Denon 3805 crossover problem

[pbarach1]

Even though all speakers connected to my Denon 3805 are set to SMALL, subwoofer is set to ON, and the crossover point is set to 80 Hz, I'm noticing that my front speakers (Kef Q7's) are trying to play tones well below 80 Hz. I found this out when using the Rives Audio Test CD (which I won on this forum, thanks to Audioholics and Rives!). Tones as low as the 20-40 Hz range are coming out of the front speakers' woofers. I can feel these drivers moving strongly when I touch them as these low-frequency tones are being played. I also played back these tones through the analog outputs of my CD player, which has a fixed crossover point of 100 Hz, and the woofers in my main speakers are still trying to play these tones. As I understand the 3805 manual, when the subwoofer is set to ON and speakers are set to SMALL, frequencies below the crossover point should be played only through the subwoofer. What's wrong??

 

[mtrycrafts]

Even though all speakers connected to my Denon 3805 are set to SMALL, subwoofer is set to ON, and the crossover point is set to 80 Hz, I'm noticing that my front speakers (Kef Q7's) are trying to play tones well below 80 Hz. I found this out when using the Rives Audio Test CD (which I won on this forum, thanks to Audioholics and Rives!). Tones as low as the 20-40 Hz range are coming out of the front speakers' woofers. I can feel these drivers moving strongly when I touch them as these low-frequency tones are being played. I also played back these tones through the analog outputs of my CD player, which has a fixed crossover point of 100 Hz, and the woofers in my main speakers are still trying to play these tones. As I understand the 3805 manual, when the subwoofer is set to ON and speakers are set to SMALL, frequencies below the crossover point should be played only through the subwoofer. What's wrong??

Since you have that test disc, you may also want to do a tes, if you have an SPL meter.
See how much the frequency drops below 80Hz, how fast?
Don't forget, the crossover network is not perfect in that there is no 79Hz frequency being passed Or any below 80Hz. Crossovers are rated by slopes, 24dB drop off per octave, meaning that at 40 Hz, you should have 24dB spl less in those small speakers. That, is a steep crossover. Lots are much less, 18 dB, 12 dB or less.

 

[pbarach1]

crossover slope...

I talked to Denon tech support and they confirmed what you said about the crossover being sloped rather than sharply cut off. I forgot about that

 

[brendy]

Are you sure it is set up to send all bass to the sub only,not sub + L & R ?

 

[pbarach1]

Are you sure it is set up to send all bass to the sub only,not sub + L & R ?

Yes... When the 3805 sets the speakers to SMALL, then everything below the chosen crossover point goes ONLY to the subs. If the speakers are set to LARGE, then and only then does the 3805 give you the choice of sending low frequencies to either the sub OR sub+L+R.

 

[mtrycrafts]

I talked to Denon tech support and they confirmed what you said about the crossover being sloped rather than sharply cut off. I forgot about that

Did the tech by chance tell you the slope rate, how many dB/octave?

 

[pbarach1]

He wasn't sure

Did the tech by chance tell you the slope rate, how many dB/octave?

He said he wasn't sure if the slope was 24 dB down and 12 up, or the opposite. I didn't query further, since that level of detail isn't of practical value to me.

 

[MDS]

He said he wasn't sure if the slope was 24 dB down and 12 up, or the opposite. I didn't query further, since that level of detail isn't of practical value to me.

24 dB/octave low pass (4th order) and 12 dB/octave high pass (2nd order) is pretty standard and would be my guess.

 

[pbarach1]

24 dB/octave low pass (4th order) and 12 dB/octave high pass (2nd order) is pretty standard and would be my guess.

What do 2nd order and 4th order mean?

 

[MDS]

Each order is 6 dB per octave which means the signal is attenuated (reduced) 6 dB for every octave. So, 1st order is 6 dB/octave, 2nd order is 12 dB/octave, 3rd order is 18 dB/octave and 4th order is 24 dB/octave.

The typical low pass (let's the 'lows pass') to the sub is 4th order. If your xover is set to 80 Hz and is 4th order, 40 Hz signals (one octave below the xover) will be attenuated by 24 dB. The 'order' of the xover is what people are talking about when they say a xover has a slope.

 

[ashipps]

Denon AVR-3805 (Manual-EQ Fails to Function)

While you are talking about rolloff I have experienced a different EQ problem with my 3805. I have made adjustments to the manual EQ; however the sound remains the same. The manual EQ is not-activated. I have tried various settings (e.g. All/Assign and Off/Flat/Front/Manual) settings. None of these settings seems to activate the EQ. I must be missing something! Does anyone have any tips on activating the manual EQ on a Denon AVR-3805?

 

[pbarach1]

it should be easy

On your remote, next to the SYS SETUP button, is the ROOM EQ button; just press it repeatedly until the dial on the 3805 reads "Room EQ: Manual" (this will also show up on screen if your TV is on). You can also flip open the covered collection of buttons on the front of the 3805 unit itself, and you'll see a ROOM EQ button there as well. Either button will change the EQ adjustment to OFF-NORMAL-FLAT-FRONT-MANUAL. If it doesn't change what you hear, then either your EQ adjustments are too subtle to make a difference that you can hear, or else your hearing isn't as good as you think.