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Low Level vs. Combined Low & Hi Level

Etienne A

Established Member
I'm looking for the resident experts opinions on this matter: on certain subs (my BK for example) it's possible to input both low & high levels at the same time - the BK even has separate controls for low and hi for fine tuning the setup.

Certain manufacturers recommend it - others don't make mention of it!

Other than differences in the roll off rate (24db vs 12db per octave) I can't think of any other reason why it would sound different (better or worse) .... maybe (as REL say on their site) the timbre of the amp is carried over to the sub - but isn't that a moot point, since it's low freq. (so timbre won't matter much) and it's gonna go thru' another amp circuit anyway (and mix with a new timbre signature).

I know I should just test it out .... and I intend to, but wiring is a tad complex on my setup so it's gonna have to wait. In the meanwhile I listened to a friend's setup using a couple of MA R90s and a BK Gemini2 sub ... and I have to say that HI sounded "fuller" - not night and day ... but definitely there was something extra. I can only attribute it to a difference in roll-off rate!

Opinions - discuss ...

Member 639844

Former Advertiser
There will be a bit of a difference for films, but there shouldnt be much for music. The main difference will be in the speakers themselves, as with a HL connection they run full range. Its this difference you likely detected. With the HL connection you need to match your sub(s) to the natural roll off of the speakers, and if you run them higher you will get a boosting of bass as well in the range where the speakers and subs overlap a lot, this could also explain your observation.

There is also the point of the fact that you are removing a processing element from your system with a HL connection, which could make a difference too, but that will vary between particular systems.

It could be argued that the speakers and possibly the bass as a whole will sound less accurate via HL, but this could boil down to personal preference as to whether you perceive a degradation or not.

Running combined low and high level connections will make little difference to films, as when the processing is set to a discrete 5.1 operation, you only get the normal low level output anyway. It will make a difference for non .1 discrete material, assuming you correctly set up your system to run via the HL connection method.
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