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Are High Level inputs essential for music?

Meeko

Established Member
Do subs with low-level inputs peform well with music? I notice that the B&W subs seem to have low level inputs only. I've found an ex-demo ASW800 in black ash, which matches my Monitor Audio RS8s. Would this be a good choice?

I would use it for 60% music, 40% films. I have a Denon 3806 amp which can be configured to send LFE+Main to the sub.

Thanks all
 

Jammyb

Prominent Member
I'm interested in this as well as I assume if the amp is in 'stereo' mode then it will senf signals to the sub and if it's in 'direct' mode (which I currently always use for music), then it will not?
 

Lewis123

Established Member
BK subs let you use both types at the same time.
 

Ian J

Banned
If your main speakers are set to small my amp will send anything below 80Hz to the sub in direct mode too.

High level inputs are only essential when connecting to a stereo amp that doesn't have any pre-outs as it won't have a dedicated subwoofer outlet.

Most of us don't seem to bother with the high level inputs judging by a recent poll on the forum.
 

Etienne A

Established Member
I would imagine the general idea is that to use 'direct' 'pure' (or whatever) stereo modes, you just have to connect the sub to high-level as you won't get anything on the sub out. I'm sure there are exceptions thou'!
 

Nimby

Distinguished Member
In my opinion the advantage of using high level connections means that you are much more likely to be using a high quality stereo amplifier for your music listening. :smashin:

Better than trying to listen to music via an AV receiver. Even high-end AV receivers don't do such a good job with music as a dedicated stereo amplifier of suitably high quality. :thumbsdow

Leaving the speaker signal well alone and just underpinning the lower frequencies of your speakers offers sound quality benifits. Only the subwoofer is subjected to filtration. :smashin:

I believe that attacking your main speakers with any sort of filtration (or worse, a passive crossover) will cost you in terms of sound quality. :thumbsdow
 

chrisgeary

Prominent Member
of course there is a flip side to that.

if you use high level only for music, and you have a less than perfect room, you won't be able to EQ bass with your sub. you may get somewhere if you have a parametric EQ onboard, but most don't.

therefore the benefit of using highlevel is the benefits of using your stereo amp
the downside if lack of bass management

the benefit of using your AV amp is the ability to bass manage using a BFD for example.
the downside is inferior sound quality compared to your stereo amp.

if you have a particularly good AV amp/processor, I think using low level and bass management is the obvious choice.
 

Mr Cat

Banned
I use the speaker level when I'm listening to cd's - I find thats much better (IMO) that using the phono connection...

I seem to recall that if you use speaker conenctions then the amp from the sub is used, and the amp of the amp is used phono connections...
 

John Simon

Prominent Member
Mr Cat said:
I use the speaker level when I'm listening to cd's - I find thats much better (IMO) that using the phono connection...

I seem to recall that if you use speaker conenctions then the amp from the sub is used, and the amp of the amp is used phono connections...

Surely the amp from the sub is used in both senarios?
 

Nimby

Distinguished Member
Mr Cat said:
I seem to recall that if you use speaker conenctions then the amp from the sub is used, and the amp of the amp is used phono connections...

I think you'll find that an active subwoofer is driven by its own amplifier regardless of whether it is connected by high or low level connections.

Only a passive subwoofer would be driven by the stereo amp or AV receiver. Since a passive subwoofer is basically just another loudspeaker driver in a specially designed enclosure.
 

Mr Cat

Banned
ok, no probs - thought I read it on some forum somewhere!
 

Fibretear

Established Member
i have an old denon av1801 and only about a month ago went from using just a low level connection to using both high and low (rel sub)
I would say that for music the high level is better (for me) for music because ifs much easier to set the crossover to match the front speakers - so you set the fronts to large and the crossover on the sub to take on anything the fronts cant deliver. you must have the stereo mode set to direct otherwise the amp will send the base to both high and low level and you will get bass doubling - my 1801 does not do this so i have the sub set to off when using stereo and turnit back on when using a 5.1 source - which is a tad annoying but i understand newer amps sort this out.
The low level is connected at the same time and takes all the .1 and low freqency sound from the speakers set to small.
it took me ages to get the volumes right when using both at the same time but i think it was worth it in the end
G
 

Meeko

Established Member
I've just spoken to a B&W engineer from their head office and he recommended setting all speakers to small - even if your fronts are full range. He advised that for my MA RS8s (33Hz-30Khz), the crossover should be set to about 50-60Hz. This is where the sub takes over.

He said the reason you wouldn't set the sub to carry on at say 32Hz is that all the sub will do is "bang" and not be very tuneful. It would be better to set the crossover higher up. This will also improve the sound as the AV receiver is not working as hard.
 

niceguy235uk

Prominent Member
The whole idea of a high level connection IS to use with Stereo Direct.

This enables the sub to reproduce exactley what the speakers are (albeit the low end) and therefore time and integrate better with music.
 

dazed&confused

Prominent Member
I'm starting to get quite confused by all this.:confused:

I currently have just one lead, a Mark Grant subwoofer coax phone cable, connected to the line level input of my sub. I would like to improve integration for music, because my sub is not ideally placed, being in the corner, down the side of the sofa, on the opposite wall to my fronts. It's probably not only a case of positioning, because sometimes I don't notice localisation but can still annoyingly distinguish the sub from the front speakers in the way of two obviously seperate beats/rythms emerging, even though they are pretty much in time.

If I wanted to try my sub hooked up at speaker level for stereo use, how would I do this? Would I need to run four wires from my amp, connected to the same terminals as the front speakers? And if this was the case, would regular speaker cable be ok, or should I be using similar stuff to that used for the line level sub input ? (by the way, I originally purchased the Mark Grant screened coax cable to overcome a permenant hum, which thankfully worked).

In this scenario, what's to stop frequencies lower than the cross over setting on the sub from going to the fronts as well? The cross over setting on the amp wouldn't work, would it, since I'd be needing to use pure direct mode? In which case, how would the cross over setting on the sub filter things out to front speakers connected in parallel? I'd really want to prevent low frequencies overworking the amp/satellite link and distorting the image.

If I used a different mode to pure direct, say 'straight' for example, then wouldn't the amp then be sending a signal at line level and speaker level simultaneously, and therfore confound the image at teh very least? Similarly, in the above set up, when I wanted to watch movies or play SACD wouldn't the amp be trying to use line level and speaker level simultaneously?

Perhaps the only option would be to use a seperate stereo amp for stereo music, connected at speaker level, and the AV amp connected at line level for movies, SACD, and prologic II music?

But even then, with a stereo amp, if Iconnect speakers in parallel with the sub at speaker level then how would the crossover come into effect? And even if it could, would this not deteriorate the performance of the AV amp for it's SACD, prologic music, and movie duties since the manual gives a claer instruction to set the sub crossover knob at the max, and let the amp do the work?

:confused: :confused: :confused:
 

Meeko

Established Member
I wonder if this is due to your AV Receiver not providing the roll-off to your mains exactly in time with them. This is a little worring as I was going to rely on my Denon 3806 to provide bass to my sub without any high level connection. What receiver do you use?
 

Nimby

Distinguished Member
dazed&confused seems to be having problems with integration. Most proabably because of the poor siting of his subwoofer. Placing a subwoofer in the wrong place for furnishing reasons or to obey a partner is like wanting to drive your car permanently on the wrong side of the road! :rolleyes:

I doubt that using high level connections will make the slightest difference to his sound quality. High level connections really only provide a small thereoretical potential gain for those going the pure stereo route and demanding the best possible sound quality. :cool:

Many millions of other music lovers worldwide will get on with enjoying their music using low level connections. Either through their AV/HT system or via a stereo system using Pre-out with a normal phono cable. High level connections also allow the easy use of a subwoofer when a stereo amp doesn't offer a Pre-out socket. :)

Situation, situation, situation. Bung your sub somewhere between the speakers when you want to use it. Bung it back in its corner out of sight when you're not using it. Or just turn it down until it doesn't bother you any more. :smashin:

Still not happy? The run some lighting flex between the backs of your speakers and the sub's high level connections. Just to see if it helps. Though I doubt it will achieve anything except making the place look untidy. :suicide:
 

dazed&confused

Prominent Member
Thanks for the replies to my post and sorry if I'm now hijacking the thread. I think my question is relevant though. I do appreciate that using a speaker level connection is unlikely to improve integration. However, I would still like to use a seperate stereo amp from my AV amp for stereo music, but still use the sub and also have the sub connected up for movies. So all the questions above still stand. Thanks.
 

Nimby

Distinguished Member
I don't think you're highjacking the thread since you are covering much the same ground. Your problem probably applies to many other AV/music fans who aren't allowed (or can't) fill the room with your kit in exactly the correct, theoretically-desirable position.

Going back to your original (tale of woe) post. It seems you are confused over the correct use of high level connections. At least you are according to my own philosphy of stereo sound quality.

With high level connections you should always leave the speakers to play full range. Then roll the sub off to match your speakers' own bass roll-off point.

So the sub just takes over at the frequencies below where your speakers run out of steam in the bass. In practice and in real rooms you can't trust the manufacturer's figures for -3dB. Because they will probably be different in different rooms. You should check yourself with sinewaves and an SPL meter to be totally accurate. Even then you could still find better integration from alternative roll-off frequency points on your subwoofer.

If you don't follow my philosophy strictly then you might just as well use low level connections. Since you are messing with your precious speaker signal if you roll them off artificially above their natural (in-room) roll-off point.

The -3dB point should be measured from the listening position. Nowhere else is relevant as far as integration is concerned. It doesn't matter a jot if the response is ragged in another place in the room as long as it's okay from your comfy chair. :)

You may ask what you do if your speakers go lower than the lowest roll-off point setting on your subwoofer. The answer is to set the sub to the lowest point and do a frequency response test run from the listening position. In my case I was lucky enough to get away with a 60Hz sub setting on 40Hz speakers. The 40Hz setting wasn't optimum in my system, in my room. Yours will not be the same!

If you arent so lucky you could play with your phase control on the sub to get better integration. (again by listening from your comfy chair) Nowhere else in the room matters as long as you're happy from your usual seat. Nor will you be able to hear phase changes from beside your sub. The phase control delays the sub's output. Hopefully to match your speakers.

Imagine starting two CDs out of step with each other. One CD plays through the sub. The other only through the speakers. The perceived delay is totally dependent of your listening position. (due to the speed of sound and distance the sound has travelled from unequal distances to reach your chair) So you have to be sitting where phase matters to notice any difference at all. In other words you have to be sitting where both CDs seem to be playing together after the delay of the sub catches up with the speakers. (Which were further away)

In fact adjusting your sub's phase may be exactly what you need for your assymetric (lop-sided) subwoofer position. Bung some bassy music on and have somebody sensible slowly adjust the subwoofer phase control while you sit looking pleased at the improvement from your comfy chair. Just don't blame the knob twiddler if it doesn't help! Or they'll never help you with your silly music system, ever again. ;)
 

dazed&confused

Prominent Member
I think I understood some of that :) Unfortunately, my sub phase control has only two positions. I'm not sure what the relevance of 3db is. My (highly limited) understanding of bass management has been that I should set my speakers to small, and have low frequency signals going only to the sub rather than to both fronts and sub, regardless of input level to the sub.

Sorry for being so thick, but I am still not understanding how I would connect up a stereo amp to the sub. If I used the preouts, say, how many leads would I need and to what connections on the sub?

Thanks
 

Nimby

Distinguished Member
dazed&confused said:
I think I understood some of that :)

That's progress. :)

Unfortunately, my sub phase control has only two positions.

No problem. It simplifies matters. You only have a 50% chance to getting it wrong. Try both settings and choose the one that sounds most bassy from your usual listening chair or sofa. :smashin:

I'm not sure what the relevance of 3db is.

-3dB is only a convention that you see a lot in the magazines and adverts for audio products. It means a sub or speaker is fading away in output due to its design and can only play at half its normal power at this particular frequency. So it gets quieter than its normal level at falling frequencies until it goes so low you can't hear anything at all. -6dB, -12dB, -18dB all mean the output is getting progressively quieter and quieter with falling frequency.

You may still be able to hear some of these lower frequencies if the system is playing very loud. But those lower frequencies just won't be as loud as frequencies above the -3dB point. Which the speaker or sub can handle normally.

So next time you see a magazine review for a pair of floorstanding speakers saying 38Hz (-3dB). You will immediately know that the speaker or sub is rolling off in output below 40Hz. It is at half its normal output (loudness) level at 38Hz. 35Hz may be at -6dB. 30Hz may be at -12dB or -18dB. So you wouldn't expect to hear powerful 30Hz sounds coming out of these speaker even when they're playing loud.

My understanding of bass management has been that I should set my speakers to small, and have low frequency signals going only to the sub rather than to both fronts and sub, regardless of input level to the sub.

Sounds fine. Unless you have very big, powerful, bassy speakers when you might choose to share the bass load between speakers and subwoofer. Otherwise just use the subwoofer for the bass.

I am still not understanding how I would connect up a stereo amp to the sub. If I used the preouts, say, how many leads would I need and to what connections on the sub?

If your stereo amp has pre-out sockets then just use a single phone to phono cable between one amplifier Pre-out socket and your sub's Low Level Input connection socket. If there are two phono sockets on the stereo amp there is really nothing to gain by running two cables to feed two input sockets on the subwoofer.


Pleasure. Don't put yourself down. Everybody has to start learning a new subject from scratch. There are no stupid questions. Only stupid answers.

You are asking basic questions that a great many others are probably grateful for. Because they are also new to the subject but were too afraid to ask themselves.

So don't be afraid to ask if there's still anything you don't understand. That's why we hang around here. Just comparing the size of our subs gets boring after a while. Even if mine is bigger than all of theirs! ;)
 

antz

Established Member
Pleasure. Don't put yourself down. Everybody has to start learning a new subject from scratch. There are no stupid questions. Only stupid answers.

You are asking basic questions that a great many others are probably grateful for. Because they are also new to the subject but were too afraid to ask themselves.

I'll second that. I never completely understood the -3Db thing until it was simply explained here.

Thanks

Antz
 
S

steve998

Guest
i will third that!! :thumbsup:

if my main speakers roll off point are listed as 59hz +/-3db (B&W 601S3) should i have my sub roll off at 59hz as well, OR should I have it a bit higher to fill on the + or - hole? I did not know that 3db made so much difference.

I obvioulsly dont want bass doubling, but i dont want a hole either... I think i need a sound pressure meter!
 

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