A quick question -- is there a benefit I would miss out on by running my powered sub in series with my main speakers (basically ignoring the sub pre-out on the receiver)? My front speakers have a crossover at 120 Hz and I believe the receiver I just ordered has a sub pre-out ceiling of 90 Hz. Rather than miss out on a range of sound I figured I'd ignore the pre-out once I set up the new system. Thanks!

Steve,

Good question! I don't know either.

Many times when I go to hear a set of HT speakers the pre-out is never hooked up.

Does anybody out there know what's the best approach? I have a Dolby Digital Receiver. Should I run my front surrounds thru the powered sub-woofer?

Dolby Digital has a specific track called the LFE track or Low Frequency Effect track. I cannot imagine you buying a new reciever without DD but, if you are using a Dolby Digital Reciever you would be missing out on LFE, if you don't have a DD reciever then yes you would have it connected correctly. But with if using Dolby Digital you should use the pre-amp out. Some sub will let you use both HI level and Low level inputs at the sametime. And some equipment has bass redirection such as my Sony EP9ES pre-amp. Depending on the sub and the size of your front speakers 90hz might be good or bad just depends.

I think the answer depends on the type of speaker system that we are speaking about. Sometimes if the sub is matched to the particular pair of front speakers, the LFE crosssover may not sound as good as a direct connection. I have a pair of Genelec 1029A front channels along with a matched 1091A sub. When connected to the LFE out, there was a definite problem. I reconnected and fronts thru the sub, set the receivers control panel for LFE to "Large" and "No Subwoofer" and
it sounds great. The Genelecs are all pre-amp level, however. Use your ears! Good luck!

Steve, which receiver are you getting? Bass management is the buzzword here; some receivers let you divvy up the bass between the subwoofer and the front mains, in several ways. Whatever you do, make sure that you can get the LFE signal to the subwoofer, or you will miss a big part of the Dolby Digital 5.1 experience.

Hi guys,

Whether or not you run a sub inline with the fronts or out from the pre-out depends on a couple of factors. And this is not to say that you can't do both.

Generally use of an inline sub is when the sub is a passive or unpowered sub. So you need to use your receiver or amp's power to run it. In such a set-up you would do as "jazzly" did, and set the bass management to to large speakers and no sub.

Use of the sub or LFE pre-out means you are running a sub that has a built in amplifier because it's just sending out a line level signal.Now here is where a little confusion comes in. What output you get from the sub pre-out depends on how you set-up bass management.If you set for large speakers ( full dynamic range ) with a sub, then only LFE info will be sent to the sub. Meaning that you will only hear the bass your speakers are capable of producing.So check your speakers capabilities and set bass management accordingly.

Now sub bass takes alot of power to hear. This is why many recommend setting bass management so all speakers are small ( meaning a dynamic range of 80 Hz approx. and up ) with a sub. What this should do is send all sub 80 Hz bass, including any LFE, to the sub, thus relieving your receiver or amp from having to drive the low end.

Now ,of course,what you actually do will depend on the power your amps have and the effiency of your speakers.
Not to mention the time involved experimenting.

Hope this helped a litle

Paul

...and here's an aspect of this subject I'd like to hear some thoughts on: just how directional is low bass? If you send all signals below, say, 80hz to the subwoofer, can you hear it's position and will it distort the soundstage?

I can't in my room, which is only 15 x 11 x 10.( 1550 cu ft ).

Check out the the "Subwoofer placement" thread. There's a link to an interesting page on the subject of subs and placement.

Paul

I guess I should have known that I wouldn't get away without posting specs. ;-) Pertinent equipment is as follows:

Receiver: Yamaha 5150
Subwoofer: Infinity BU-80
Front Satellites: Gallo Nucleus

As I understand it, the Gallos have a crossover at about 120 Hz. The Infinity has a variable crossover ranging from 50-150 Hz. Right now the speakers are set up in series from my old Sony Pro-Logic receiver which doesn't have a sub pre-out.

If I set the receiver up as speakers being small and LFE going to the sub pre-out, I think that all sub 90 Hz signals will go to the sub and anything above 90 Hz will go to the mains. Unfortunately because of the high crossover I'll be missing out on quite a range of the signal. Is there a way I can set up one channel on the LFE and the other through the main output and still be happy? Or is that a no-no that'll mess up my system? Cooltoff mentioned that it may be possible to set it up with both -- which is why I'm asking. Thanks in advance everyone!!

Hey Steve,

Are all five speakers going to be these Gallo's?

Paul

Let's say I have a DD receiver and I install the front and rear surrounds and center channel directly to the receiver outputs. Then I install the Sub-Woofer to the receiver's LFE out.

What happens when I listen to a Dolby Pro-Logic (not DD)? Does my sub-woofer do anything?

Again, it all depends on how your receiver handles Bass management and how you set it up.

DPL programming is a matrix extracted 4 channel surround format that does not include a separate LFE channel.

So, depending on your receiver's BM, you may not get any output from a sub hooked up to the LFE output while listening to Pro Logic material.

Check your owner's manual for details on how it handles bass management for each type of decoding that it performs.


Paul

Steve, you say the Gallos have a 120hz crossover. Do you mean 120hz is the low end of the speaker's freq range, or is that an internal crossover point in the Gallo between drivers?

Specs from the Gallo homepage is as follows:

Frequency Response:
Subwoofer 32Hz to 120Hz
Micro Satellite 120Hz to 18Hz
Sensitivity 92 dB
Nominal Impedance 8 Ohm
Power Handling 50 Watts

Surprisingly good sound from such tiny speakers (blows the Bose speakers away). The spec above is for the Gallo passive sub, as stated before my sub is an Infinity BU-80 powered sub.

I have a HT setup using the Gallo Micros and a Yamaha 2092. Sounds very nice for both HT and music (would not use these speakers in a large room). I am using the Gallo passive sub with the fronts (the crossover is acheived at the sub). I set the receiver so the main speakers are Large, center and surrounds are small, and no sub. This sends all bass to the passive sub. Since the micros have virtually no bass capability, even with a powered sub you will have to have a similar setup. If you ran only the LFE pre-out to the sub, you would be missing a lot of bass. I am not familiar with the setup of the Infinity, but instructions with your sub should tell you if having both the L&R speaker out and the LFE pre-out connected to the sub will be of any benefit.