Adding a sub to a 2ch system

[TLS Guy]

The minidsp SHD has high enough output for the AHB2 so he doesn't need to replace it with a Hypex amp unless he wants to.

By far his best solution is to run his system as he does now, and just connect the sub and set the crossover to F3 + 50% for a start. That works really well, and should be used far more often then it is. He has a capable amp, and so we don't need to worry about that, and his speakers will work no harder than they do now.

Full bass management adds unnecessary phase shifts, and if you speakers are ported you will have a much more seamless crossover, by this method. I know I am right about this.

 

[PENG]

By far his best solution is to run his system as he does now, and just connect the sub and set the crossover to F3 + 50% for a start. That works really well, and should be used far more often then it is. He has a capable amp, and so we don't need to worry about that, and his speakers will work no harder than they do now.

Full bass management adds unnecessary phase shifts, and if you speakers are ported you will have a much more seamless crossover, by this method. I know I am right about this.

According to the OP:

Trying to help my friend who despite having a good 2ch system is not happy with the bass. He would like to add a small sub (his room is quite small).

So yes, I agree with you he should try what you are suggesting first, and if that cannot satisfy him then there is a plan B, such as the minidsp SHD, that can do more bass management, and/or ultimately, use Dirac Live.

 

[PENG]

Is it confirmed yet that Benchmark will be the preamp, I just couldn't go back and read after what I last remembered?

Edit: I see the MiniSHD is in the chain.

According to the first post, his friend already has a Benchmark preamp, that, like the AHB2 power amp, the preamp has ultra low noise and distortions, but he doesn't like the bass he's getting.

His system - PC with JRiver, some external DAC, Benchmark preamp, Benchmark amp, KEF R3. I told him this pair of Benchmark amps is overkill for what he wants, good AVR would be enough, but... Anyway, what is the best way to connect a sub? Preamp does not have preouts. Also, how to get crossovers, delays and volumes sorted?

Problem is, any preamp or preamp/processor that has good bass management and/or RC system, will not have the super low noise and distortions specs that the Benchmark preamp/power amp offers, though the minidsp SHD can come close, close enough...

As TLSGuy suggested, simply adding a sub and play with the crossover may do the trick, but depending on his room and the placement options for the KEF R3, it may not be good enough if the R3 does not play well with the sub/placement.

miniDSP SHD - Roon Ready Preamplifier with Dirac Live® room correction
Minidsp SHD Review Updated (DSP, DAC & Streamer) | Audio Science Review (ASR) Forum

 

[TLS Guy]

According to the first post, his friend already has a Benchmark preamp, that, like the AHB2 power amp, the preamp has ultra low noise and distortions, but he doesn't like the bass he's getting.



Problem is, any preamp or preamp/processor that has good bass management and/or RC system, will not have the super low noise and distortions specs that the Benchmark preamp/power amp offers, though the minidsp SHD can come close, close enough...

As TLSGuy suggested, simply adding a sub and play with the crossover may do the trick, but depending on his room and the placement options for the KEF R3, it may not be good enough if the R3 does not play well with the sub/placement.

miniDSP SHD - Roon Ready Preamplifier with Dirac Live® room correction
Minidsp SHD Review Updated (DSP, DAC & Streamer) | Audio Science Review (ASR) Forum

Those speakers seem really nice, and measure well apart from being bass shy.

As far as I can tell from the measurements F3 is 50 to 60 Hz range, so running the subs to come in in the 80 to 100 Hz range should work very well indeed. I think that cold be judged by ear. I would expect the rig to sound very good. Doubt minidsp or Dirac would improve the situation.

 

[Andrein]

Is it confirmed yet that Benchmark will be the preamp, I just couldn't go back and read after what I last remembered?

Edit: I see the MiniSHD is in the chain.

Yes, my friend already has Benchmark amp and pre amp. He is going to buy Benchmark DAC too))) He is beyond the period when he can return them. And looks like he does not want to

 

[Andrein]

My friend returned from holiday this week. He tried to connect some old sub (Q accoustics) and though the sub is not great but it added a bit of bass. He might buy svs sb3000 micro instead. Also, his R3 are very close to the wall. So we closed its ports and the sound now is better/cleaner in the bass region. So it looks like he might be fine without bass management. He will play with diff crossover f3s. And buy a better sub as this Q Accoustics is a weakest point in his system now. Once I finish playing with my system and Yamaha A1070 PEQ (separate thread I created still has 0 replies btw), we'll measure his system again and check if those dips of around 25db went away with R3 ports closed

 

[everettT]

My friend returned from holiday this week. He tried to connect some old sub (Q accoustics) and though the sub is not great but it added a bit of bass. He might buy svs sb3000 micro instead. Also, his R3 are very close to the wall. So we closed its ports and the sound now is better/cleaner in the bass region. So it looks like he might be fine without bass management. He will play with diff crossover f3s. And buy a better sub as this Q Accoustics is a weakest point in his system now. Once I finish playing with my system and Yamaha A1070 PEQ (separate thread I created still has 0 replies btw), we'll measure his system again and check if those dips of around 25db went away with R3 ports closed

I like the idea of plugging them then no high pass filter is really necessary. I'd also look at a slightly better subwoofer unless space is at a super premium. The dual 10" from Sieberg Audio would be an excellent fit for low distortion. Their max burst numbers still behave very well.

Sigberg Audio 10D Subwoofer Review: Best Performing Small Sub?

Our review of the Sigberg Audio 10D subwoofer shows what happens when a designer puts some of the world’s best audio components into a small package that hits above its size class. Pricey but potent.

www.audioholics.com

 

[TLS Guy]

I like the idea of plugging them then no high pass filter is really necessary. I'd also look at a slightly better subwoofer unless space is at a super premium. The dual 10" from Sieberg Audio would be an excellent fit for low distortion. Their max burst numbers still behave very well.

Sigberg Audio 10D Subwoofer Review: Best Performing Small Sub?

Our review of the Sigberg Audio 10D subwoofer shows what happens when a designer puts some of the world’s best audio components into a small package that hits above its size class. Pricey but potent.

www.audioholics.com

I agree, that sub would be of a quality commensurate with the rest of his system. I agree that he should not be trading way down to an AV receiver.

That Sigberg sub would really complete his system.

 

[JLGF1]

So, any SVS or similar subs with high pass speaker level or line level output kind of solutions are not likely going to be acceptable to him.

He doesn't have a lot of ultra-low-noise options based on the HW he has to work with and what he can introduce in the chain. The miniDSP is no stellar champion in the specs department either. Some compromises will need to be made.

The SVS sub mentioned was not a recommendation for that sub per se. It was an example to show that, yes, there are subs out there with HPF (one poster in this thread implied they were super rare).

You can't always get what you want.

 

[JLGF1]

You could place an EQ in the mains signal path to HPF them. That's an option I would consider (Audio Control), but I'm not super anal about mostly inaudible distortion at miniscule levels. I have a secondary small office system placed on built in bookshelves using an NAD 3045 because of 12 inch depth constraints and that's exactly what I do. I place another EQ in the sub chain. Overall, it sounds great. Without the HPF you can visually tell that the 6 inch main woofers are working too hard. But, I guess that would be mitigated to some degree with the 3-way R3 versus my 2-ways.

YMMV.

 

[TLS Guy]

You could place an EQ in the mains signal path to HPF them. That's an option I would consider (Audio Control), but I'm not super anal about mostly inaudible distortion at miniscule levels. I have a secondary small office system placed on built in bookshelves using an NAD 3045 because of 12 inch depth constraints and that's exactly what I do. I place another EQ in the sub chain. Overall, it sounds great. Without the HPF you can visually tell that the 6 inch main woofers are working too hard. But, I guess that would mitigated to some degree with the 3-way R3 versus my 2-ways.

YMMV.

It has to do with the design of the bass driver rather then whether it is two or three way. For instance small drivers based on the earlier Dynaudio designs from Morel and Skaaning Audio Technology can handle enormous amounts of power even in the low bass, without distress.
Those drivers can be produced by those firms due to a long complex commercial and legal history.

I am very partial to those designs. Unfortunately Dynaudio now has Chinese masters, but in any event exited the DIY market years ago as far as making their drivers available.

 

[PENG]

He doesn't have a lot of ultra-low-noise options based on the HW he has to work with and what he can introduce in the chain. The miniDSP is no stellar champion in the specs department either. Some compromises will need to be made.

The SVS sub mentioned was not a recommendation for that sub per se. It was an example to show that, yes, there are subs out there with HPF (one poster in this thread implied they were super rare).

You can't always get what you want.

You are repeating something similar to what I said in post#51 so I am in agreement. Trouble is, when a thread starting to get long, people forget what other posters have said prior and the thread could start to get messy, such as repeating stuff, argument for nothing etc...

I am not a minidsp fan, and I think their lower end ones such as the 2X4HD (that I do own one) are way overrated/overused, but facts are facts, they do have the SHD model that has been suggested as a viable option for the OP (his friend) and it is the one that actually has very low if now ultra low noise.

Even Amir commented on the low noise level is not remotely an audible conc
"We see faint signs of the original problem but they are now very nicely attenuated and at -130 dB and lower, not remotely an audible concern."

It would be nice if there is something that has similar flexible bass management option to have noise level 10 dB below the AHB2, but again we both know that is probably not available on the market at the moment.

There may be another option but the OP/his friend would have to make some enquiries. The solution I am thinking is to use the sub with HPF option that has been suggested, but request an "ultra low" noise active HPF from the manufacturer. I think Rythmik will likely be willing to do it, on request, for a price of course. When I bought mine with the option, they used a good OPA (don't remember the number) that is not SOTA but I am sure if I requested that they use something better such as the NE5532 (or better), they would have done it for me. SVS may do that too, but again it would have been a special request.

Still, the minidsp SHD solution offers more flexibility, at a much higher cost than the simple HPF built in to a subwoofer. That is not likely going to be a problem for the OP's friend if he is fixated on "ultra-low" noise even if it not practically necessary. I may go that route myself, unless someone knows of a better option than the minidsp SHD. That's because I am one of those (if that's ocd.., so be it) who wants to have the best specs/measurements on paper.

 

[PENG]

My friend returned from holiday this week. He tried to connect some old sub (Q accoustics) and though the sub is not great but it added a bit of bass. He might buy svs sb3000 micro instead. Also, his R3 are very close to the wall. So we closed its ports and the sound now is better/cleaner in the bass region. So it looks like he might be fine without bass management. He will play with diff crossover f3s. And buy a better sub as this Q Accoustics is a weakest point in his system now. Once I finish playing with my system and Yamaha A1070 PEQ (separate thread I created still has 0 replies btw), we'll measure his system again and check if those dips of around 25db went away with R3 ports closed

I have a very similar 2 channel application so I have been researching for a solution for month. So far, the only one that comes close in terms of budget constraint, practicality and tweakability, is the minidsp SHD. (post#92), but I am waiting for others on this thread, to suggest even more affordable but comparable in terms of theoretical performance options.

Actually performance in terms of FR is very nice using the 2X4 HD so for sure the SHD will work, but I know the 2X4HD's SINAD is lower than that of my DACs and power amps so I don't really like this solution, but even on the practical side, the minidsp 2XHD's 2 V output is just too low, the SHD's 4 V is much better, obviously.

 

[Andrein]

I have a very similar 2 channel application so I have been researching for a solution for month. So far, the only one that comes close in terms of budget constraint, practicality and tweakability, is the minidsp SHD. (post#92), but I am waiting for others on this thread, to suggest even more affordable but comparable in terms of theoretical performance options.

Actually performance in terms of FR is very nice using the 2X4 HD so for sure the SHD will work, but I know the 2X4HD's SINAD is lower than that of my DACs and power amps so I don't really like this solution, but even on the practical side, the minidsp 2XHD's 2 V output is just too low, the SHD's 4 V is much better, obviously.

View attachment 61572

Spoke to my friend. He wants to try sub with lpf only and natural R3 roll off to see how this measures with various cross over f3s before looking at SHD. He is indeed a bit fixated on ultra low distortion. He is waiting for new Benchmark DAC4 which will allegedly have Sinad 2db better than DAC3)))

 

[Andrein]

I like the idea of plugging them then no high pass filter is really necessary. I'd also look at a slightly better subwoofer unless space is at a super premium. The dual 10" from Sieberg Audio would be an excellent fit for low distortion. Their max burst numbers still behave very well.

Sigberg Audio 10D Subwoofer Review: Best Performing Small Sub?

Our review of the Sigberg Audio 10D subwoofer shows what happens when a designer puts some of the world’s best audio components into a small package that hits above its size class. Pricey but potent.

www.audioholics.com

The sub should be small and I don't think 2 subs are an option due to space concerns. When he saw my 2 sb2000 he said those are too large for his room. That is why I looked at sb3000 mini which is significantly smaller and can still go low enough for music (only music).

 

[everettT]

The sub should be small and I don't think 2 subs are an option due to space concerns. When he saw my 2 sb2000 he said those are too large for his room. That is why I looked at sb3000 mini which is significantly smaller and can still go low enough for music (only music).

I understand, it's a dual 10 opposed so both are in the same sealed box and is around the same size as your SB, which I consider small, FWIW. I'd still push him as he will be much more satisfied overall then with a compromise for a few inches. Hope he appreciates all your help, as sounds like he will have a nice little system.

 

[PENG]

Spoke to my friend. He wants to try sub with lpf only and natural R3 roll off to see how this measures with various cross over f3s before looking at SHD. He is indeed a bit fixated on ultra low distortion. He is waiting for new Benchmark DAC4 which will allegedly have Sinad 2db better than DAC3)))

That's what TLSG and I have suggested, as long as he uses the LPF only so the sub only gets the LF, and the R3 will be getting unfiltered/full range signal. If he uses the HPF to feed the R3, then while the R3 will likely integrate better with the sub, SINAD will suffer, though it will not likely be an audible concern.

 

[JLGF1]

If he uses the HPF to feed the R3, then while the R3 will likely integrate better with the sub, SINAD will suffer, though it will not likely be an audible concern.

I think we might agree here (?) that the disadvantage of bad sub integration could be orders of magnitude more adverse (ie very audible) impact to SQ compared to any (mostly inaudible) distortion specs. Like a flea on an elephant, imo. I just re-tuned my office with a new sub and I can guarantee that the lack of sub EQ on the overall SQ would have completely dwarfed the distortion anywhere else in the chain. Not even close; it would have sounded horrible without that tuning in the sub region, as is very common.

Yes, I missed your miniDSP (S)HD post which at $1300 is way more than I expected (and $400 more than the SVS 3000-micro SW the OP might consider). So, I wasn't considering those solutions that cost more than the SW itself which doesn't make any sense to me, but to each his own. And though the room has been referred to as "small" I'm beginning to get the idea that it might be a closet.

 

[JLGF1]

and is around the same size as your SB[2000]

The 3000-micro is sized around an 11 inch cube. So, it shaves another 3.5 inches off the already modest size of the SB2000. That's why I think the listening room must be a walk-in closet.

 

[lovinthehd]

Just a few notes on the SVS Micro 3000 sub. It is dual 8", not 10" and it does not appear to offer a high pass filter.