Subwoofer crossover


Is there any difference between the crossover adjustments made in the receiver and those made in the subwoofer?

John A.
The subwoofer setting is the highest frequency for a low-pass filter. It says "ignore all stuff coming in above __Hz".

The receiver setting is a variable crossover setting , it says "Send stuff above __Hz to the main channels; stuff below __Hz to the subwoofer"

In perfect world you will set them to the same value of Hz, and lose nothing. In the real world you might set the sub to a slightly higher value than the reciever, to make sure nothing falls between the gap. Then, if the receiver and sub are true to their word, you will not hear the overlap frequencies twice.

If no-one minds:- Hz is a unit of frequency named after Mr Hertz; one Hertz is one compete wave per second. Sound waves of air pressure, and is audible between about 20 Hz (really deep stuff, almost just vibration) and say 10,000-12,000 Hz (young, fit, human; it sounds like a high-pitched whistle). Your own high frequency cut-off declines with age.

Bookshelf-type loudspeakers go from about 80 Hz (it varies from speaker to speaker) up to the top, usually 20,000 Hz (equals 20 kHz), beyond what you can hear. Big, floorstanding loudspeakers might start, instead, at about 40 Hz (that also varies), low enough for most music, and also go to the top.

A subwoofer should extend the lowest sounds further downwards, whether you start with the low cut-off of bookshelves or floor-standers. It should do no more than that. It should be able to take you down below the linti of the other speakers, to a lower limit of 25-30 Hz, or evenlower. The upper limit of the sub (that is the setting you choose) is still very low bass sound.

Dolby and DTS claim to give 20 Hz to 120 Hz on the ".1" channel, though there may be deep sounds down to 20 Hz on the main channels, too, especially with DTS. The receiver should sent those to the sub if the speakers are too small to handle them. The crossover of the receiver is the frequency at which it does that.

Thanks a lot, John.
I have a question: if I connect a subwoofer like...Yamaha YST-205 to my receiver, Yamaha RX-V1300; then the continuously variable setting of the subwoofer can supply the lack of the adjustment of my receiver? (fixed cut at 90 Hz)

John A.
You are welcome, Alberto. If I understand, the receiver has a fixed cut at 90 Hz. Set the sub filter to that. Then nothing should be lost or doubled up, provided the receiver is not throwing away the 90-120 Hz range in the ".1." channel, but giving it to the main channels, instead. I don't know the Yamaha, though. A receiver should also let you use all channels full-range if you have the speakers to match and that is what you choose. Then there is no receiver cut at all. In that case, set the sub to 120 Hz. Then the sub gets all that Dolby and DTS intended it to get.

Then, can I do the following?
Connect the subwoofer through the speaker line level and set the filter with the subwoofer control.

John A.
"Speaker line level". If you mean connecting the subwoofer to the Left and Right speaker outlets on the receiver, then the L and R speakers to the "speakers out" on the sub, then "Yes". But then there should be no cut in the receiver. The receiver cut only applies to decide which frequencies are directed to the "line level", ".1", "subwoofer out" or "LFE" channel (they all mean the same thing; it will be one RCA plug and a co-axial cable). In the latter case, the subwoofer is the end of the line, and takes what it is given.

Yes, sorry. It´s Speaker level input.
Then, if I understood, I must do that. By-pass the LFE out of the receiver (90 Hz Cut) and use the filter of the subwoofer.
Thank you very much, John

John A.
Yes, I think that is right.
"Audiophile" subwoofer manufacturers like REL recommend that way of connecting a sub, anyway. An advantage is that you also get the benefit of the subwoofer in stereo: it gives the lower frequencies your main speakers cannot reach.
If this is helpful, I am pleased.

Yes, it is. Thank you John A.

If your receiver has a adjustable crossover, is it best to match the sub crossover with it (so your double filtering) or is it best to bypass the receiver and use only the sub's crossover or just use the receiver's crossover and set the sub's to the highest setting that way your sure to get everything ?

This is assuming main speakers are set to small and for a home theater setup...
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