Bookshelf Speakers

A quick question please

If I set my front speakers to 'Large' on the AMP does that take the Sub out of the equation all together or will it still kick in at certain frequencies?

 

i think it still works as it would with them set to small, but the main speakers will also get those frequencies. But i could be wrong.

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On my amp I set the fronts to large (I don't have a sub), but forgot to turn off the sub in the amps menu. I only got some of the bass from the fronts, until I went into the menus again and set "sub out" to off again. Therefore I surmise that with the fronts to large, you will still get plenty of bass to the sub, just don't know where the cross-over point in the amps mind will be..... Setting fronts to small (with sub) seems to be the prefered option on this forum.

 

If you set the speakers to large, a full range signal would be sent to the front speakers with only the LFE signal being routed to the subwoofer.

 

Ian

I have the denon 3802

If I set fromts to large I then have the option to set either:

LFE

or

LFE + MAIN

Any idea what the difference is?

 

On the point referring to the the 'norm'.

Surely if you have speakers that are capable of the a full range (i.e. 60 hz to 20khz) then the setting should be set to 'Large' to get the benefit of their full range?

Otheriwse I could make do with some puny little satellite speakers?

 

petrolhead, I am ashamed to say that Jase has answered this question so many times but as I have mine set to small I have never taken much notice of his reply and can't remember.

scrapbook, 60Hz would not be considered the bottom end of a full range signal and my expensive M&K speakers don't go below that yet are not "puny satellite speakers" either.

If you have a decent subwoofer it should be capable of handling the bass signals better than what you call "full range speakers" although there are expensive exceptions to this rule.

You don't say what kit you have but if you have a subwoofer trying setting the fronts to small and see how you like the sound.

 

some speakers (like the Gallos) can't take a full range or large setting and make a point of this in the documentation, the sub is there to deal with the low freqs.

 

Yep sorry when I said Puny i was referring to tiny satellite speakers that generally kicked in at about 100hz or so. I appreciate that the bottom range of a sub is well below 60hz.

So are you telling me there are no advantages in having speakers that are capable of a wider range if a good sub is present?

I have M72's fronts and centre

 

Okay, let me see if I actually understand this myself.

There are two separate scenarios you need to consider in terms of the input:

1) Something like a DTS or DD film track, which includes a dedicated subwoofer channel. The other channels won't contain anything below (typically) 80 Hz.

2) Something like a stereo or Dolby Prologic II setup where there is no dedicated subwoofer channel, and all channels go all the way down.


If you set a speaker to "Large" then the processor will send to it any signal originally intended for that particular channel, regardless of frequency. If you set it to "Small" the the processor will reroute any signal below a given frequency to somewhere else, ideally a subwoofer. You often also have the option to set a subwoofer option to "off", which would mean there is no subwoofer present.

So, some examples:

1) You don't have a subwoofer at all. Your front speakers are floorstanders, centre and rears are satellite speakers. In this case you should set the subwoofer or LFE option to "Off", the front left and right speakers to "large" and the other speakers to "small". For a 5.1 source the subwoofer channel will end up being redirected to the front speakers. For a stereo or 5.0 source (such as DPL II) any bass signal intended for either the front left or front right speaker will go to the speaker in question; any bass signal on any other channel will be redirected to the front pair.

2) As above, but with a subwoofer. In this case you would want to set the sub/LFE option to "on", so that the subwoofer channel for DD or DTS gets sent straight to the subwoofer. Satellite speakers are set to "Small", so any signal that would otherwise be sent to them in (say) DPL II mode will get redirected to the subwoofer. Now, what about the fronts? You might want to set the front speakers to "large", in which case any bass sent to them in DPL II or Stereo mode will go straight there; or you might want to set them as "small" and redirect their bass to the subwoofer, because the sub may well do a better job of it.

3) If all surround speakers are satellites then should all be set to "small".

In addition you may also be able to play with the cross-over frequency for speakers that are set to "small". So if you had a pair of floorstanders at the front that are good down to 60 Hz but satellites at the back that only go down to 80 Hz then you could redirect anything below 80 in the rear channels, but only anything below 60 in the front channels.

A really heavy duty subwoofer, as Ian says, goes way lower than 60 Hz. The famous Velodyne HGS-18, for example, hits -3dB at 15Hz, but makes some noise lower still. It's most unlikely that a floorstanding hifi speaker will be able to achieve this. Of course you do have to rely on the processor's bass management working - some processors might make enough of a hash of it that you're still better off sending front bass signals to the front speaakers and losing the low end.

 

DD/DTS has 5 full range channels + an LFE channel or am I reading your post wrong, if so I appologise.

 

I think we need a tutorial about Subs, Xover, Denon 3802 etc

Any takers --- Jase?

 

Yes - M&K don't make any speaker that officially goes below about 80Hz but we are talking home cinema use.

Obviously there are exceptions but they are expensive.

 

That may be true in theory, but in practice I suspect you won't get much low frequency stuff in the main 5 channels - if you do then it rather defeats the purpose of having a dedicated low frequency channel in the first place.

This does become an issue, of course, if you have cheap satellites that bottom out above 80 Hz. In this case stuff from the main 5 channels would obviously need to be routed to the subwoofer.

I suspect the answer to that, as with so many things in life, is "it depends".

I would speculate that (for the reasons discussed above) for home cinema purposes you're unlikely to benefit from having speakers other than the sub go below 80 Hz, because the soundtrack will have been mixed in such a way as to push all this stuff into the LFE channel anyway.

If you're listening to a stereo source (or anything with no discrete LFE channel) then the processor has to extract the bass components from anything up to 5 channels, combine all these components into a single signal, and leave the non-bass aspects of the original signals untouched. How well it is able to do that will vary. Plus the quality of the sub will vary.

I think it's a question of "whatever sounds better to you", really. But it's reasonably safe to say that, no matter how low your front speakers go, they won't go as low as your sub does (as Ian says there are expensive exceptions) so a certain amount of redirection will almost always be a good thing, assuming the sub is of reasonable quality.

 

Nicolas

While that's one way of looking at it, IMO it's not quite as simple as that.

Firstly, the LFE channel (at least in DD) has an extra +10dB of headroom over the other channels, for those really meaty low end effects (Digital full scale is AFAIK - main channels 105dB, LFE channel 115dB).

Another consideration is of course Dolby Digital downmixing, where the .1 LFE channel is completely discarded. If all the bass below 80Hz in a soundtrack was simply shoved into the LFE channel, you'd end up with a pretty tinny downmix
Also, there would be little need for bass management in AV amps/procs/recv'rs - the recording engineer would have effectively done that for you.


In real life, as is so often the case, things may get a little muddied though. Some soundtracks my well be mixed as you say, but if it's mixed according to Dolby guidelines, it certainly shouldn't be done that way - they encourage using the LFE channel only when it's needed (which, fair enough, is fairly often in many films these days )

 

That seems a pretty silly way to do downmixing but I dare say you're right.

Well, yes, but that would be desirable, wouldn't it? He could take as much time and effort as is needed and would have much higher grade equipment, while your processor is expected to do it on the fly. You'd still need bass management for sources lacking a dedicated LFE channel, or for speaker systems where the satellite cut-off frequency was too high.

 

I´ll leave that to the likes of Uncle Eric, Nic Rhodes, Charlie Whitehouse et al. All have far greater technical knowledge than me.