HT subs integrated as Large speaker instead of LFE

[chander]

Hi,

A question for you HT enthusiasts.

What are the pitfalls of dual subs integrated with your speakers as large speakers instead of running subs on LFE.

I mean if you have dual subs connected with high level connection and you go for 5.0/7.0 instead of the .1, and nothing connected to LFE. Is that an issue with the HT?

Thanks!

 

[delhite2]

Hi,

A question for you HT enthusiasts.

What are the pitfalls of dual subs integrated with your speakers as large speakers instead of running subs on LFE.

I mean if you have dual subs connected with high level connection and you go for 5.0/7.0 instead of the .1, and nothing connected to LFE. Is that an issue with the HT?

Thanks!

If you setup as above, AVR AFAIK will output LFE to Fronts. But you loose on time adjustment factor. As any adjustments you do will change the fronts and subwoofers at the same time.

Similarly you loose capability to setup a crossover for mains.

Consequently you will also have the full-range fronts fed with LFE from your content and end up probably stressing the AVR more.

 

[chander]

If you setup as above, AVR AFAIK will output LFE to Fronts. But you loose on time adjustment factor. As any adjustments you do will change the fronts and subwoofers at the same time.

Similarly you loose capability to setup a crossover for mains.

Consequently you will also have the full-range fronts fed with LFE from your content and end up probably stressing the AVR more.

Thanks a ton! can you elaborate a little more here?

I thought it will be similar to running lets say a 5.0 where you are using lets say towers?

In this case I am looking at getting dual subs to go with bookshelves and connect the dual subs with high level connection so the LFE out is not connected!

 

[efernand1]

Thanks a ton! can you elaborate a little more here?

I thought it will be similar to running lets say a 5.0 where you are using lets say towers?

In this case I am looking at getting dual subs to go with bookshelves and connect the dual subs with high level connection so the LFE out is not connected!

I think it will sound ok. The Bose Acoustimass AM5 follows this principle which is already a tried tested and in existence. In your case behind the subwoofers, the Crossover needs to be adjusted well so it sounds all in synched and pleasant.

 

[ajuvignesh]

If your AVR routes the LFE signals to fronts, you don’t loose much. Also your speakers and subs should be closer. If your avr doesn’t, you will miss out on signals from lfe channel.

 

[delhite2]

I think it will sound ok. The Bose Acoustimass AM5 follows this principle which is already a tried tested and in existence. In your case behind the subwoofers, the Crossover needs to be adjusted well so it sounds all in synched and pleasant.

Acoustimass is satellite based system.
And there in no time management is needed for bass overlap.
I based my writing on the assumption that OP has fronts with woofers in them like a Floorstander.

Having said that time management is also required in case of satellites because some subwoofers have delay in processing and amplification which can sometimes be around 25-30 ms.

Apart from that the bookshelf would end up sucking more power from the AVR as it will be fed with full LFE signal which as we all know are demanding, and the same leading to more strain on AVR all the while not giving the best sonic output.

 

[efernand1]

Acoustimass is satellite based system.
And there in no time management is needed for bass overlap.
I based my writing on the assumption that OP has fronts with woofers in them like a Floorstander.

Having said that time management is also required in case of satellites because some subwoofers have delay in processing and amplification which can sometimes be around 25-30 ms.

Apart from that the bookshelf would end up sucking more power from the AVR as it will be fed with full LFE signal which as we all know are demanding, and the same leading to more strain on AVR all the while not giving the best sonic output.

The OP intends to use Bookshelf speakers connected to Dual Subwoofers (Powered I assume) through the High Level connection available.

I have connected a JBL Subwoofer 10 inch with Jamo Bookshelf (which has 4 inch woofers) using the High Level connection on a Denon AVR since the LFE port is not working. Had to adjust the frequency behind the sub several times till we found the right blend in sound. Bottomline it is all about adjustments and what one's hearing agrees to. The AVR settings for speakers was changed from SMALL to LARGE.

The AVR obviously being an electronic, will heat up but AVRs based on their specs are also designed for 5.0 or 7.0 for those who don't use a subwoofer at all to perform optimally and hence technical matching to handle the output and overall performance matters for AVR + Speakers being used which should be also considered if trying this setup.

 

[delhite2]

The OP intends to use Bookshelf speakers connected to Dual Subwoofers (Powered I assume) through the High Level connection available.

I have connected a JBL Subwoofer 10 inch with Jamo Bookshelf (which has 4 inch woofers) using the High Level connection on a Denon AVR since the LFE port is not working. Had to adjust the frequency behind the sub several times till we found the right blend in sound. Bottomline it is all about adjustments and what one's hearing agrees to. The AVR settings for speakers was changed from SMALL to LARGE.

The AVR obviously being an electronic, will heat up but AVRs based on their specs are also designed for 5.0 or 7.0 for those who don't use a subwoofer at all to perform optimally and hence technical matching to handle the output and overall performance matters for AVR + Speakers being used which should be also considered if trying this setup.

Yes, it should be done only as last resort.
AVRs are especially susceptible to failure, heat and excess drive is particularly a major reason for any electronic failure. (however as you said 4inch woofers won't be quite taxing on the AVR)

And yes, technically it would work, but theory suggests it's not the best way to handle things, not only AVR health wise, but also because phase adjustment and time delay are totally different things.

Ultimately if goal is to just have drivers being driven and bass being felt then yes go for it.

But if part of the goal is to be as close to being accurate as possible, then avoid if possible.

@chander why not try daisy chain, it works particularly well especially if subs are identical

 

[chander]

(however as you said 4inch woofers won't be quite taxing on the AVR)

The woofers are active, so I am not sure how taxing they will be on the AVR. I am not drawing any power from the AVR for this.

Not sure about Daisy chaining - let me read this up.

Thanks!

 

[delhite2]

The woofers are active, so I am not sure how taxing they will be on the AVR. I am not drawing any power from the AVR for this.

Not sure about Daisy chaining - let me read this up.

Thanks!

Yes, not worried about the Subwoofers load on the AVR as they are, powered as you said and same as we all assumed.
However woofers on the bookshelf also present decent load. And bigger the woofer the more it can draw up current and also interfere with the subwoofer and can cancel bass.
Phase can fix it some extent, but distance setting changes fixes it better.

 

[mbhangui]

Hi,

A question for you HT enthusiasts.

What are the pitfalls of dual subs integrated with your speakers as large speakers instead of running subs on LFE.

I mean if you have dual subs connected with high level connection and you go for 5.0/7.0 instead of the .1, and nothing connected to LFE. Is that an issue with the HT?

Thanks!

If I understand correctly you willbe connecting one sub high level connection to the left channel speaker from the AVR and the other sub to the right channel speaker connection. Your L and R main speakers will be connected to the subwoofer speaker binding posts. After that you will run your AVR calibration with mic connected (Yamaha has YPAO, others have similar DSP calibration programs). And you will be setting the crossover on thes sub itself. The issue I see is that during calibration, the AVR will not detect a subwoofer connected to the LFE and will not be able to set the dB levels for low frequencies during calibration.

 

[chander]

If I understand correctly you willbe connecting one sub high level connection to the left channel speaker from the AVR and the other sub to the right channel speaker connection. Your L and R main speakers will be connected to the subwoofer speaker binding posts. After that you will run your AVR calibration with mic connected (Yamaha has YPAO, others have similar DSP calibration programs). And you will be setting the crossover on thes sub itself. The issue I see is that during calibration, the AVR will not detect a subwoofer connected to the LFE and will not be able to set the dB levels for low frequencies during calibration.

Thanks - yeah your assumption is right. Just curious here though, what happens when you run an AVR with lets say a 5.0? with lets say large Floor Standers like JBL 4367 that can go down to 30 Hz on paper atleast? Is the AVR not processing full signal then and holding back the LFE signal?

 

[mbhangui]

Thanks - yeah your assumption is right. Just curious here though, what happens when you run an AVR with lets say a 5.0? Is the AVR not processing full signal then and holding back the LFE signal? \

I'm assuming that it will send the full signal to the L and R. The subwoofer will anyway pick the full signal and apply the crossover and play the low frequency. My guess is that the low frequency will get boosted, because it is now coming from the speakers as well as the subwoofer. One way to probably mitigate this situation is after the audyssey setup, mark the L and R as small. In Yamaha's YPAO I can do that post calibration. After that manually adjust the subwoofer volume so that it sounds right.

 

[liverpool_for_life]

Is the AVR not processing full signal then and holding back the LFE signal?

Far as I can tell, there is no standard behavior in this instance. Depends on the choices that the AVR provides, if any. What is your AVR?

 

[chander]

Far as I can tell, there is no standard behavior in this instance. Depends on the choices that the AVR provides, if any. What is your AVR?

Hi @liverpool_for_life -
I am currently on Denon X3800H - it has 4 independent sub outputs.
The front 3 (LCR) have been replaced by Kef LS50 Meta. A 3 channel AMP is on the way.

I was wondering if I can replace my Qacoustics Qb12 with dual REL T7is. As much as I love the sub, the size is a real issue

Even though I can run them as 2 LFEs and use them in opposite diagonal directions. I am just very curious about the idea of running fronts as full range with the RELs.

As always the point is that I do not want to buy the subs & realise how bad the idea was.

*****Please note - my HT is a part of my drawing room, it is on one side of a large drawing area which is naturally split in 2, so large sub are a bit of an eye sore. I can replace it with one small sub or at most 2 small subs - hence the RELs.

Thanks!

 

[ssf]

Is the AVR not processing full signal then and holding back the LFE signal?

In Marantz, there is a setting called LFE+Main. You might need to use this to get the LFE signal to the sub.

REL explains this.
https://rel.net/blog/2015-07-20/tuning-guides/how-to-tune-lfe/

Gene explains this even better

So, you can take high level inputs to your dual subs, set the crossover in the sub and run speaker cables from your sub to your main speakers and not miss out on LFE but setting the subwoofer mode to LFT+main and turning off the sub in the AVR.

 

[Decadent_Spectre]

Hi @liverpool_for_life -
I am currently on Denon X3800H - it has 4 independent sub outputs.
The front 3 (LCR) have been replaced by Kef LS50 Meta. A 3 channel AMP is on the way.

I was wondering if I can replace my Qacoustics Qb12 with dual REL T7is. As much as I love the sub, the size is a real issue

Even though I can run them as 2 LFEs and use them in opposite diagonal directions. I am just very curious about the idea of running fronts as full range with the RELs.

As always the point is that I do not want to buy the subs & realise how bad the idea was.

*****Please note - my HT is a part of my drawing room, it is on one side of a large drawing area which is naturally split in 2, so large sub are a bit of an eye sore. I can replace it with one small sub or at most 2 small subs - hence the RELs.

Thanks!

I can't speak about an AVR as I don't use one but any speaker, with the right processing, can be used with multiple other speakers/subs as a multiway system. Many commercial/pro modular systems do this, some (at least used to) integrate a super tweeter. Home manufacturers try to emulate this and fail miserably since the average home user does not have the right processing equipment or the knowledge to do this, as an aside I feel ALL home audio equipment is heavily compromised and not fit for purchase. So your speakers + subs as a "full range" speaker idea is not new and it does work, if done correctly. Perhaps if you include the right processing to the AVR this will become easier to accomplish as you send a full range signal to the DSP if the AVR supports it. With this method it could work. Good luck.

P.S - Would you say your current sub is "much larger" than you'd like or "slightly larger" ?

 

[sandeepmohan]

What are the pitfalls of dual subs integrated with your speakers as large speakers instead of running subs on LFE.

You need to remember that for HT application, that .1 channel is specifically encoded during low frequency passages in the audio. This is done in the sound recording studio. Simply merging the lfe channel into the mains speaker won't give you quite the same effect as a dedicated sub woofer. Amplifier load should be the least of your concerns. More important is that you won't enjoy the movie as much. You'll miss hearing a good chunk of sound.

Even if you did manage a large speaker that can drop below 30hz, you won't hear the same result as a sub woofer playing the low frequency track.

This is less of an issue when it comes to stereo playback as there is no .1 encoded anyway. You use a sub woofer purely for bass assistance. Not over powering the low frequency spectrum to the point where you hear the sub woofer. In HT, the lfe track can play separate to any other channel.

 

[liverpool_for_life]

I am currently on Denon X3800H

From page 229 of your AVR's manual (PDF needs downloading):

Distribution
Adjusts the amount of LFE signal sent to the full-range floor speakers.
o Front/Center/Surround/Surround Back
Off
(Default): Floor Speakers do not play LFE signals.
–20 dB – 0 dB Adjusts the amount of LFE signal sent to
the full-range speakers.
0 This can only be set if “Front”, “Center”, “Surround” and “Surround Back” are
all set to “Full Range” in “Crossovers”.

So, you have the option of either sending the LFE as is or after attenuating it by 20 dB. Unfortunately, this requires that all of the ear-level speakers (not just the mains) be capable of full-range.