Different subs in pairs?
02-27-15: Zd542I know. That's why I put the smiley :-) Mgrif, given that the interference is being heard through the sub, obviously the rationale I stated for putting the clamp near the main amplifier is not applicable, and it would most likely be best to place it around the wires as close as possible to the sub. Regards, -- Al |
I was just kidding Al. Sometimes I just can't help myself. lol. Looking at your last post, I have seen this type of thing before. Not with home audio gear, but with pro audio gear. I remember a few instances where I heard a friends guitar amp, or other similar product, pick up radio stations. As you said, it probably wasn't FM because the stations we were picking up were from other countries. Honestly, I don't know what causes that to happen, but I have observed that same problem several times. |
Thanks for the feedback, folks. I only get the radio interfrence through the sub, not the mains. And, I only got it when I moved the sub farther away from my rig such that the cable connecting it was stretched out making an antenna. I've no idea if it's AM or FM, but I'll try the ferrite clamp. Then again, if I do combine one as wireless and the other direct hi level, I can go back to a short length of cable for the one near my rig. Probably still worth getting the clamps. I'll also ask REL about any timing issues, but given that they have three systems of hooking up a sub, wireless, hi level and LFE, it seems that latency shouldn't be an issue. Quick update - just picked up a pair of Martin Logan Dynamos to audition at home w/ their wireless system and, of course, the only inputs are RCA into the sub - no hi pass return or full return to the preamp. Given that I'm using a stereo preamp (no 2.1), and that the subs can't take a high level input, I can't use them. I don't feel like also buying a new preamp. Frankly, I like listening to music, not playing with gear. Looks like ferrite clamps and perhaps an S/3 wireless. |
If you were going to run two mono subs, then they could be different without, it seems to me, too much concern. If I was running mono subs (which in a way I am) I would want them to be identical for several reasons, not the least of which would be that if you want to even out room modes by having them in different places, you would (I think) want to make sure you are not introducing a second, different set of modes. But I'm no acoustician or speaker designer. Other reasons might include different crossover slope and/or execution, different frequency response, different absolute phase, different interaction with input device (espl if being driven from your amp) Maybe Duke, our resident guru in that area, will chime in. I know he has a multi-sub system that he sells that has identical subs. |
"If you can hear intelligible audio from the radio station, I suspect that it is AM and not FM which is being picked up, in which case you would want to select from among those listed under the "Low Frequency 200 kHz - 30 MHz" tab on the page I linked to. If the interference is other than intelligible audio, and/or you somehow feel fairly certain that it is indeed FM, select from among those listed under the "Lower and Broadband 1-300 MHz" tab. Or perhaps buy one from each category, and try both." Well, he did say the sub is musical. They do play a lot more music on FM stations. |
It might be best to ask REL about whether timing issues would be a concern in the scenario you are envisioning. Regarding the radio station interference, I suspect that could be eliminated (with no audible side-effects) by putting an inexpensive ferrite clamp around the wires from the existing sub, probably at a point near where they are connected to the amplifier. I would suggest that you take a look at the ferrite clamps listed here, and select one having an appropriate inner diameter. If you can hear intelligible audio from the radio station, I suspect that it is AM and not FM which is being picked up, in which case you would want to select from among those listed under the "Low Frequency 200 kHz - 30 MHz" tab on the page I linked to. If the interference is other than intelligible audio, and/or you somehow feel fairly certain that it is indeed FM, select from among those listed under the "Lower and Broadband 1-300 MHz" tab. Or perhaps buy one from each category, and try both. Assuming that the interference is being heard from your main speakers, and not the sub, I'm envisioning that the radio signal is being injected into the feedback loop of your amplifier, and its AM content is being demodulated as a result of non-linearities in the amp. Which is why I suggest putting the clamp near the amp end of the cable. Good luck. Regards, -- Al |
I see no issues using different model subs. But one wired and one wireless, I would be afraid (because I am a very cautious person, not because I am an engineer/scientist) of such different timing (time lag of signal delivery) between the two. I always try to keep lengths of pairs of wires exactly the same (ICs, speaker wires) to avoid this kind of issue. |
