How to replace front speakers and sub and with what ?

Question edited for clarity.
Question moved to Lexus LS430.

Check out the videos. There appear to be issues with the unit.

https://www.google.com/search?q=2001+lexus+LS430+mark+levinson+cd+playing+slow

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You can't hook it up to your preamp. If the sub has speaker level inputs you would use them to hook it up to your amp speaker terminals. The left positive and negative goes to the corresponding left positive and negative at the amplifier and the same for the right channel.

If you do not have your instruction book, there is often a diagram on the cover flap of the machine. Failing that try your local machien dealer they should show you how to thread at no charge. let me know how you go and I'll see what I can find.

Does the enclosure volume and style/type match the sub requirements? Are the subs wired correctly? I've seen lots of marking on the wrong terminal. Try switching one of the subs from pos to neg and neg to positive. It will be dramatic and very noticable if that's all it is.
Is your cutoff frequency correct for the sub? Make sure they're not getting full spectrum frequency. Are the Subs physically hitting any part of the enclosure at any point in the excursion? Are they screwed securely to the enclosure? Is the sub surround intact and smooth through the full extcurion? Is the amp ok? Got enough current throughout the system? Battery, Capacitor, Wiring, fuses, speaker wire etc. Bigger is better but always the correct fuse rating.
Signal from the head unit? Proper preamp wiring?

The cord you are wiggling is not an S-video cable, it is a Mini DIN 8 connector. Both S-Video and Mini DIN 8 are the same type of connector, (DIN) except the S-video is a Mini DIN 4.
I'm not sure exactly what the problem is, perhaps you could enlighten me with some more info? Have you changed any audio settings in the menu lately?
First, try unplugging your sub from the power for 30 secs. Then plug back in.
Then unplug one speaker (doesn't matter which one but keep track of what you've unplugged) from the sub, wait the 3 mins and see if it shuts of again. If it shuts off again then plug your speaker back in and repeat this step with another speaker, until you've found the culprit, or run out of speakers.
Let me know what you find.

Yes.

It's frustrating that KLH manuals seem impossible to find anywhere online BUT a simple picture will suffice...

Go here and supersize the picture of the rear of the sub...

http://cgi.ebay.com/KLH-Audio-Systems-Bassbite-V-Model-E214708-Speaker-/110673631693

Run your front channel speaker wires to the CLEARLY-MARKED connectors on the sub and daisy-chain your front speakers to the CLEARLY-MARKED connectors on the sub.

Adjust the sub volume to match the front speakers levels. This will give you local volume control at the Sony.

Check the bronze-colored coil underneath the foam cover. Note whether it looks worn, burned, warped or distorted. This may be the cause of your sub sounding fuzzy or muffled, which means it needs replacement.
Look at the fuse inside the speaker and test it if you know how. This is a likely problem that causes your sub to power up improperly, play sounds at about half the volume or intermittently fade in and out. If the fuse is discolored or shows a short, you'll need to replace it

yeh uhh u might wonna get the voice coil checked thats the problem with the speakers now days they dont really make them like they use to

Try playing with the connection, sounds to me maybe the jack is going bad or has a shorted connection. Plug it in and out slowly to see if that's the issue.

I found that they can hold up to 6 1/2" speakers and 2" tweeters. I'm not sure the specific mounting depth but i can almost assure you there wont be any 6 1/2" speakers that require a whole lotta space