Adding a sub to a 2ch system

[PENG]

I thought about minidsp too. They still have those analog 2x4hd units

I was about to sell my 2X4HD for $100 but changed my mind in the last minute because the buyer is in the US. So now I make use of it as an active crossover with my 2 channel system and a $79 Nobsound monolock amp.

The problem is, if you friend knows the minidsp will negate the super low THD+N totally, he would start second guessing whether the combo will sound better or worse so better not tell him anything about the minidsp's specs.

I should have kept my Denon AVR-X4400H for that job, you can't beat a good AVR for such 2 channel systems.

 

[Andrein]

I was about to sell my 2X4HD for $100 but changed my mind in the last minute because the buyer is in the US. So now I make use of it as an active crossover with my 2 channel system and a $79 Nobsound monolock amp.

The problem is, if you friend knows the minidsp will negate the super low THD+N totally, he would start second guessing whether the combo will sound better or worse so better not tell him anything about the minidsp's specs.

I should have kept my Denon AVR-X4400H for that job, you can't beat a good AVR for such 2 channel systems.

Yeah, these multiple digital to analog and vise versa conversions will kind of invalidate the uniqueness of Benchmark amps. I know that. @PENG , what solution would you choose in this situation if you wanted to keep the amps but not loose much of sound quality and low distortion (though probably inaudible)?

 

[PENG]

Yeah, these multiple digital to analog and vise versa conversions will kind of invalidate the uniqueness of Benchmark amps. I know that. @PENG , what solution would you choose in this situation if you wanted to keep the amps but not loose much of sound quality and low distortion (though probably inaudible)?

I am in search of such a solution myself since I mistakenly traded in both my Marantz AV8801 and the Denon X4400H. The cheap Nobsound amp (it comes with crossover feature) is a stop gap measure.

A used AVR-X3600H can work, if you can find one. I am glad you say "not loose much", without the word "much", there is simply nothing you can do because there are simply no 2.1 preamp, preamp dac, or anything, that comes with bass management yet has SINAD equal to that of the AHB1. A used AVR-X3700H will obviously work too.

AVRs can be that good, but people just don't trust science enough, and yet they trust marketing hype and forum hearsay because we humans typically believe in what they want to believe or what they heard via hearsay previously.

DENON AVR-X3700H 9.2-Ch x 105 Watts 8K A/V Receiver w/HEOS | Accessories4less

A very decent, but expensive solution is the minidsp SHD:

miniDSP SHD - Roon Ready Preamplifier with Dirac Live® room correction

The 2X4HD really won't work well with the AHB2 even if he doesn't know the poor SINAD spec (not likely audible but as mentioned...), because it's maximum output is 2 V, a little low for the AHB2's low gain.

 

[Andrein]

I am in search of such a solution myself since I mistakenly traded in both my Marantz AV8801 and the Denon X4400H. The cheap Nobsound amp (it comes with crossover feature) is a stop gap measure.

A used AVR-X3600H can work, if you can find one. I am glad you say "not loose much", without the word "much", there is simply nothing you can do because there are simply no 2.1 preamp, preamp dac, or anything, that comes with bass management yet has SINAD equal to that of the AHB1. A used AVR-X3700H will obviously work too.

AVRs can be that good, but people just don't trust science enough, and yet they trust marketing hype and forum hearsay because we humans typically believe in what they want to believe or what they heard via hearsay previously.

DENON AVR-X3700H 9.2-Ch x 105 Watts 8K A/V Receiver w/HEOS | Accessories4less

Yeah, avr can be very good. Just some people almost get heart attack when I say "avr"))) What if something like minidsp NanoAvr used? Connected via HDMI between PC and DAC? This should not affect sound quality as the signal is changed while being still digital? Or am I missing something?

https://www.minidsp.com/images/documents/Product%20Brief-nanoAVR.pdf

Yes max sample rate will go down to 96khz. But it is still 24bit which should be able to provide SNR of about 140db from what I read somewhere.

I might be wrong...

 

[Kingnoob]

Yeah, avr can be very good. Just some people almost get heart attack when I say "avr"))) What if something like minidsp NanoAvr used? Connected via HDMI between PC and DAC? This should not affect sound quality as the signal is changed while being still digital? Or am I missing something?

https://www.minidsp.com/images/documents/Product%20Brief-nanoAVR.pdf

Yes max sample rate will go down to 96khz. But it is still 24bit which should be able to provide SNR of about 140db from what I read somewhere.

I might be wrong...

This is why people who buy separates should ask on these forums before hand , if you want a sub don’t buy a pre amp or intigrated amp without sub outputs /inputs.
I doubt he’d lost any sound quality with an avr or avr like preamp.
Does svs and popular brands all have high level inputs ?

 

[Andrein]

This is why people who buy separates should ask on these forums before hand , if you want a sub don’t buy a pre amp or intigrated amp without sub outputs /inputs.
I doubt he’d lost any sound quality with an avr or avr like preamp.
Does svs and popular brands all have high level inputs ?

No, he wouldn't lost a lot with avr. I think he would get more tbh. High level inputs are like hacks these days. Svs don't even have them but there are other subs. The problem is how to have crossover done properly on both sub and speakers side.

 

[lovinthehd]

No, he wouldn't lost a lot with avr. I think he would get more tbh. High level inputs are like hacks these days. Svs don't even have them but there are other subs. The problem is how to have crossover done properly on both sub and speakers side.

Still, getting someone to give up nice 2ch gear can be hard especially with what they've likely "heard" about avrs. He doesn't need high level inputs with the mono pre-out, tho. The SVS SB/PB 1000 Pro models both have high level inputs still, tho seems to be gone from the models above that from a brief glance (not sure I'd call the Micro a step up, tho).

 

[JLGF1]

He doesn't need high level inputs with the mono pre-out, tho.

Except there will be no HPF for the mains; full range, which is not ideal. That's the point of using hi-level inputs via the sub (if available). Most sub makers have dropped hi-level inputs as they expect you to have bass mgmt, but you can still find some. eg REL

 

[Andrein]

Except there will be no HPF for the mains; full range, which is not ideal. That's the point of using hi-level inputs via the sub (if available). Most sub makers have dropped hi-level inputs as they expect you to have bass mgmt, but you can still find some. eg REL

How would hpf work for speakers? Speakers still connected to the amp and get full range? Or would speakers be connected to sub, i.e. sub in between applying lpf to itself and hpf to speakers? Do REL support this?

 

[MrBoat]

In a small room, it may not be necessary to HP the mains at all for 2 channel, but instead just LP the sub with regard to the mains. I have a couple systems that this works for, because all the mains were really missing was that very bottom. I essentially run my big system like this as well with the sub tuned about 1.25 times the mains F3 for the slightest overlap, which has the subs starting to come on around 45hz. At least if the mains are capable for most of a full range performance otherwise for music.

I've tried it with/without crossovers, speakers set to small and large. For the music I listen to, it doesn't need much in the way of finessing in the bass. Everything else can be solved via EQ.

 

[PENG]

Yeah, avr can be very good. Just some people almost get heart attack when I say "avr"))) What if something like minidsp NanoAvr used? Connected via HDMI between PC and DAC? This should not affect sound quality as the signal is changed while being still digital? Or am I missing something?

https://www.minidsp.com/images/documents/Product%20Brief-nanoAVR.pdf

Yes max sample rate will go down to 96khz. But it is still 24bit which should be able to provide SNR of about 140db from what I read somewhere.

I might be wrong...

There is no way you can get 140 dB SNR, even the best available preamp, preamp/processor can hit SNR that high. The spec says 103 dB DR so that's the best it can do under the most favorable conditions. Regardless, like the 2X4HD, it's output seems to max out at 2 V, so not quite suitable for the AHB2.

The only minidsp that I would use with the AHB2 is the SHD model that cost $1,300.

 

[Andrein]

There is no way you can get 140 dB SNR, even the best available preamp, preamp/processor can hit SNR that high. The spec says 103 dB DR so that's the best it can do under the most favorable conditions. Regardless, like the 2X4HD, it's output seems to max out at 2 V, so not quite suitable for the AHB2.

The only minidsp that I would use with the AHB2 is the SHD model that cost $1,300.

Ok. 140db is what 24bit format can give in theory. Didn't mean in practice for any particular model. That SHD is a good value. Was looking at it too. It can replace both DAC and preamp and gives sub preout and room correction with bass management too. But this might be not good enough for someone who wants to own separates)) Characteristics similar to Benchmark but 3 times cheaper or 5 if you count DAC. Though probably everything above 100db is indistinguishable anyway

 

[Andrein]

In a small room, it may not be necessary to HP the mains at all for 2 channel, but instead just LP the sub with regard to the mains. I have a couple systems that this works for, because all the mains were really missing was that very bottom. I essentially run my big system like this as well with the sub tuned about 1.25 times the mains F3 for the slightest overlap, which has the subs starting to come on around 45hz. At least if the mains are capable for most of a full range performance otherwise for music.

I've tried it with/without crossovers, speakers set to small and large. For the music I listen to, it doesn't need much in the way of finessing in the bass. Everything else can be solved via EQ.

We'll try just sub with just lpf. If he doesn't like it maybe he'll consider Minidsp SHD option. His R3 shows a huge dip of at least 25db at around 180hz on a chart in his room which to me is much bigger problem

 

[Kingnoob]

We'll try just sub with just lpf. If he doesn't like it maybe he'll consider Minidsp SHD option. His R3 shows a huge dip of at least 25db at around 180hz on a chart in his room which to me is much bigger problem

I can’t understand why preamp, intigrated etc even stereo receivers often don’t have subwoofer capability.
my bookshelf’s are on tv trays as surrounds actually take up more space then my towers lol if he had just gotten towers instead of bookshelves he might have had enough bass for music uses only . Although subs are a must for some music and movies .
Now you gotta hunt down a fix to an issue the manufacturers of these devices could solve easily .
I’ve got 2 receivers with no sub outputs but only use one of them , insignia one hooked to the micro sub I posted above .
Good luck ..

 

[lovinthehd]

Except there will be no HPF for the mains; full range, which is not ideal. That's the point of using hi-level inputs via the sub (if available). Most sub makers have dropped hi-level inputs as they expect you to have bass mgmt, but you can still find some. eg REL

High level inputs are more for those who don't have a sub pre-out. Most do not provide a high pass filter for the speakers, and as far as I've seen the Rels don't have that feature (i.e. the hpf, they make a big fuss about their high level input, tho).

 

[JLGF1]

High level inputs are more for those who don't have a sub pre-out.

Of course if you have a sub-out that is the preferred method. The problem here is no bass mgmt I presume (eg xover) so the mains will still be playing full range unless a HPF is used. It may be workable even if not ideal. Better would be a HPF in the main pre-outs, but it sounds like that's not available

There are some subs that have HPF but I don't have a definitive list.

 

[lovinthehd]

Of course if you have a sub-out that is the preferred method. The problem here is no bass mgmt I presume (eg xover) so the mains will still be playing full range unless a HPF is used. It may be workable even if not ideal. Better would be a HPF in the main pre-outs, but it sounds like that's not available

There are some subs that have HPF but I don't have a definitive list.

I've seen just a handful of subs with an actual crossover, and usually just on the low/line level connections, and often just a fixed value, too. This whole thread is because the OP's friend has a 2ch pre-amp without bass management (but does have a mono pre-out) and he wants to have his friend hi pass the speakers and what options there are to add it....or skip it.

 

[JLGF1]

does have a mono pre-out) and he wants to have his friend hi pass the speakers and what options there are to add it....or skip it.

Assuming the preamp has no HPF on the main outs, what other options would he have?

- xover in the sub
or
- external xover such as miniDSP
or
live with full-range signal to mains

Not a lot of good options, imo.

 

[Andrein]

Assuming the preamp has no HPF on the main outs, what other options would he have?

- xover in the sub
or
- external xover such as miniDSP
or
live with full-range signal to mains

Not a lot of good options, imo.

Yes, once my friend is back from holiday, we'll look at all these options. It will also depend if he can and want to replace his Benchmarks with something else, e.g. Minidsp SHD + Hypex NC502. Even if he is concerned about very low distortion this combination would work very well. And is cheaper. But that would not be all separates route. Let's see. There are not many options, but we can try at least. I think he tried to run some sub with speakers running full range and did not like results. But then I need to check how he actually connected that sub.

 

[sterling shoote]

Hi,

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).

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?

Buy a 2.1 preamp, the Parasound Halo P6 is excellent. This permits control of a passive subwoofer amped by any notion deemed appropriate. The PC will connect to preamp via usb for Saber DAC pleasure.