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Review: Bi-amp on the KFC-XR600

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Old 06-07-2001, 09:17 PM
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I have finally run the extra set of wire to the kenwoods. Took me almost 3 hours of struggling on my back, but I did it . The key is use soapy water like djqube said... That made everything easy. I used zip ties to snake it then wet the wire down and pulled it right through.


Anyways, this post is about the kenwood bi-amp feature.... Does it make a difference? Hell yeah it does. Not only does everything sound clearer, but it can get louder too!

The trick is to use proper fading of back to front. The tweaters are less likely to distort at high volume. So, just fade it one or two clicks forward (to the tweater), now your highs are louder then your lows. This works great for driving with the top down.

I also think the addition of the monster 16-guage to the power hungry woofer made a huge difference. Hard to tell for sure, but at least I get that wonderful psychosomatic effect of believing it made a difference .

All you kenwood KFC-xr600 users out there give it a shot, I bet you will think its clearer and louder too .

-- Robert
Old 06-07-2001, 09:22 PM
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Thanks for the tip! I might try it. You are right that the KFC xr600s can handle a lot more treble than bass when wired without bi-amp. I'm using the stock wires and I have used the CDA-7876 hi pass filter feature to cut some of the distortion. At low volumes I turn off the filter.

Did attaching that "antenna/amp" wire improve your radio reception?

Barry
Old 06-07-2001, 10:19 PM
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I hooked it up when I wired the speakers up. I haven't checked to see if it made a difference ... Having 144 songs on a disk kinda eliminates the need for a radio . I'll check it out tomorrow.

-- Robert
Old 06-10-2001, 02:50 PM
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Gold,

I'm assuming from your post that you have an MP3 Cd player and not the original head unit. I was looking at biwiring those speakers with the factory head to see if it would make a difference. I was hoping to forgo an amp but it looks hopeless!
Old 06-10-2001, 04:37 PM
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Should I tell him Pinky? Or do you want to.................
Old 06-10-2001, 05:04 PM
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[QUOTE]Originally posted by Goldtrom
[B]I have finally run the extra set of wire to the kenwoods. Took me almost 3 hours of struggling on my back, but I did it . The key is use soapy water like djqube said... That made everything easy. I used zip ties to snake it then wet the wire down and pulled it right through.


Anyways, this post is about the kenwood bi-amp feature.... Does it make a difference? Hell yeah it does. Not only does everything sound clearer, but it can get louder too!

The trick is to use proper fading of back to front. The tweaters are less likely to distort at high volume. So, just fade it one or two clicks forward (to the tweater), now your highs are louder then your lows. This works great for driving with the top down.
Old 06-10-2001, 10:51 PM
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Pinky:

First off, I don't think you understand how the Kenwood speakers work... They are esentially two speakers in one. Not just a two way speaker. The tweater has a single level high pass on it and its own +/- terimanls. And as far as I can tell the woofer has no filter at all (and yes another set of +/- terminals). It just accepts the full bandwidth. There is NO external crossover . When you listen to either the woofer or the tweeter by itself, it become apparent that they are producing frequencies that they are not meant to. Played together they blend very nicely.


Second, and most important I didn't say they were "that much louder then your passive cross over ". I said they can get louder because now you can control the clipping of the amp. Has nothing to do with the crossover whatsoever (which there isnt one anyways). If I supply less power to the woofer then the tweater, the tweater will be louder and the woofer won't suck down more power then the amp can provide. However, the major problem is now you don't have enough low to mids... but at least you can hear it without it distorting.

I've already begun plans to install a nakamichi PA-502 amp... So, I'll be going back to the old two channel mode of operation. Which by the way has to be changing the load on the amp. I don't have a multi-meter (its back in virginia with my parents), but I'm guessing that each speaker provides a 4 ohm load, and that when wired in parallel (like kenwood recommends) you get 1/(1/4+1/4) = 2 Ohm... not very good... I'm not sure what the heck e kenwood was thinking. This type of load is not good on THD nor is it good for over all power.


As for your comment about wiring your whole system off of two channels... Thats complete BS. There is no way you could balance all those loads with passive crossover networks. When I say no way.. I mean no way and keep same sound quality... You cannot tell me that running your power through all those passive components is going to maintain the same THD... BS... and you know it! I've wired several stereos off of one amp with 8+ speakers... I can tell you right now your distortion or volume will suffer... You can't have it both ways.


Finally, my third point... I even said that it is quite possibly a psychosomatic effect, do to my having spent so much time doing it. . I am a strong believer in believing. If you believe something is so then it is... why because your senses are the only ones you have... I don't want to go into to much about this since it is a philosophical argument. But, basically, there is no way you can verify your senses, since all information you gather is from them, even what you read "eyes" and hear from others "ears" is your senes.. For all I know you are all just in my mind and I'm making this world up hehe. But thats way too deep for a discussion on car audio.

If you disagree with any of my arguments, please do respond constructivly. Im willing to accept flaws in my techincal arguments... However, don't expect to change my philosophical ideas .


DJRobNM: Yes, I'm usng my JVC KD-SH-99... however, I would say you would still get better quality sound by wiring up the rears... Despite what Pinky has argued.

-- Robert
Old 06-11-2001, 04:48 AM
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Originally posted by Goldtrom
Pinky:

First off, I don't think you understand how the Kenwood speakers work... They are esentially two speakers in one. Not just a two way speaker. The tweater has a single level high pass on it and its own +/- terimanls. And as far as I can tell the woofer has no filter at all (and yes another set of +/- terminals). It just accepts the full bandwidth. There is NO external crossover . When you listen to either the woofer or the tweeter by itself, it become apparent that they are producing frequencies that they are not meant to. Played together they blend very nicely.

Whats happening is that the woofer is rolling off naturally and the tweeter is passivly crossed off. So the woofer is playing to high most likely and playing to low as well. That passive cross over is probably about S2000 factory stereo quality.(enough to do the job but far from quality)

Second, and most important I didn't say they were "that much louder then your passive cross over ". I said they can get louder because now you can control the clipping of the amp. Has nothing to do with the crossover whatsoever (which there isnt one anyways). If I supply less power to the woofer then the tweater, the tweater will be louder and the woofer won't suck down more power then the amp can provide. However, the major problem is now you don't have enough low to mids... but at least you can hear it without it distorting.
So what your doing now is driving both the woofer and tweeter with full range music.......making your tweeter play lower than it was before because it was crossed off. That will make it seem louder because you effectively have now 2 speakers playing the same music hence getting a 3db gain on each set of speakers.

I've already begun plans to install a nakamichi PA-502 amp... So, I'll be going back to the old two channel mode of operation. Which by the way has to be changing the load on the amp. I don't have a multi-meter (its back in virginia with my parents), but I'm guessing that each speaker provides a 4 ohm load, and that when wired in parallel (like kenwood recommends) you get 1/(1/4+1/4) = 2 Ohm... not very good... I'm not sure what the heck e kenwood was thinking. This type of load is not good on THD nor is it good for over all power.
If you cross them all off you can get a 4 ohm load at the amplifier. Kenwood knows that!

As for your comment about wiring your whole system off of two channels... Thats complete BS. There is no way you could balance all those loads with passive crossover networks. When I say no way.. I mean no way and keep same sound quality... You cannot tell me that running your power through all those passive components is going to maintain the same THD... BS... and you know it! I've wired several stereos off of one amp with 8+ speakers... I can tell you right now your distortion or volume will suffer... You can't have it both ways.
What happens is that if you think of music as a line going from 20hz to 20,000hz. You stop it at different points and then pick up at those points that you stop.(specifying a speaker for each range) Lets say your sub goes 20hz to 100hz then your 6.5's from 100-2,500 then your tweeter from 2,500 on up and naturally roll off. This way the amplifier sees a 4 ohm load from each speaker. There is little to no overlapping of speakers "lines". When you overlap lines you effectively 1/2 the impedence.(4ohms to 2 ohms though if done right there will be very little overlap and will not effect the amp adversely)

[/quote]
Finally, my third point... I even said that it is quite possibly a psychosomatic effect, do to my having spent so much time doing it. . I am a strong believer in believing. If you believe something is so then it is... why because your senses are the only ones you have... I don't want to go into to much about this since it is a philosophical argument. But, basically, there is no way you can verify your senses, since all information you gather is from them, even what you read "eyes" and hear from others "ears" is your senes.. For all I know you are all just in my mind and I'm making this world up hehe. But thats way too deep for a discussion on car audio.

If you disagree with any of my arguments, please do respond constructivly. Im willing to accept flaws in my techincal arguments... However, don't expect to change my philosophical ideas .


DJRobNM: Yes, I'm usng my JVC KD-SH-99... however, I would say you would still get better quality sound by wiring up the rears... Despite what Pinky has argued.

-- Robert
[/QUOTE]
This is a audio discussion I will leave your philosophy out of it. I just know the facts. Looks like you should get a good installers manual. Maybe even take a basic installers book and test your self on it. I did that and learned a lot!(plus almost 10 years in a stereo shop dosen't hurt!)
Old 06-11-2001, 09:08 AM
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I've never looked at bi-wired speakers, so I'll just address the points that I can...

[QUOTE]Originally posted by Pinky [B]
Whats happening is that the woofer is rolling off naturally and the tweeter is passivly crossed off.
Old 06-11-2001, 09:35 AM
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I don't mind an argument, but we seem to be arguing about different things. But, anyways, here I go again...

O.k. Pinky, you still seem to misunderstand my points. The kenwoods DON'T HAVE A CROSSOVER. They have single high pass filter. And I did not remove the high pass filter. It is still there... I'll say it again, what I'm doing to make it louder is changing the power supplied to the speaker most likely to cause clipping, the woofer.
The tweeter is NOT playing the full range.

Here is the definition of a cross over for those who don't know:

A frequency divider. Crossovers are used in speakers to route the various frequency ranges to the appropriate drivers.
Additionally, many crossovers contain various filters to stabilize the impedance load of the speaker and or shape the frequency response.
Some crossovers contain levels controls to attenuate various parts of the signal.

A passive crossover uses capacitors, coils and resistors,usually at speaker level. A passive crossover is load dependent (the transition may not be very smooth or accurate if a different speaker is substituted for the one the crossover was designed for).

An active crossover is based on integrated circuits (ICs), discreet transistors or tubes. An active crossover is impedance buffered and gives a consistent and accurate transition regardless of load.


You will notice that this definition always refers to multiple drivers (i.e., more then one). If you are only "filtering" out one range of frequncies then there is no "Crossover", now is there? It is simply a single (first-order, second-order, etc.)filter we are not spliting the frequncies with a passive or active device, we are simply filtering out one whole range.

If you cross them all off you can get a 4 ohm load at the amplifier. Kenwood knows that!
Well if this is true, then why didn't they either A. supply a crossover, or B. mention you need a cross over in the manual or on the box. Seems to me if they know it then they should tell their customers.


As far as reading books on car audio install... Sounds like a good idea... I have done it before (ahout 5 years back), maybe I need a refresher. I'm mainly just using my Georgia Tech knowledge from when I got my BS in electrical engineering. Hm, I guess all those years I spent learning about circuit & frequnecy analysis have gone to waste... tiz what your saying Pinky, right?


BTW, you never countered my argument on running a whole system off of one two channel amp. Can it be done? Yes. Should it be done? NO! Unless you have some super amp with specs 10X better then anything I've seen, you are going to increase the load on the amp beyond its design specs and depending on how you wire it, you will adversly effect one or another of the characteristics of your sound quality and power usage (i.e., volume).


-- Robert


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