RSP1068 bass management woes

**csuzor** · 01 December 2005, 06:59 Thursday

Actually, it is designed that way, page 35 of the manual, "large front speakers small center and a sub"... If your system is symetrical, this mono bass input into L/R will seem to come from the center anyway.

If you dont like that, set the fronts to small, and cross-over the fronts at 40Hz (reasonable anyway for most floorstanders) and the center at 80Hz. That should prevent center bass being redirected to the fronts.

Otherwise, why not leave the center to large anyway, the bass it cannot reproduce will be carried by the LFE anyway (unless it is very small).

**Big Gav** · 01 December 2005, 07:12 Thursday

Thanks for that Csuzor,
I guess my experience with other amplifiers is that if you state your centre speaker is small and you have a sub then the bass that would have occured in the centre is routed to the sub rather than the mains.
I think I will just live with everything large - my mains can do 120db @ 20Hz (tested 3m from speakers with sound metre) so I would not want their bass abilities to go awol

**csuzor** · 01 December 2005, 07:34 Thursday

Wow, that's very impressive for the fronts. How much power did you have to pump in??

But, it seems the Celestion A3 spec is
Frequency response (+- 2dB) 36 Hz - 20 kHz
Recommended amplifiers 30 - 300 W
Sensitivity (SPL @ 1m for 2.83V) 90 dB
Nominal impedance 4 ohm
Power rating 200 W
Height x Width x Depth mm 1130 x 280 x 400
Weight 46 kg - 101 lb

so to get a measurable response at 20Hz you must push the higher frequencies at much higher volumes. Now, with those speakers, you could avoid using a sub altogether, but if you do have a sub, crossing at 40Hz would probably give you the flattest frequency response. Like all big floorstanders.

**Big Gav** · 01 December 2005, 08:52 Thursday

I got the measurements using a test disc with tones that go down to 10Hz. By the way I got 115db at 15Hz before I got to scared to go higher. At the time I got those measurements I was using a NAD208 THX to power them. All six 8" drivers were pulsing in an incredible way and my chest and other internals were talking to me.
When I bought the speakers the reviews from Audio magazine in the states and a number of british mags all commented on the speakers remarkable dynamic performance. I wanted a speaker to play loud without compression across a broad frequency range, sound neutral and good with music. I used to work for Len Wallis Audio (Australia's largest specialist hi-fi store) and have heard the best (ie Focal JM lab grand utopia Be's driven by the best halcro amps etc and will admit my speakers are not in their league but I still back them in dynamic terms at least against anything I have heard under $25,000 Australian. When I get my picture up you will see what they look like. As someone who writes for a couple of hi-fi magazines here they are still a great tool. tomorrow I can't wait to try out War of the worlds on the system. I had better warn the neighbors first though.

cheers, Big Gav.

**aud19** · 01 December 2005, 13:48 Thursday

Regardless of that impressive ability I agree, run the mains as small with a 40Hz crossover. It's not a brickwall so you'll still get some below 40Hz material going to the mains anyways. Besides you can still listen to them full range for music

**Big Gav** · 01 December 2005, 17:48 Thursday

G'day aud19,
I was just wondering how steep those filters would be and how much of a 25Hz signal would get through?
Cheers ;x)

**ekkoville** · 01 December 2005, 19:38 Thursday

I must be missing something here....why set the mains to small? I guess everything should then be set to small and then adjust the crossover accordingly.

**pbarata** · 01 December 2005, 19:55 Thursday

Originally posted by ekkoville

I must be missing something here....why set the mains to small? I guess everything should then be set to small and then adjust the crossover accordingly.

After trying many configurations I agree that, even with full range speakers like mine, the best is to set them all to small, and choose the crossover to 60 Hz, redirecting all below frequencies to a subwoofer. The overall response for movies will be “faster” as your speakers will not try to reproduce those very low frequencies.

**ekkoville** · 01 December 2005, 21:17 Thursday

I think that makes sense....but what is the difference in setting Small vs. Large but using the same crossover? What does the processor do differently when the crossover is the same but you change the selection between Small and Large?

**aud19** · 01 December 2005, 21:19 Thursday

"Large" disables the crossover for that speaker group

**ekkoville** · 01 December 2005, 22:38 Thursday

AHHHHH, now me undastand Grasshoppa!!

**Big Gav** · 02 December 2005, 00:18 Friday

I guess I will just have to decide if I want a leaner bass response without any deep bass contributions from my mains or go for that slightly more even bass coverage that I get from having multiple speakers doing the low stuff. Fortunately summing the deep bass into the sub will not upset my DD18 but I feel a bit sad robbing myself of a bit of extra oomph when I went and bought speakers that could do it. At least I know it is not a glitch then. thanks guys.

**pbarata** · 02 December 2005, 08:40 Friday

Originally posted by Big Gav

I guess I will just have to decide if I want a leaner bass response without any deep bass contributions from my mains or go for that slightly more even bass coverage that I get from having multiple speakers doing the low stuff. Fortunately summing the deep bass into the sub will not upset my DD18 but I feel a bit sad robbing myself of a bit of extra oomph when I went and bought speakers that could do it. At least I know it is not a glitch then. thanks guys.

I didn’t mean to get rid of all your bass content from mains speakers. Even with the same brand, probably you will have different low frequencies response from your speakers. Most likely your front floor stands will give as low as 35 Hz , your surrounds will cut below 45 Hz and your central about 60 Hz, unless you have all of them exactly equal.

The ideal would be to have a crossover for each pair, redirecting exactly what your front/rear speakers will not be able to reproduce, allowing that extra bass to be played by the subwoofer.

In my case with the RSP-1066, with only one crossover for everything, I get the best results with 60 Hz value. Once a while, I change the front speakers from small to large, especially for music DVD’s, where stereo still play a major role.

**aud19** · 02 December 2005, 13:49 Friday

Yup I too have my 1066 set at a 60HZ crossover for my speakers that play down to the 30's (C9's) and 40's(C5's and CC3) for movies but run them all full range for music with great results :T

RSP1068 bass management woes

RSP1068 bass management woes

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