Yamaha RX-V685 with Bose Acoustimass 10 III problems

stupidearthling

Novice Member
I have the RX-V685 with a fairly old Bose Acoustimass 10 III. On the whole it is great.

When it is working, it seems to sound fine with plenty of bass - With or without the blue connector plugged in - which I thought was the bass box, thus leading me to the conclusion that I have wired it up incorrectly or my Yamaha has never been spitting out the subbass.

However, every once in a while the bass cuts out completely. I'm not sure if this is the Amp or the Acoustimass failing.

To fix it, I remove the blue connector plugged into the subbass output and short the positive pin to earth. Clearly something amiss somewhere.

Does anyone know if the Acoustimass bass box should get the bass from the blue connection, or does it draw the bass from the other speaker channels.



IMG_20211207_175045__01.jpeg
 

Jay53

Well-known Member
Had a look at the quick install guide and regarding the blue connector I would say it depends on how you have set up your avr

You have an active i.e powered sub. Some Bose systems (like the one I have are passive and don't use the LFE blue output at all)

However, ss all the cube speakers run through the unit containing the sub(s) it's filtering L, C, R, LS & RS outputs for low Freq sending them to the sub and then passing on the rest to the cubes. In addition it will also take the LFE feed from the blue connector.

It will only do this is you have the avr set to 5 speakers + LFE. If you have set it to just 5 speakers the blue LFE connector will not output any signal as anything that would have been sent to the LFE out would be redirected to the Left and right front speakers.

As to the cutting out its more likely a power issue to the sub within the unit so I would get that checked out for a loose connection.

In terms of setting these Bose systems up as they have their own filtering you should set ALL speakers to Large. That way the Bose system will filter as it requires rather than trying to get the avr to do it.
 
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stupidearthling

Novice Member
Had a look at the quick install guide and regarding the blue connector I would say it depends on how you have set up your avr

You have an active i.e powered sub. Some Bose systems (like the one I have are passive and don't use the LFE blue output at all)

However, ss all the cube speakers run through the unit containing the sub(s) it's filtering L, C, R, LS & RS outputs for low Freq sending them to the sub and then passing on the rest to the cubes. In addition it will also take the LFE feed from the blue connector.

It will only do this is you have the avr set to 5 speakers + LFE. If you have set it to just 5 speakers the blue LFE connector will not output any signal as anything that would have been sent to the LFE out would be redirected to the Left and right front speakers.

As to the cutting out its more likely a power issue to the sub within the unit so I would get that checked out for a loose connection.

In terms of setting these Bose systems up as they have their own filtering you should set ALL speakers to Large. That way the Bose system will filter as it requires rather than trying to get the avr to do it.
Thanks for the tips - I had the speaker set to small, so that's now fixed.
Also good to know that the reguar bass is coming through on the speaker outputs - Obvious now I think about it. I found a subwoofer test on youtube and it does seems the LFE is working, although I'd imagined the difference to be more.

Thanks again for your help. Appreciated!
 
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stupidearthling

Novice Member
I'm guessing the cutting out is going to be a component failing.
I've sacraficed the LFT for now and left the blue cable disconnected. When the bass cuts out, simply tapping the Blue LFE connectors pole with my finger is enough to jumpstart the bass back into action. Not sure if that's indicitive of any particular fault.
 

Jay53

Well-known Member
It sounds like the LFE connector on the Acoustimass module is shorting out and tapping it stops the short for a while? What happens if you totally remove the blue ended cable so it's not connected at either end or is it fixed at the module end?
 

dante01

Distinguished Member
The cable going from the AV receiver's sub pre out to the sub, how is it terminated at the sub end? If simply an RCA terminated cable at both ends then buy a new RCA terminated sub cable or replace it with another RCA terminated cable.

The intermittant output from the sub and the fact that you toughing the connection on the cable rectifying it suggests the cable is faulty?

As to the AV receiver's configutations. THe speakers will need to be all set as SMALL and the associated crossover need to be set no lower than the rated frequency handling capabilities of those speakers. This results in frequencies that your speakers are unable to portray being redirected out to the sub and away from those speakers. The speakers in question will not by any meand qualify as being LARGE. In the presence of an active sub in a setup, the LFE channel is always sent to that sub. Again, your passive speakers will not be able to portray this channel correctly.



An active sub should be connected to an AV receiver's sub pre out and the passive speakers to the AV receiver's speaker terminals. You should not be connecting the sub to the AV receiver's passive speaker terminals and then passing the signal through the sub and out to the passive speakers. THe AV receiver has no ability to manage the bass in such scenarios. The only connection to the active sub should be from the AV receiver's sub pre out and the passive speakers should be connected directly to the AV receiver's speaker terminals.



I'd also suggest not using Bose Acoustimass speaker packages. They are useless and cause more issues than they are worth.
 

dante01

Distinguished Member
My investigations indicate that the RCA cable from the AV receiver's sub pre out goes to a custom connector on the sub:


by default 2021-12-08 at 08.59.50.png



This makes it difficult to replace the associated wiring or cable.


I'd suggest the bBoss package not ideal and a more conventional alternative arrangement be looked at.
 

Jay53

Well-known Member
The cable going from the AV receiver's sub pre out to the sub, how is it terminated at the sub end? If simply an RCA terminated cable at both ends then buy a new RCA terminated sub cable or replace it with another RCA terminated cable.

The intermittant output from the sub and the fact that you toughing the connection on the cable rectifying it suggests the cable is faulty?

As to the AV receiver's configutations. THe speakers will need to be all set as SMALL and the associated crossover need to be set no lower than the rated frequency handling capabilities of those speakers. This results in frequencies that your speakers are unable to portray being redirected out to the sub and away from those speakers. The speakers in question will not by any meand qualify as being LARGE. In the presence of an active sub in a setup, the LFE channel is always sent to that sub. Again, your passive speakers will not be able to portray this channel correctly.



An active sub should be connected to an AV receiver's sub pre out and the passive speakers to the AV receiver's speaker terminals. You should not be connecting the sub to the AV receiver's passive speaker terminals and then passing the signal through the sub and out to the passive speakers. THe AV receiver has no ability to manage the bass in such scenarios. The only connection to the active sub should be from the AV receiver's sub pre out and the passive speakers should be connected directly to the AV receiver's speaker terminals.



I'd also suggest not using Bose Acoustimass speaker packages. They are useless and cause more issues than they are worth.

In a normal sub/speaker package I would agree but with bose arrangement that includes active specifically tailored filtering within the Acoustimass module that ALL speakers run through you need to set ALL speakers to large.
 

dante01

Distinguished Member
In a normal sub/speaker package I would agree but with bose arrangement that includes active specifically tailored filtering within the Acoustimass module that ALL speakers run through you need to set ALL speakers to large.


Yes, I realise that after looking at the manual and realising that the package doesn't dascilitate connecting the passive speakers directly to the AV receiver, not without cutting the termibnations on the enfs of the cables for the speakers anyway. You could actually do this and then connect those speakers directly to an AV receiver without to connect them to the sub.


I think the issue here is the sub pre out connection, but if thr OP where to set the sub setting to NONE within the AV receiver's speaker configurations then he's negate the need for a connection from the sub pre out to the sub because a discrete LFE channel wouls then be sent to the front left and right speakers and not output via the sub pre out. In such instances, you'd have no option other than to have the front left and right speakers set as LARGE. If other speakers are set as SMALL then frequencies at and below their associated crossovers are redirected to the front left and right speakers.


The above whereby you set the sub setting to NONE would be the best option for the OP while using the Bose speaker package, es[ecially if the sub wire or associated cable is faulty and if connecting all the speakers to the sub and not to the AV receiver.





All in all, I'd still suggest that the Bose package be replaced with a more conventional speaker arrangement.
 

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