Rotel problem - RSX 1067 / RB 1080 bass missing?

[lars]

Hello All,

I have an RSX 1067 and an RB 1080 that I use bi-wired to a pair of Infinity kappa 9.2i towers (2 channel only).

If I use the 1080 to power the bass I get almost nothing. If I use the 1067 for the bass it's good - but I would much rather use the lower power 1067 for the lighter need mids and tweets and keep the 1080 for the much higher need 4x12" drivers.

I've checked phase and I don't see any way to modify what's coming out of the preamp outs in the 1067 menu.

I hooked up the 1080 to another receiver to test with and it has plenty of power, so the problem seems to be the 1067 preamp outs.

Any suggestions would be welcome -

[Mig17]

I have one Rotel 1068 "processor" and I think It sound worse than my old Denon 1602
what a painful memory
I changed to Anthem AVM D1 to pair with Rotel amps
and the sound was so exiting with both music and movies

Denon 2900/Anthem D1/Rotel amps/Jmlabs Cobalts

[lars]

I have one Rotel 1068 "processor" and I think It sound worse than my old Denon 1602
what a painful memory
I changed to Anthem AVM D1 to pair with Rotel amps
and the sound was so exiting with both music and movies

Denon 2900/Anthem D1/Rotel amps/Jmlabs Cobalts

Okay, thanks for your response Mig17.

Unfortunately I'm a bit let down with Rotel. Between the 1067 with preamp out problems and the 1050 DVD player that has really bad video output...I paid way too much to have all this trouble.

Would have put them in for warantee repair during the 2 year period but didn't want to lose them for 2 months (as I lost the 1067 for two months after a firmware 'upgrade'.

So now I've got three peices of Rotel kit I paid a lot for and feel that I would have been better off with, all out of warantee.

[Mig17]

when my 1068 was sounding bad I thought that it might be not broken in yet
but after 2 month the sound had no improvement , the sound was so sharp

[Mig17]

Otherwise , I keep my Rotel amps they are very reliable and different and wonderful

[Kevin D]

Have you hooked jus tthe RB1080 up to both high and low posts? I'm wondering if the gain is mis-matched enough that the high's get loud sooner then the lows.

Kevin D.

[lars]

Have you hooked jus tthe RB1080 up to both high and low posts? I'm wondering if the gain is mis-matched enough that the high's get loud sooner then the lows.

Kevin D.

Hello Kevin,

Happy to try that but if I have nothing hooked up to the 1067 speaker outs do I risk damaging it?

Thanks,
Lars

[Kevin D]

Not at all..

Kevin D.

[lars]

Have you hooked jus tthe RB1080 up to both high and low posts? I'm wondering if the gain is mis-matched enough that the high's get loud sooner then the lows.

Kevin D.

Hello Keven,

Disconnected the 1067 speaker out connections and replaced the bridges to un-biwire, if you will, the speakers so that they're driven only by the RB1080.

Result: much less volume, in line with the 'missing bass' of using the 1080s just for the bass. Strangely I also noticed very little midrange and up from the left channel (this didn't happen when bi-wired). [Edit] The low volume on the midrange and up was poor cabling on my part. The sound overall is very flat, still low volume in line with the 'missing bass'.

Last time I was troubleshooting this I used a NAD preamp with the 1080, no 1067 in line at all, and the sound was much better, not flat at all.

Seems to me that it's really a problem with the pre outs on the 1067.

I'll start another thread on the video quality problems I have with the 1050 -

Thanks again,
Lars

[WI Rotel]

Have you hooked jus tthe RB1080 up to both high and low posts? I'm wondering if the gain is mis-matched enough that the high's get loud sooner then the lows.

Kevin D.

This is the problem without a doubt. Simply the foibles of a biwiring scheme. Simply connect it the "right" way and thats it. You will solve a problem the you shouldn't have to begin with. NO one has ever proved that biwiring is of any benefit except in their own minds. If you wish to Bi "something" buy another amp and bi-amp. Bi amping has been proven to improve sound though the reasons, other than dramatically increasing the available power to the speaker as a whole thus keeping each amp comfortable, are murky at best. In a "perfect world" every driver in a speaker should benefit from its own dedicated amplifier.

[lars]

This is the problem without a doubt. Simply the foibles of a biwiring scheme. Simply connect it the "right" way and thats it. You will solve a problem the you shouldn't have to begin with. NO one has ever proved that biwiring is of any benefit except in their own minds. If you wish to Bi "something" buy another amp and bi-amp. Bi amping has been proven to improve sound though the reasons, other than dramatically increasing the available power to the speaker as a whole thus keeping each amp comfortable, are murky at best. In a "perfect world" every driver in a speaker should benefit from its own dedicated amplifier.

Apologies I've used the wrong terminology. I am bi-amping, using the 1067 to drive the bass (would prefer to use the 1080 but then I get no bass due to the volume problem) and the 1080 to drive the mids and tweets.

So a summary:
1067 alone: good sound but need more power
1080 alone using pre-amp outs of the 1067: flat sound, poor volume
1080 alone using pre-amp outs of a NAD: good sound, good volume
1067 driving mids & highs, 1080 driving lows: mids and highs good, bass low volume (as in almost non-existant; in line with using the 1080 alone with the 1067 pre-amp outs)
1080 driving mids & highs, 1067 driving lows: good but amps cut out during a good movie scene

I also have a problem with the volume knob when turning down the volume sometimes turns up the volume but that's lower on my list of priorities (good sound, then the video problem with the 1050 more important)

Thanks again for your help,
Lars

[WI Rotel]

Apologies I've used the wrong terminology. I am bi-amping, using the 1067 to drive the bass (would prefer to use the 1080 but then I get no bass due to the volume problem) and the 1080 to drive the mids and tweets.

So a summary:
1067 alone: good sound but need more power
1080 alone using pre-amp outs of the 1067: flat sound, poor volume
1080 alone using pre-amp outs of a NAD: good sound, good volume
1067 driving mids & highs, 1080 driving lows: mids and highs good, bass low volume (as in almost non-existant; in line with using the 1080 alone with the 1067 pre-amp outs)
1080 driving mids & highs, 1067 driving lows: good but amps cut out during a good movie scene

I also have a problem with the volume knob when turning down the volume sometimes turns up the volume but that's lower on my list of priorities (good sound, then the video problem with the 1050 more important)

Thanks again for your help,
Lars

Got it. Thus the problem, different amps with different input sensitivity/gain driving the same speaker. If you check the rotel website the 1067 is 1 volt the 1080 is 1.5 (a huge difference). The amps used in bi amping should be the same. Forget the 1067 and simply use it as a pre. Better yet plop another 1080 into the mix and biamp with 2 1080's :E :T Cheers

[lars]

Got it. Thus the problem, different amps with different input sensitivity/gain driving the same speaker. If you check the rotel website the 1067 is 1 volt the 1080 is 1.5 (a huge difference). The amps used in bi amping should be the same. Forget the 1067 and simply use it as a pre. Better yet plop another 1080 into the mix and biamp with 2 1080's :E :T Cheers

Thanks Kevin

Question though - if I use the 1067 as a pre with only the 1080 driving it, I should have more power than the 1067 alone and sound that is at least as good quality should I not?

But what I get is considerably lower volume and really flat boring sound with that configuration (against using just the NAD pre with the 1080).

Thanks gain

[WI Rotel]

Thanks Kevin

Question though - if I use the 1067 as a pre with only the 1080 driving it, I should have more power than the 1067 alone and sound that is at least as good quality should I not?

But what I get is considerably lower volume and really flat boring sound with that configuration (against using just the NAD pre with the 1080).

Thanks gain

Oui, however, if the signal from the 1067 is too low (doubtful) you might not drive the 1080 to full capacity. Lars I suspect that our problem of not enough bass stems from the jumper configuration. The correct way to do it is to use your 1067 external amp connection to connect it to your 1080, and connect the speakers to the 1080 with a single cable. The jumper on your speakers should be engaged (pos to pos, neg to neg). Another possibility for lack of bass could be that when you did the bi amp "test" you got the polarity reversed and the drivers were thus out of phase.... Good luck and let us know :T

[Kevin D]

Thanks Kevin

Question though - if I use the 1067 as a pre with only the 1080 driving it, I should have more power than the 1067 alone and sound that is at least as good quality should I not?

But what I get is considerably lower volume and really flat boring sound with that configuration (against using just the NAD pre with the 1080).

Thanks gain

Since it seems like it's a gain problem, with the 1080 having a lower gain the the 1067, you can't compare the sound at the same volume number.

IE, don't compare the 1080 vs the 1067 both at volume 50. You will have to listen to the 1067 alone, then listen to the 1080 (increasing the volume until it's at the same SPL output as the 1067 alone). If you do that and still find the 1080 lacking, then there's a problem somewhere.

I would suggest picking up an SPL meter so you can balance all the levels though. If you do keep the 1080 for the fronts, I would imagine you would need to increase the front levels and decrease the center/surround levels to balance everything out.

A nice benefit to using just the 1080 is you can reassign the front 1067 channels to be zone 2 speakers.

Kevin D.

[lars]

I would suggest picking up an SPL meter so you can balance all the levels though. If you do keep the 1080 for the fronts, I would imagine you would need to increase the front levels and decrease the center/surround levels to balance everything out.

Kevin D.

Thanks Kevin - just a last question on this...how do you balance levels? I don't see any way to increase/decrease the output from the 1067 for the pre-amp outs.

Thanks again,
Lars

[Kevin D]

It's under the SPEAKER menu option. Same one you use to adjust the amplfied speaker level. So no, you can't increase the pre-out levels while keeping the amplified level the same (for the same channel).

Kevin D.