crossover frequency and cut off for RF15 system w/ RW12 sub

[om13934]

I just bought a pair of RF15's with RC25, RS25's and an RW12 sub. I'm having trouble finding a good combination with the cutoff frequncy for my RF15's and the crossover on the sub. I find that when I'm watching movies with some mid to low frequencies, my RF15's are taking too much, and the sub, not enough. I've got my receiver(Denon avr1804) set to an 80hz cut off for my RF15's and the sub is up to just above that for the crossover. The RF15's are just distorting the lower frequencies in their range a little. I really don't want the sub to be handling anything much above 80hz. Any suggestions?

[dougdrake]

Are you using the sub-out on the Denon? If so, then you want to bypass the crossover in the sub itself by either pressing a bypass button (if there is one) or by setting the crossover as high as it will go. You don't want to "double filter." That might help clean things up a bit.

Does your Denon has adjustable crossover settings? If so, turn them up a bit for the mains if you think they are taking too much. I find it difficult to believe that they are distorting on anything if you have the x-over set at 80hz, but who knows...

If you don't have adjustable x-over in the Denon, the only other way to affect the crossover is to connect your main speaker outputs to the sub and then your speakers to the sub and use the sub's x-over which is infinitely variable within its range.

You can also affect their sound by their placement - subs in corners sound louder and you can move the speakers away from the walls some to diminish the low end response.

dd

[om13934]

Thanks, the denon does have adjustable crossover settings, but like you, I found it difficult to believe that the RF15's were distorting the low end at 80hz since their response goes as low as 46hz. It is just at high volume levels that I think the woofers on the RF15's are trying to handle more than they should. I'll play with it a little more.

[Darren]

May want to check your receiver set up. Within the Base management, you may have 3 choices on the subwoofer: on, off and Max (or both). Under the last option, low signals are sent to both the sub AND your mains. If that's how you are set up, you are getting signals below the cross over to the mains, which may be causing the problem. If that is your set up, try selecting "yes".

Also, if you have your speakers set as "large", the cross over may not be working at all. In most cases (that I've seen), the cross-over only diverts the low signal from the "small" speakers - "large" speakers continue to get the full signal.

[om13934]

Thanks Darren, that's exactly what it was. My rf15s were set to large and taking a little too much low end. Am I going to experience any loss in performance by changing that setting to small. Should the sub be able to handle everything cleanly up to 80hz? Thanks

[Darren]

Performance should be better - by not taxing your mains, they should perform better on the mids and highs. I've not familiar with the RW-12, but I would be shocked if it couldn't handled up to 80hz - may even want to try 100 hz (I understand 100 hz is very common in home theater unless you have very large mains when 80 - or even 60 - is more common).

I'm still playing with mine as well. It hurt to call my RF-7's "small" in the set up, but at 80hz it's sounding pretty good to me (just made this change so not much testing yet).

[fabulousfrankie]

Set all speakers to small and send everything to the sub, it will free up all speakers of the bass duties and they'll play cleaner. Receiver manufacturers really should have used words other than large or small for the setting, in 99% of rooms I think it's best to set all speakers to small and have a sub handle all the lows, that's what I do with my very bass capable KLF20's and it sounds better than them being set to large. The RW12 will have no poblem playing up to 80hz.

Also don't forget to recalibrate the levels of each speaker after you do this.

[om13934]

Thanks for all the info. The sub is up to about 85 hz now, and the rf15's set to small.

". It hurt to call my RF-7's "small" in the set up, but at 80hz it's sounding pretty good to me "

I understand what you mean Darren. (AND I ONLY HAVE RF15's!) We'll give it a few weeks of listening to see how performance matches.

[fabulousfrankie]

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On 1/29/2004 12:56:38 PM om13934 wrote:

Thanks for all the info. The sub is up to about 85 hz now, and the rf15's set to small.

". It hurt to call my RF-7's "small" in the set up, but at 80hz it's sounding pretty good to me "

I understand what you mean Darren. (AND I ONLY HAVE RF15's!) We'll give it a few weeks of listening to see how performance matches.

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You need to turn the crossover on the sub to it's highest position. You already have an 80Hz crossover in the Denon and you do not want your Klipsch's crossover interfering with that, it will cause more problems.

[yromj]

You definitely want to set the sub's cross-over to the maximum position. Secondly, I like the idea of setting the crossover one octave above the bottom cutoff of the mains. Therefore since the RF-15s go to 46Hz, a 92Hz crossp-over is what I would shoot for. Of course your receiver probably doesn't have that setting, so 100 would be very close. This compensates for the fact that the crossover is not a "wall", but a slope. Usually the slope is 18-24dB/octave. This way the transition between the mains and the sub is more subtle in cross-over range.

John

[Darren]

"You need to turn the crossover on the sub to it's highest position."

and

"You definitely want to set the sub's cross-over to the maximum position".

That's interesting - when I set my cross-over in my processor to 80hz, I assumed setting the cross-over on the sub to 80hz also made sense. When I turned the sub crossover up to max, it either picked up more range, or more likely more volume (I didn't expect that). I left it as max, but thought I just had screwed-up ears! Sounds like I accidentally did it "right"!

"Secondly, I like the idea of setting the crossover one octave above the bottom cutoff of the mains. Therefore since the RF-15s go to 46Hz, a 92Hz crossp-over is what I would shoot for"

I think that would put the cross-over for my 7's at 60hz? I'll give that a shot - thanks!

[yromj]

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On 1/30/2004 3:32:20 AM Darren wrote:

When I turned the sub crossover up to max, it either picked up more range, or more likely more volume (I didn't expect that).

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Actually you gained a little of both. Remember, above the cross-over frequency (for a sub), the volume drops off linearly, for example 18dB/octave. Therefore, just picking numbers out of the air here, if the sub is putting out 90dB @ 80Hz (and 80Hz is the cross-over w/ an 18dB/octave slope), then it's putting out 72dB @ 160Hz. When I first got into this stuff, I thought the cross-over was a brick wall. If I set the cross-over @ 80Hz, then that's where the sub stopped producing sound.

The cross-over for the mains is doing the same thing coming down. If they're producing 90dB @ 80Hz then they're producing 72dB @ 40Hz, assuming the same conditions as before.

Try setting the cross-over to 60Hz for your 7s and let us know what happens.

John

[MrMcGoo]

It took more than a year, but I have decided to run my RF-7s as small and to use 80 Hz as the crossover. I bypass the sub's crossover. The sound is cleaner and clearer all around.

It is best to totally bypass the sub's crossover when possible, if your receiver's or processor's corssover is being used. If that is not possible, then the sub's crossover must be set to its highest frequency as others have pointed out.

If both crossovers are set to 80, for example, the slope of the crossovers is "cascaded" and there will be a "hole" in the bass frequencies due to the combined slope of the crossovers.

Bill