2 Crossover settings?

[Droogie 2001]

After reading a lot of posts recently about Crossover frequencies I thought it was time to review mine as I have a Denon 3802 receiver and the KEF eggs for about a year now and have not amended them much since.
I want to ensure I am getting the best possible sound out so I need to ask several quick questions…
I have set speakers sizes to ‘small’ on the amp and the sub to ‘On’.
I have changed the Denon’s crossover to 120hz and moved the subs crossover to a fully clockwise position.
My question is if the Denon is routing all the frequencies below 120hz to the sub why does the sub have its own crossover? I understand if you were to use the high level inputs etc and connect speakers directly to the sub this would be the way you would control the sub. Is this crossover effectively redundant when using an amp/receivers own crossover setting?
Secondly can anyone recommend a good balance for this setup? I know that this can be down to person choice but if anyone could give an indication as to how it will affect the sound would be most appreciated.

Thanks

 

[Ian J]

Originally posted by mraggett
Is this crossover effectively redundant when using an amp/receivers own crossover setting?

Yes as long as the amp's crossover is accurate.

 

[bob007]

Originally posted by mraggett

My question is if the Denon is routing all the frequencies below 120hz to the sub why does the sub have its own crossover? I understand if you were to use the high level inputs etc and connect speakers directly to the sub this would be the way you would control the sub. Is this crossover effectively redundant when using an amp/receivers own crossover setting?
Thanks

The subs internal xover is also used when speakers are set to large.

From what I understand I don't think is totally redundant, I would say it's still active, it's just the amp has priority in sending the frequencies via it's xover. I might be wrong.

My question would be: If it was redundant why set the subs xover to max?

Just for a matter of intrest, the sub I have has the option to use an internal/external xover or both.

As for setting up for the best sound, you are nearly there, speakers small and sub set to on and 120Hz xover, just a case of getting the right balance of bass. I found the spl meter helped me, set all levels to 75db and adjusted the bass from there. If you have no meter then set it up with a soundtrack you know well, or a CD, you don't want it to rule the sound just enough to complement the system, you will know when you have the right balance. It will take a bit of time to get it right.

 

[EvilMudge]

My question would be: If it was redundant why set the subs xover to max?

The filter in the sub doesn't have a perfectly linear response. It doesn't cut out all the waveform with frequency components higher than the cut off, it just reduces their intensity to about 1/16th those below the cut off. Around the crossover frequency you can get attenuation of frequencies you might want to reproduce, ie setting it to 80Hz doesn't mean you'll get the full 80Hz signal, possibly only 3/4 will pass through. Essentially if you set the sub's X-over to 80 and the Amp, you'll wind up with a frequency dip around 80Hz which could be quite noticeable. Setting something like 120Hz on the sub put's the attenuation out of band, so that you get the proper frequency response.

Sorry if that seems confusing, I can probably explain better if it doesn't make much sense (it'll just take me a lot more time to type out!)

 

[Droogie 2001]

Thanks for the replies guys.
So Evilmudge are you saying that setting the Sub's crossover to 120hz is the preferable option?

Also I was thinking that the sub's volume dial should I guess be carefully altered to the preferred level.
I suppose mine is set to a 2 o'clock position.

 

[bob007]

Originally posted by mraggett
setting the Sub's crossover to 120hz is the preferable option?

Also I was thinking that the sub's volume dial should I guess be carefully altered to the preferred level.
I suppose mine is set to a 2 o'clock position.

From what I gather from reading other members bass management settings when using Kef eggs, the recommended xover setting on the amp should be around 100Hz and the xover set to max on the sub.

Setting the volume on the sub: The easiest way is to set the subs master volume at about 12'oclock/2o'clock, then you can adjust it either way via the amps bass management.

EvilMudge,

Thanks for the info.

 

[Reiner]

Depending on the application the cross-over in the sub is redundant, specifically when used in an AV setup and connected via line level. Thus it should be set to MAX and the rest is taken care of by the AV amp/receiver.

Note: do not set the sub lower than 120Hz as else you cut of the LFE (which goes from 0-120Hz). In fact a bit more is preferred because as mentioned it's not a straight cut but rather a slope.
But to make things easy just set it to max as mentioned above, this will do no harm ...

 

[Lowrider]

In your setup, and mine, the sub´s xover is indeed redundant, I switch it off, if you cannot, just leave it at max... 120hz is correct for the eggs, IMHO...