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February 12, 2013 - 8:06pm
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Poor Bass with new sub
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Does the sub have a gain control? Sounds like it isn't providing enough gain through the rca input. That's why most subs I'm familiar with have gain (volume) control. I doubt the amp has too low an output, but I guess it's possible.
EDIT: Read it again. Looks like you tried the volume control. I'm kind of stumped now, though one thing I notice is that the Jolida JD 1701 specification has a lower +/-3 dB limit of 22 hZ. I don't know if that applies to the pre-out, but that's not good number for sub bass.
Two issues.
First, subwoofer positioning is critical. If you put the sub in a site where there is a room null (or a few) in the low bass, it will be impossible to get much out of it. Try moving it around. Same applies to the listening position.
Second, the relative gain of the preamp out + sub amp with respect to the Jolida amp is relevant. Try the sub on the speaker outs just to see if that applies to this situation.
Use the variable output jacks to connect to the sub. Put the sub in your listening position, play bass heavy program material and crawl around to find where the bass sounds the loudest. Then place your sub at that location.
Ok so I finally got around to hooking up the speaker wires to the sub instead of the RCA cables. Well that seems to have fixed the problem as now I have to turn the sub almost all the way down. I guess the real question now is if the RCA problem is in the 12 year old sub or the new Jolida amp. My guess is its in the sub, but I am not sure how I can verify without another sub.
IMO the amplifier output you are using to feed the subwoofer is probably defective or the wrong one.
Actually, I see no mention of a preout or subwoofer output jack when I look at that amplifier' s information, so I wonder what you WERE using to connect to the subwoofer.
It appears that wiring the sub to the speaker terminals was your only option in the first place.
preamp output jacks. The variable output has a maximum voltage of 1.8 volts and is intended for connection of a power amp or powered subwoofer. That output might not be a good match for the input sensitivity of the subwoofer.
Thanks Jackfish you are correct. Commsysman the Jolida website is not very good and you are correct it does not list all the outputs on the website.
The sub is an Infinity BU2 which has RCA line level inputs with a sensitivity of 70mV and an impedance of 12K Ohms. Does anyone see a problem with the maximum voltage of 1.8v of the Jolida amp combined with this sub?
The sub is probably 12 years old and the RCA inputs have never been used before now. I am really not all that concerned if they dont work but at some point I would like to upgrade to a newer sub and use the RCA inputs on the new sub. So verifying the amp's RCAs work is really my concern as the amp is new and still under warranty.
Any suggestion on how I can test these to verify?
Up to 1.8 volts into 70mV sounds fine. I don't think the impedance is a problem either. A higher input impedance lessons the load on the pre-amp I believe. Keep in mind, the Jolida will not put out 1.8V unless its input is getting a high enough signal. But I still don't see a problem with the specs.
All I would do at this point without measuring equipment, is try the sub with a different pre-amp, and the Jolida with a different sub. It may very well be that the thing is broken.