sparky3489, I have a question for you regarding the equalizer to a sub...?

Question

I noticed your replies to a previous "inquirer" about hooking up the 6x9's and subs to an equalizer. I'm going to be purchasing a new mazda soon and don't want to get rid of the factory HU. I was going to put in an equalizer to adjust the sound to my likings. I have hopes of installing two 6x9's and one 8" sub in the rear deck of the car. I want to power them with a kenwood 2 channel amp with a tri-way crossover (which I guess I need advice about that too Lol!). The equalizer I'm looking at has specifics for the subwoofer itself. To me, that seems like it would help prevent the higher frequencies from getting to the sub. Please correct me if I'm wrong because I wouldn't want to mess up a system. I'm asking you directly because I've read over several of your answers to audio related items and they are clear and make an incredible amount of sense to me. Thanks in advance for any advice you can give me!

Amp - Kenwood KAC7202 150Wx2
Equalizer - Pioneer DEQ 7600 15 band digital EQ
Sub - 8" Polk MM2084
6x9's - Pioneer ts-a6991r 5-ways

I'm not looking for competition stuff, but I don't want to risk shortening the life of any of the audio equipment that I buy. And these particulars could very well change as I'm SEVERAL months away from being able to do the custom install. Neither of the mazdas i'm looking at have speakers established in the rear deck. Gah...the madness...

Valid point sparky, I never sat and thought about the obviousness of the crossovers making it a 5 way. Hmmm...time to revise the plan a little bit.

Thanks for the advice and keep it coming Hoghead and Sparky!

Answer 1

Hoghead is right.

"when bi-amped with a two way crossover, it separates the highs and lows, usually selectable by frequency."

He's saying by using two amplifiers and (by either means of a crossover before the amps or utilizing the LPF/HPF that's built into each amp) separating the upper and lower frequencies to their respective speakers (subs or 6X9's), will be more effective than an EQ.

Another reason to use two amps is that depending on how you wire 3 speakers (two 6X9's and a sub) to a 2-channel amp gets tricky. Improper impedances can have undesireable results.

You want to match the RMS watts between speakers and amps.

That is, if your 6X9's are say, 150 watts RMS @ 4 ohms, you'll need an amp that is 150 watts RMS X 2 @ 4 ohms.

The same with your sub, if it's 200 watts RMS @ 4 ohms, you'll need a 200 watt RMS @ 4 ohms amp.
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I just noticed your 6x9's - Pioneer ts-a6991r 5-ways.

"5-way" means it already has crossovers built in to the speaker itself. So an EQ is really a moot point.

Answer 2

Hello from HOGHEAD.

I don't deal with car audio, but I am an audio professional and have been for many years owning and operating a sound reinforcement company.

It is the electronic crossover that you referred to that separates the full frequency band into "sections", when bi-amped with a two way crossover, it separates the highs and lows, usually selectable by frequency. For example, if the crossover is set at 100 Hz, the all signal at 100 Hz and below will be sent to your subs, with the balance of the signal sent to your full range speakers.

An equalizer can get close to this, if it is a full 1/3 octave (31 band) graphic EQ or a "parametric" EQ, which has "sweepable" frequency control. You can roll off all high frequencies and do some "filtering" of frequency response in this fashion, although this is a poor choice.

An equalizer does just that; it equalizes. What does it equalize? EQs are usually used, in this instance, to make up for deficiencies in speaker frequency response, boosting where necessary or cutting where needed, trying to "flatten" frequency response so the it is equal acroos the audio spectrum, which is 20 Hz on the low end and 20kHz on the top end.

It is also used for "tone shaping", or, getting it sounding the way YOU like it.

The other advantage to bi-amping with a cross over is it helps the amplifier in its efficiency. Amplifiers have a spec called "slew rate". This is the amount of time/voltage it takes for the amp to reproduce the signal given to it to process. The higher the slew rate, the more accurate the reproduction of program material.

As an example, suppose there is a series of very high notes played, followed by very low ones, or vice versa. In full range, the amp has to be fast enough to reproduce the low and all of a sudden go to it's top end, in a hurry.

When a crossover is used to separate the frequencies BEFORE it ever gets to the amps, then all they have to do is accurately reproduce the portion of the frequency band assigned to them. This improves performance, the amps don't have to work as hard, and slew rate, while still important, is not as much of a factor anymore.

Hope this helps till sparky checks in.................