Looks pretty good to me. Let’s see how the HSU compares? Are there even any specs in the HSU? For all me know, THD+N could be 0.1%.

As for “PA” or “Pro” crowd, the Crown and QSC amps are made for “Pro” and probably “PA” too. But they sound good.

 

[shadyJ]

dbx specs:

THD+N 0.003%. Looks pretty good to me. Let’s see how the HSU compares?

As far as “PA” or “Pro” crowd, the Crown and QSC amps are made for “Pro” and probably “PA” too. But they sound good.

The DriveRack VENU360, also from dbx pro, also has similar specification, but look how it actually measured. I think the numbers from the spec sheet are just of the DAC and ADC chips themselves, and not of the unit as a whole. There are no ADCs or DACs in the Hsu unit, so I think it does stand a higher chance of offering better performance. Much less complicated circuitry.

 

[mtrot]

Eh, I bet that T7-i will play down around 30 Hz with a lot more power than the 1028Be, which probably start to roll off a lot higher than 34Hz. Sure, you don't currently have bass management, but you could set the sub's crossover and volume so that it just provides a bit more bass foundation. I guess it comes down to how sophisticated you want to make your system and how much much you are willing to spend.

 

[AcuDefTechGuy]

The DriveRack VENU360, also from dbx pro, also has similar specification, but look how it actually measured. I think the numbers from the spec sheet are just of the DAC and ADC chips themselves, and not of the unit as a whole. There are no ADCs or DACs in the Hsu unit, so I think it does stand a higher chance of offering better performance. Much less complicated circuitry.

THD+N of 0.006% at 4Vrms and SINAD of 84dB?

I mean it's not the best in the world, but not audible either.

And unless Amir or somebody measures the HSU, I wouldn't assume anything.

 

[BoredSysAdmin]

I'm being told by a retailer that I have the wrong sub for my system. My system consists of a pair of Focal Elektra 1028be tower speakers driven by a Luxman 507uxii integrated amp. To that I added a REL T7/i sub. He told me that my speakers go down to 34 db so that sub is doing nothing for me. He said the minimum I need is the s/812 REL. My listening is all close field as I sit 6 feet from my speakers. Should I really spend $3000 on this other sub?

One more point according to these 3rd party measurements your speakers aren't REALLY going down to 34HZ. The more realistic number (at -3db) is 48hz - so you do need a sub to fill the lowest bass.
James is also correct that your current sub T7i doesn't do all that much. It SHOULD produce 30hz at -6dB in-room, which isn't much, realistically it produces less than that.
My suggestion is to skip the analog crossover, sell your REL sub and get a sub with a built-in DSP and crossover, like the SVS PB-2000 Pro or higher - depends on your room size and not how far from speakers you sit from.
You'd wire pre-out from your Luxman to SVS sub and then back to your Luxman.

I'd also throw a stone at @AcuDefTechGuy, the SVS's sub DSP part is both more capable and easier to use than the pro-audio gear he recommended.

 

[Mikado463]

I employ a Velodyne DD15 in my kit and IMO it does a superb job of bass management and integration with respect to my L/R speakers and room.

 

[lovinthehd]

I employ a Velodyne DD15 in my kit and IMO it does a superb job of bass management and integration with respect to my L/R speakers and room.

It has an actual crossover for the speakers?

 

[Mikado463]

It has an actual crossover for the speakers?

for the L/R speakers, no. Just excellent room eq with its Digital Drive system......

https://velodyneacoustics.com/pdf/digitaldrive/DDManual.pdf

 

[lovinthehd]

for the L/R speakers, no. Just excellent room eq with its Digital Drive system......

https://velodyneacoustics.com/pdf/digitaldrive/DDManual.pdf

Then it is not providing bass management for your speakers.....then again few subs provide such either.

@Bob257 I sure as heck wouldn't buy Rel subs myself, much better options for the money (as well as aesthetics). I'd avoid a salesman suggesting such myself.

The Hsu option may be nice, or you can go a more modern solution, which includes management of delay, from someone like miniDSP.com; at least your Luxman has pre-outs and a main-in for insertion of an external bass management unit.

 

[Mikado463]

Then it is not providing bass management for your speakers.....then again few subs provide such either.

gotcha, understood, I guess I should have 'bass re-enforcement' for the overall set up.