BMW 2002 - Trouble Shooting

by CAE, Apr 01, 2002

I really appreciate your great help and great tips.Thanks,Victor Garcia

According to the product information, the Rockford RFQ-5000 is a surround sound processor that will take encoded or un-encoded 2-channel signals and convert them to discrete 5-channel surround. For instance you can play a regular stereo CD and the RFQ-5000 will derive the five main channels. Or you can play a DVD encoded in AC-3 surround and it will be played in five channels.

The RFQ-5000 is a unique device in that it works as in analog rather than as a Dolby Digital 5.1 decoder. This means that you will have regular stereo RCA input connectors rather than a fiber optic or coaxial bit stream input. For this reason you can connect an equalizer either before or after the RFQ-5000 and it will play, but only one way is really correct.

Many would be tempted to connect an equalizer to the input of the RFQ-5000, since you would only need a single stereo EQ (or two, if you chose to use both the front and rear inputs). Connecting the EQ this way will lead to the possibility that the RFQ-5000 cannot optimally derive five channels, since frequencies are being artificially modified before the input. In other words, if the RFQ-5000 "sees" a weird signal coming in, it will probably mess up the conversion to five channels.

The rule of thumb for optimum performance of a processor is to place a non-filtering processor before an equalizer (meaning that a crossover would go after the equalizer). The downside here is that you would require 2-1/2 stereo equalizers, or a 4-channel and a mono equalizer to cover all five of the full range channels. I am not sure if you want to invest that heavily. You can get away with not equalizing the rear channels, but that will still ideally require three channels of equalization.

If you already have a 2-channel equalizer, you can try it before the RFQ-5000 and carefully listen for any weirdness. Each product combination is different, so a little experimentation can reveal interesting things about a product's capability and operating range.

Perform a bit of logical research and you will begin to see where the real important points need to be managed. This will get you to your goal of serious SPL the fastest.

Q I was wondering if you could help me decide what kind of amp that I should get. I have one 10" Kicker Comp VR subwoofer, and right now I have a 300-watt Jensen amp that is supposed to put out 200 watts RMS and 400 watts peak, but I really doubt that. I've been looking for a new amp of a better quality, since the low pass frequency controls on the amp I have now are messed up, and I was thinking about going with a Kicker ZR120 which puts out 120 watts bridged mono, or maybe a Kicker Impulse IX702 which puts out 210 watts bridged mono. They both are about the same price. A guy at the store I was at told me that since the ZR120 is the top of the line of Kickers amps that it would make my sub hit harder and sound better even though it puts out less watts. So what is your opinion on which one would make my sub sound the best?Thanks a lot for your time. Nathan Brown

It's not difficult to confirm the amount of power that your Jensen is delivering. Use a digital multimeter with a "peak hold" feature and connect the probes to the amplifier's speaker terminals. Play something loud for a few seconds and read the measurement on the meter. Square the reading (multiply by itself) and divide that answer by the speaker load. The answer is the peak wattage that your amplifier is delivering.

The only way to truly know which amplifier will give you the best output and the best sound is to try it out. The guy at the store sounds like he is really confident in the performance of his Kicker amps. Talk him into temporarily connecting an amplifier in place of your Jensen for a quick tryout and see if you like the results!

What's the best way to use my Rockford Fosgate RFQ-5000 with an equalizer; that is, after my EQ or before?