Center Speaker Disconnect

can't this "problem" simply be solved just by adjusting the midrange?

 

OK, stupid newbie question...

I don't see any instructions for unplugging the speaker, only for prying it off the dash. Is it immediately obvious how to do it once you've pried the speaker out? Also, do I need to worry about getting a shock or anything from monkeying with the electronics?

 

When you lift the speaker assembly out of the dashboard, you will see the connector. Just disconnect the two halfs and put the speaker assembly back into the dashboard. There is no electrical hazard, but if you're still uncomfortable, you can turn off the radio then there will be no electricity in the wires.

 

Thanks for the help. I unplugged it this afternoon. I think my stereo sounds better now. Can anyone explain why - in layman's terms - removing the center speaker would improve the sound?


<div class='quotetop'>QUOTE(8AA @ Jun 4 2006, 11:37 AM) [snapback]265656[/snapback]</div>

 

<div class='quotetop'>QUOTE(SparkyJ @ Jun 4 2006, 10:03 PM) [snapback]265843[/snapback]</div>

The audio coming out of the JBL amp is specifically mangled and overboosted at specific points, in the 70Hz range (bass), the 2-4KHz range (hihats, cymbals, etc), and some others. Yes, JBL has preset/preprogrammed/burned-in equalizer settings for each of your audio options which cannot be turned off. Check out Tom's audio graph 4. You will never get the original pure audio because of JBL.

When you remove the center speaker, you cut out the center speaker's contribution to the overboosted 2-4Khz sound that you hear. Basically you just lowered the midrange sound volume level in a permanent way. The fortunate part is the drop of 2-3dB puts the sound right where it should've been if JBL didn't mangle it.

There is a possibility to reprogram the JBL amp, but who has the equipment to do this?

 

<div class='quotetop'>QUOTE(NuShrike @ Jun 5 2006, 06:09 AM) [snapback]265892[/snapback]</div>

so taking out the center speaker is basically a permanent/difficult version of lowering the midrange which can be done non-permanently/easily via the MFD audio controls? am i missing something?

 

<div class='quotetop'>QUOTE(electricity_guzzler @ Jun 5 2006, 11:12 AM) [snapback]266073[/snapback]</div>

You could try doing both. The center-speaker is a bit more narrow and focused on the area it covers like a band equalizer versus the midrange control which affects all the frequencies surrounding it like a parametric equalizer. You could say the Q for the mid-range control is too wide.

If you look on Tom's charts (graph 5 and 6?), the mid-range tone control is centered around 1KHz, which is off already, and affects way too much around it. I guess it would be nice if we went back in and found the tone settings that gave the most flat response. It was mostly given up last time, because it only aggravated the sound issues, rather than helping.

 

Okay, with a 2006 model and no JBL system, I have no center speaker. So, what is the best suggestion for improving the unbelievably crappy sound? I could throw a boom box in the seat and have better sound than this. Just amazing for such a technological marvel such as the Prius that they can't provide a "sound" (pun intended) audio product!

Thanks.

 

<div class='quotetop'>QUOTE(electricity_guzzler @ Jun 5 2006, 11:12 AM) [snapback]266073[/snapback]</div>

Well, no - not really.

Consider the center speaker as the weak link in the chain. It is a low quality speaker that can't hold up to high volume and has a narrow range. I really don't know what it's doing there.

 

<div class='quotetop'>QUOTE(dgstan @ Jun 9 2006, 09:38 PM) [snapback]269052[/snapback]</div>

It actually fills in the the missing sound range between 2-4Khz IF the sound coming out of the JBL amp was flat instead of the default hilly mess.

I've tried some cdrw of Nero anti-equalized pink noise, and I couldn't get that range filled in correctly on my RTA with the center speaker missing. So my Nero tuned cdrws sound absolutely great with the center speaker in, but only then.

So thanks a lot JBL/Harman Kardon! No wonder no serious audio enthusist uses your equipment.

So JL Cleansweep still and associated equipment or TRD Sportivo, hm..

 

I have a slightly different take on why disconnecting the center can improve the sound quality:

1. The center speaker is aimed at the windshield rather than the listener, so you are hearing reflections off the windshield. In general sound quality is best when you get the sound direct rather than reflected.

2. The center speaker signal is at a different distance to listener from the left and right speakers. Because sound travels at a finite speed, it will mess up "impulse response" a little by making the same sound arrive both sooner from the center and later from the right speakers. For best sound you want the sounds to arrive as much as possible at the same time.

3. The center speaker is different in design from the others and therefore will impart a distinct spectral response. This could be corrected out in theory, but in practice it looks like Toyota used a passive crossover for it, which doesn't have the ability to correct the response as well as the digital active crossover used for the overall front stage.

4. The center speaker isn't mounted particularly robustly. Whereas the front woofers are rivited to strong sheetmetal, the center speaker is just clipped onto relatively flimsy plastic dash material, and the clips have some play in them where you can move it around. Even at the midrange frequencies this covers, minor amounts of flex might smear the sound a bit and allow resonances to enter.

Having said all that, everyone should try it both connected and disconnected. Once you know how, you can lift the center grill with your fingers and unclip the connection in a minute or less. Then you can plug it back in and repeat as many times until you have an idea of how it helps or hinders.

<div class='quotetop'>QUOTE(electricity_guzzler @ Jun 3 2006, 12:06 AM) [snapback]265044[/snapback]</div>

No. The midrange adjustment affects a relatively narrow frequency band, while the center channel covers a much wider frequency band.

 

The best way to improve the sound of the JBL system is to disconnect all nine speakers.

I can't imagine how low your standards must be if you find the sound out of them to be satisfactory.

 

Wouldn't books on tape, news programs and bluetooth phone calls sounds better with the center speaker left connected? The overwhelming consensus seems to be that music sounds better with the center speaker disconnected, but what about voice?

 

The center speaker area also is a good place to run wires behind the dash. I ran the power cord for my roady through this speaker hole to the power outlet on the passenger side; no wires coming down the fronnt.

 

<div class='quotetop'>QUOTE(nyprius @ Jun 10 2006, 07:04 AM) [snapback]269147[/snapback]</div>

The phone only uses the driver-side speaker as far as I know.

 

<div class='quotetop'>QUOTE(nyprius @ Jun 10 2006, 10:04 AM) [snapback]269147[/snapback]</div>

In my experience, NO!

The problem I had was that the center speaker grille buzzed frequently with a male voice, especially with vowel sounds (certain vowel sounds approach the shape of a sine wave, which, when at or near the resonance frequency of the grill structure--apparently right in the middle of the male voice range--will really cause a nice buzz). Since most audiobooks are narrated by men and I listen to audiobooks every day during my commute, disconnecting the center speaker was a great source of aural relief. I hadn't even thought of that until I came across this thread.

I can also confirm that the phone sound is completely unaffected with the center speaker disconnected.

- Doug

 

<div class='quotetop'>QUOTE(electricity_guzzler @ Jun 3 2006, 01:06 AM) [snapback]265044[/snapback]</div>

No. With audiobooks and other audio with predominantly male voices, the speaker grille frequently buzzes. Turning down the MID control doesn't make it go away, and it sounds really bad.