Not being an electronics wiz...could someone explain to me what actually happends when I hook up my REL Quake sub to my LM3886 amp using high level input to the sub. Will the load on the amplifier be easier as the subwoofer will take care of the low end, or will the amplifier deliver low end to both my main speakers as well as to the subwoofer?
As a followup question: What's the best way of splitting the low level signal so that I may feed the subwoofer with a low level (mono) input and also feed the LM3886's? Currently I only have a passive alps potentionemer acting as my volume control between my source and the stereo chipamp, and in a prefect world I would like to split the low level signal after the volume contol, without involving a crossover filter.
Regards,
Fredrik
As a followup question: What's the best way of splitting the low level signal so that I may feed the subwoofer with a low level (mono) input and also feed the LM3886's? Currently I only have a passive alps potentionemer acting as my volume control between my source and the stereo chipamp, and in a prefect world I would like to split the low level signal after the volume contol, without involving a crossover filter.
Regards,
Fredrik
Im sure you realize that the subwoofer does deep bass, and that takes a good deal of power, which your 3886 does not have. If you run you amp into the subwoofer, then from the subwoofer to your speakers, the subwoofer will do the bass, but it will prevent the bass signal from reaching your speakers, thus taking a good deal of the work away from them, allowing them to play louder, and perhaps sound better.
Splitting the line level signal is a much more complicated affair, and you will almost certainly not want to do this, unless you have a pre amplifier with a sub out. Even if you do, you may notice that the sub will somehow always sound tighter for stereo music if you use the high level input. Try it for yourself sometime.
If you are after the best possible sound quality, what you want to do is run two sets of speaker wires off your amp - one to the high level in on the sub, and one to your speakers. This way your speakers will be running full range, and the sub will only be filling the really deep stuff, which is what it does best. Try it both ways - you will likely find this way sounds more perfect. However, you will have better dynamics running it "through" the sub, and if thats whats lacking, it could be just the ticket.
Splitting the line level signal is a much more complicated affair, and you will almost certainly not want to do this, unless you have a pre amplifier with a sub out. Even if you do, you may notice that the sub will somehow always sound tighter for stereo music if you use the high level input. Try it for yourself sometime.
If you are after the best possible sound quality, what you want to do is run two sets of speaker wires off your amp - one to the high level in on the sub, and one to your speakers. This way your speakers will be running full range, and the sub will only be filling the really deep stuff, which is what it does best. Try it both ways - you will likely find this way sounds more perfect. However, you will have better dynamics running it "through" the sub, and if thats whats lacking, it could be just the ticket.
Last edited:
Thanks for your reply NAC, however I am a bit confused by your reply; I forgot to write that the sub I'm using is a powered one, and it has both high level input as well as low level input. Indeed, the manufacurer also suggests that using the high level input will give the best sonic result. Also, the main speakers are not fed through the crossover of the sub, in fact there are are no output option on the sub, so my main speakers are connectet to the LM3886 output, and the subwoofer is connected to the same output, hence the question about what the amp is feeling as being its load. The speakers are a pair of high efficiency (95 dB) transmission line's, but due to the nature of the design I use the sub to give me a tighter bass response, not more depth.
Now, this was a long description in a foreign language 😉, I hope it makes sense...
Regards,
Fredrik
Now, this was a long description in a foreign language 😉, I hope it makes sense...
Regards,
Fredrik
I'm sorry. You are a more sophistocated poster than I thought.
The high level input of the subwoofer will give a very high impedance, and will therefore have a minimal effect on the signal. You only need to make sure that the speaker cable to the subwoofer has a low capacitance.
Forget about the line level input. The only substantial thing you can do is to get rid of the plastic feet on the sub and replace them with spikes.
The high level input of the subwoofer will give a very high impedance, and will therefore have a minimal effect on the signal. You only need to make sure that the speaker cable to the subwoofer has a low capacitance.
Forget about the line level input. The only substantial thing you can do is to get rid of the plastic feet on the sub and replace them with spikes.
do you have the operator/user manual for the REL?
If not, you should question where you bought this potentially stolen equipment.
Andrew what's your problem? What kind of question is that ?!?! Are you seriousely implying that I handle stolen goods?!?!?
Of course I have the manual, and you would know that I do if you ever read a manual from REL - They are paper thin and contain only the most basic information on how to hook up the sub. The question I posted had nothing to do with that!
/Fredrik
Of course I have the manual, and you would know that I do if you ever read a manual from REL - They are paper thin and contain only the most basic information on how to hook up the sub. The question I posted had nothing to do with that!
/Fredrik
NAC - OK thank you for the clarification regarding the load, that's what I was after!
Cheers,
Fredrik
Cheers,
Fredrik
2-way electronic crossover. It will split the output from the source to a low and high frequencies. Lows for the sub, higher ones to the LM3886 amp.
What's the source? Perhaps it has some cross-over capabilities.
So if I'm running stereo LM3886 amp, I'll have to connect the receiver output to my stereo speakers but with additional wires to my sub. I'm a lil bit confused over this part... Should I connect two sets of wires (L+L- and R+R-) from amp to my sub or just either L channel alone is enough?
Your 3886's will be handling the full range signal to main speakers, which is not good if you want that load taken off them and the main speakers and into the subwoofer. In other words the main speakers may overload on subbass and probably sound dire or even overheat and fail. This is why using the high level inputs to the REL isn't a great idea IMO.
That's sort of the definition of a crossover - a filter that splits low from high frequencies, so you need a cross over (but it only need be line-level, ie active crossover). In fact the subwoofer will ignore high frequencies so you only need a high-pass to strip lows from the 3886's inputs.
But trying to drive a passive high-pass from the output of a volume control is problematic - the source impedance varies a lot. Adding a passive L-pad before the high-pass can fix this but reduces signal level too.
The REL seems to take L + R low level inputs, so that's easy:
vol control -> L-pad -> low level inputs
Also L-pad -> high-pass RC filter -> LM3886's
But that assumes the REL's cross over is 1st-order (unlikely), and that the loss in signal level of an L-pad is OK.
Really a full active crossover is the best approach, flexible and allows proper matching of slopes without having to take measurements and make too many compromises.
- Status
- Not open for further replies.