Sub question?

[Jamesw72]

Hi all,

Quick question..

Would it be better to connect my Sub (SF Gravis I) to my Wiim Ultra or my NAD C368?

Just thinking about this whilst conducting RC ..

 

[audiobliss]

I think it's better to run the sub and main speakers from the same source, so both from the amp or preamp. The sub will blend better with the main speakers.

 

[harkpabst]

I think it's better to run the sub and main speakers from the same source, so both from the amp or preamp. The sub will blend better with the main speakers.

Running passive speakers directly from a pre-amp? Doesn't sound like a good idea to me. I disagree in general, though.

Would it be better to connect my Sub (SF Gravis I) to my Wiim Ultra or my NAD C368?

Connecting the sub to the WiiM Ultra will enable you to high pass filter the signal to the C368 (no bass duties) and low pass filter the signal to the Gravis I fully symmetrically. This is the key to perfectly blended integration between mains and sub!

There is only one practical downside: You will need to keep the level of the C368 exactly constant and control the volume from the Ultra only. With a fixed volume setting on the C368 you will need to adjust the perfect level for the sub. Should you change the volume of the integrated amp later on, the level of the sub output won't be right.

 

[audiobliss]

Running passive speakers directly from a pre-amp? Doesn't sound like a good idea to me. I disagree in general, though.


Connecting the sub to the WiiM Ultra will enable you to high pass filter the signal to the C368 (no bass duties) and low pass filter the signal to the Gravis I fully symmetrically. This is the key to perfectly blended integration between mains and sub!

There is only one practical downside: You will need to keep the level of the C368 exactly constant and control the volume from the Ultra only. With a fixed volume setting on the C368 you will need to adjust the perfect level for the sub. Should you change the volume of the integrated amp later on, the level of the sub output won't be right.

Well isn’t the signal for the main speakers leaving the preamp, going to passive or active speakers? So that’s what I meant, either a preamp with sub out, or the high level output from the amp.
Since I have to explain in detail.

 

[jed1]

I would prefer subwoofer output from preamp over high level output from the amp - simply because THD level of amplifier output is much higher than that of preamp in general (i.e. most of time true but not necessarily universally true).

 

[audiobliss]

I would prefer subwoofer output from preamp over high level output from the amp - simply because THD level of amplifier output is much higher than that of preamp in general (i.e. most of time true but not necessarily universally true).

Yes, I also prefer and use the outputs from the preamp, but some people like REL believes using the amp outputs has advantages.

 

[harkpabst]

Yes, I also prefer and use the outputs from the preamp, but some people like REL believes using the amp outputs has advantages.

You are right, that's what they keep writing into all their manuals. And BK Electronics as a former REL contract manufacturer kind of picked this up. However, all this stems back from the times when stereo equipment did not have proper subwoofer management. Integration of mains and subs was often a gamble then and a lot of highly questionable recommendations from that area are still around (like "matching" the sub's crossover setting to the "lower frequency limit" of the mains, as if anybody could tell that from a glossy brochure).

Nowadays, REL's recommend way of connecting the sub (from the amp's speaker terminals to the sub's high level input) can even be dangerous and damage the equipment with many class D amplifiers! I'd never take that risk.

Well isn’t the signal for the main speakers leaving the preamp, going to passive or active speakers? So that’s what I meant, either a preamp with sub out, or the high level output from the amp.
Since I have to explain in detail.

One of the biggest advantages of adding a subwoofer is releaving the main speakers from their bass duties, thus not only extending the bass to lower registers but also reducing distortion of the mains.

Not possible with using the high level input.

Why should taking the sub signal from the pre-amp but feeding the main speakers through a power amp be inferior, even in theory? That's the way it is done in modern high end stereo systems and all AVRs. We are offered a tremendous toolset (managing level, polarity, delay and crossover frequency with digital precision), what should we give that up for?

 

[audiobliss]

I have tried it both ways with my Rel s812 sub, I found no advantage to using the high level from the amp, and just more complicated.
I think Rel just wants to sell the Bassline Blue cable.

 

[Kblade97]

Hi all,

Quick question..

Would it be better to connect my Sub (SF Gravis I) to my Wiim Ultra or my NAD C368?

Just thinking about this whilst conducting RC ..

Use the sub out on the nad. Then adjust the sub accordingly. Phase, crossover, volume

 

[Kblade97]

You are right, that's what they keep writing into all their manuals. And BK Electronics as a former REL contract manufacturer kind of picked this up. However, all this stems back from the times when stereo equipment did not have proper subwoofer management. Integration of mains and subs was often a gamble then and a lot of highly questionable recommendations from that area are still around (like "matching" the sub's crossover setting to the "lower frequency limit" of the mains, as if anybody could tell that from a glossy brochure).

Nowadays, REL's recommend way of connecting the sub (from the amp's speaker terminals to the sub's high level input) can even be dangerous and damage the equipment with many class D amplifiers! I'd never take that risk.


One of the biggest advantages of adding a subwoofer is releaving the main speakers from their bass duties, thus not only extending the bass to lower registers but also reducing distortion of the mains.

Not possible with using the high level input.

Why should taking the sub signal from the pre-amp but feeding the main speakers through a power amp be inferior, even in theory? That's the way it is done in modern high end stereo systems and all AVRs. We are offered a tremendous toolset (managing level, polarity, delay and crossover frequency with digital precision), what should we give that up for?

That also depends on the speaker. So I don’t really agree with that. That’s just my opinion. For example, what if you have a speaker that goes down flat to 30 Hz and you have a Rel sub that goes down to 11 hertz -3 bd down. Why would you want to cross over a speaker that goes down to 30 Hz at 80 to 100 hertz and then try to tuck the sub underneath it, you’re going lose some midbass punch. And mess up the midrange which will effect overall sound of the speaker. Especially in the vocal region

 

[harkpabst]

After having a short look at the C 368's manual things seem even more complicated.

The amp has a pre-out which can be set to either sub or pre-out mode. The manual doesn't stete the difference so. Is there aloe pass filter? The answer might be found in the settings, it's missing from the manual.

The.same goes for the speaker output. There is a high pass filter setting "up to 300 Hz". Is it synched with the low pass? Again, the manual won't tell.

Best to look up what's available in the actual settings. If the Ultra is to be used as a pure streaming source and other sources are connected to the C 368, it might actually be better to connect to its sub out.

 

[harkpabst]

That also depends on the speaker. So I don’t really agree with that. That’s just my opinion.

Could you give some more details? You're free to have an opinion but I'd like to understand how you ended up there.

 

[Kblade97]

Could you give some more details? You're free to have an opinion but I'd like to understand how you ended up there.

Run the NAD full range through the pre-outs/sub out and connect to your sub, then adjust the subs phase, crossover, volume and position. Also, are you talking for music or home theater? If you were talking about music only, it would be a huge mistake to limit your speaker running full range and having a natural roll off and adding the sub to it, you’re simply tucking the sub underneath the speaker when it’s playing full range.

 

[harkpabst]

Run the NAD full range through the pre-outs/sub out and connect to your sub, then adjust the subs phase, crossover, volume and position. Also, are you talking for music or home theater? If you were talking about music only, it would be a huge mistake to limit your speaker running full range and having a natural roll off and adding the sub to it, you’re simply tucking the sub underneath the speaker when it’s playing full range.

It's not my amp, I'm asking out of curiosity.

And I still don't understand what you call a "huge mistake". High pass filtering the mains? No, certainly not a mistake but absolutely best practice.

 

[Kblade97]

It's not my amp, I'm asking out of curiosity.

And I still don't understand what you call a "huge mistake". High pass filtering the mains? No, certainly not a mistake but absolutely best practice.

That’s an opinion

 

[Kblade97]

After having a short look at the C 368's manual things seem even more complicated.

The amp has a pre-out which can be set to either sub or pre-out mode. The manual doesn't stete the difference so. Is there aloe pass filter? The answer might be found in the settings, it's missing from the manual.

The.same goes for the speaker output. There is a high pass filter setting "up to 300 Hz". Is it synched with the low pass? Again, the manual won't tell.

Best to look up what's available in the actual settings. If the Ultra is to be used as a pure streaming source and other sources are connected to the C 368, it might actually be better to connect to its sub out.

 

[Kblade97]

It's not my amp, I'm asking out of curiosity.

And I still don't understand what you call a "huge mistake". High pass filtering the mains? No, certainly not a mistake but absolutely best practice.

Again, it also depends on whether using it for music or home theater and your way you would really want two subs because you’re having to crossover higher because of the way you’re crossing over the mains. By taking away their full range abilities

 

[Kblade97]

Hi all,

Quick question..

Would it be better to connect my Sub (SF Gravis I) to my Wiim Ultra or my NAD C368?

Just thinking about this whilst conducting RC ..

Hi all,

Quick question..

Would it be better to connect my Sub (SF Gravis I) to my Wiim Ultra or my NAD C368?

Just thinking about this whilst conducting RC ..

 

[slartibartfast]

That’s an opinion

An opinion based on the difficulty in matching the speaker natural roll off to the sub low pass filter. I could never get mine sounding right before I got the WiiM Amp.

 

[Kblade97]

Hi all,

Quick question..

Would it be better to connect my Sub (SF Gravis I) to my Wiim Ultra or my NAD C368?

Just thinking about this whilst conducting RC ..

Here are my Sonus, Faber Extremas running them full range and using to Rel Stentor 3’s crossed over at 28 Hz to fill in the bottom low frequencies. The Rel Stentor is rated I believe 220 hz-11 hz -3 DB down in room.