Yammy RX-V2500 2nd sub connection

[math wizard]

I have a Yamaha RX-V2500 receiver. Currently I have a powered sub connected via the sub pre-out. I have a Polk RM-1000 passive sub laying around that I would like to use. Can I connect this sub to the front channel B-terminals of the receiver or must I connect it to the A-terminals (along with the front channel speakers). Currently, I have it connected to the A-terminals. If connected to the B-terminals, I will be able to disable it without disconnecting it. If connect to the B-terminals by itself, will it damage the receiver? I not sure about the impedance of this sub, but I think it is 8 ohms. Any suggestions.

 

[Adam]

MW,

Some questions for you to help with suggestions, if you don't mind:

1. Does the RM-1000 have an external dial for the cross-over frequency?

2. Because you're already using a powered sub, you're probably using the RX-V2500's bass management. Do you have the front speakers set to large or small?

In general, I don't think that it will hurt the receiver to plug the sub into the "B" speaker section. It sure shouldn't. The owner's manual specifically mentions how to connect to both "A" and "B" for biwiring, which is similar to what you'd be doing except that your woofer isn't in the same cabinet.

If you have your front speakers set to "small", though, I don't think that it will do much good to have the passive sub connected to either "A" or "B" because the RX-V2500 won't be sending much low frequency content to the front speakers. I'd like to know if you noticed much difference when you connected it up in line with your front speakers. Thanks.

 

[math wizard]

1. This sub doesn't have an external dial for the cross-over frequency. I think the sub is rated at 35 - 200 hz.


2. I am using the receivers bass management for the powered sub. I have the front speakers set to "large" (only way to get sound out of the passive sub) and bass out set to "both" so that I can get front channel bass out of the powered sub also.

 

[Adam]

Without a means of setting a cross-over frequency for the passive sub, just realize that if you have it connected independently from your front speakers (i.e. use "B" jacks for the sub) then both the passive sub and the front speakers will be playing frequencies between the low end of the front speakers and the high end of the sub.

For example, if the front speakers go down to 55 Hz and the passive sub goes up to 200 Hz, this would lead to higher output from 55 Hz to 200 Hz. That's ballpark because the response of the passive sub and speakers will naturally roll off at some point.

Ultimately, if it sounds good to you, then go for it. It's all about enjoyment. Your initial question was about damaging the receiver, and that shouldn't be an issue either way.

 

[math wizard]

The fronts are rated at the low end at 90 hz (130 hz at -3 db). There is some overlap but not much at the lower end. Thanks for your advice.

 

[jcPanny]

Passive sub

Math,
You will need an amp (external to the receiver) to connect the passive sub. Here are the required cables:
Receiver LFE output -> RCA Y adapter -> RCA to Sub amp -> speaker wire to passive sub.

The B speaker terminals on the receiver share the same amp channels as the A terminals used for your Mains. You can not connect a passive sub directly to the receiver. The LFE output will also take care of the crossover to the sub.

 

[Adam]

You can not connect a passive sub directly to the receiver.

jcPanny, why do you say that he can't connect it? I understand (and I believe that Math does also) that it's not the optimum set-up for sound, but do you think that it will damage his receiver? I was under the impression that his receiver will be fine.

 

[jcPanny]

Passive sub.

Reasons to toss the passive sub:

1. A low impedance could cause the receiver to overheat and go into shutdown. An 8 ohm sub in parallel w/ 8 ohm speakers = 4 ohm load. Many subs are as low as 4 ohms. 4 ohms || 8 ohms = 3 ohms

2. He does not have adequate crossovers causing the sub to overlap w/ the mains and can only connect to one of the mains. The mids on one of the mains will be higher causing a level imbalance.

3. The passive sub probably came with a HTIB and is worthless anyway. I wouldn't waste time or money trying to use it.

 

[math wizard]

This sub did not come from a HTIB. It was purchased as a sub-sat system about 14 years ago (Polk RM-3000). At the time, it was one of the best systems available (won many awards). Also, the system cost me $1000+ (hardly worthless). The manufacturers instructions on connection is to connect it in series with the satelittes. This can be done by either connecting the sats to the sub or connecting both to the same outout on the receiver. It has never occurred to me that connecting it in parallel with the mains would cause an impedance problem.

 

[jcPanny]

Reasons to toss the passive sub:

1. A low impedance could cause the receiver to overheat and go into shutdown. An 8 ohm sub in parallel w/ 8 ohm speakers = 4 ohm load. Many subs are as low as 4 ohms. 4 ohms || 8 ohms = 3 ohms

2. He does not have adequate crossovers causing the sub to overlap w/ the mains and can only connect to one of the mains. The mids on one of the mains will be higher causing a level imbalance.

3. The passive sub probably came with a HTIB and is worthless anyway. I wouldn't waste time or money trying to use it.

Math,
Sounds like the sub might be worth using. Pick up an inexpensive audiosource amp or a plate amp so you can connect it to your system without problems 1 and 2.