Looking to upgrade the JBL "premium" speakers...

Re: Looking to upgrade the JBL "premium" speakers.

Sounds like your fixed on the Infinity or Polk. That's part of the listening enjoyment though, imo - to be certain what you perceive, as being the prefered choice..

Personally, I'd go with the Infinity. I assume you can get the "Factory fresh" sets at under 'authorized-retailer' market price, but again, you'ld afford the entry level 'authorized' Infinity components if purchased on Cardomain or crutchfield. (per $200 budget)

This entry level Infinity would produce your good, satisfying highs, imo.

However, if you're not going to add an external amp to power the components, you probably wouldn't need to spend over the $200 regardless, to get the sufficient sounds you're seeking!

p.s. '79 Supra?!? Ya mon!!

 

Re: Test Result: Frequency Response off of the amplifier

Thanks for all the great detective work man! We really should include all these sound modification articles into one KB or something, including the JBL wiring diagrams.

So the conclusion is pretty much what I figured by ear with a test tone cd I generated with Nero. There's a nasty sound dip at 160Hz which actually turns inaudible with road noise, there seems to be another above 1KHz which doesn't seem too noticeable, the bass is totally off, and it's probably not the entirely stock speakers fault for the messed up sound; it's the JBL amp.

Can we class-action against Toyota for the POS amp and sound? We did pay a chunk of money for it. :roll: They even have a |website|.

Anyways, would the cheapest/easiest/best way to go for flatter sound out of the JBL probably be to pre-shape it with a pre-amp parametric equalizer, and then post-pipe it through some proper crossovers/filters before it hits the speakers?

Anybody figured out if that Solara/Landcruiser amp could be a proper swap-in?

 

The more I think about it, the more it seems to me that bypassing the factory amp would be the real solution. Adding more equalization to compensate for the equalization in the amp seems like it will add more phase shifts and other equalization artifacts, and never end up with the pure sound that we want. But given how hard it is to replace the amp, equalization may be the only possibility, so shouldn't be discounted.

As far as bypassing the amp, it would be cool if there was a box that would do the following: Feed a sine wave or some other signal into the JBL amp. The output of the JBL amp would then be a variable volume signal. The box would take that output from the JBL amp as an control signal, used to determine what volume the JBL was requesting, and then would attenuate the signal from the head unit accordingly before passing it on to an outboard amp for processing. For extra bonus points it could use another channel of the amp output to mix in the beeps from the amp.

I don't know of any device that currently does this, so it would have to be custom made probably.

Another possibility I'm considering is converting the rear speakers into subwoofers: replacing the drivers with subwoofer type drivers, dynamatting the door, and using passive crossover/EQ to correct the bass response. That seems like it would be the best bang for the buck approach, but would take some effort to design a good passive crossover/EQ.

 

Tom,

Wow, good work, and thanks so much for doing this. I was planning to do this myself, and you've just saved me a bunch of time + effort!

One of my suspicions was that the center channel was partially subtracted from the front L + R, it's good to see that is not the case. The rest is pretty bad though. I knew the front channels were EQed pretty significantly, but the rears (and the extent of which) are a bit of a surprise.

I too am curious about whether or not lowering the bass tone control will tend to flatten the 80 Hz hump (it looks like 70 Hz on your graphs?). I might have to test that. I'm not surprised about this freq "hump" after listening to the system for a few months. One of my complaints is that it's boomy, which I previously attributed to the woofers' Fs - now I know it's intentional :roll:

Based on that, I think you're right about it being an 'illusion of bass' or 'loudness' curve, as opposed to a correction for interior resonance.

Quick question - is there any room between the stock speaker and the front door's interior panel, i.e. could a driver with a larger magnet be shimmed up/out a bit to miss the window?

 

Re: Looking to upgrade the JBL "premium" speakers.

Hi Wilco. Thanks for pointing out that the peak is at 70Hz not 80Hz... I was reading my graphs wrong!

I listened to a sweep test track and I observed that the response in the graphs appears to be audible; I heard a definite peak centered around 70Hz, and a few ups and downs further up that generally seemed to correspond to the graph. So not all of the eq in the amp is compensating for interior resonances (or at least not successfully That is what makes me think that just bypassing the amp would be the way to go if only it were possible.

I disconnected my center channel and I'm not sure whether I prefer it that way or not... will have to listen some more to know. It definitely changes the sound. I will also want to do some "panning" tests (from home theater test CDs) to see how the imaging ends up with the center removed. It could be that it's encoded like a center channel speaker in home theater, in which case removing it would result in loss of non-stereo sounds.

What I'm now thinking is:

1. Put good speakers in the back, and generally try and seal that up as much as possible. Drive them off of an external "sub" amp crossed over very low at perhaps 40Hz low pass, from the front JBL amp woofer outputs. A 12db/octave crossover in the amp would basically cancel out the roughly 12 db/octave slope of the jbl's front channel amp output, and the 70Hz hump in the JBL response would effectively serve as the new crossover point.

2. Use the rear channel output from the JBL amp to drive a new good set of front speakers.

3. If and when someone comes out with a solution for bypassing the JBL amp, use it and drive everything off of a separate 4 channel amp directly connected to the variable head unit outputs with all channels full range.

As far as how much space there is between the interior plastic and the speakers, that is a good question. I was thinking the only way to measure that would be to stick things into the holes until they hit the speakers and see how far they poked in.... not for the faint!

 

I keep coming up with different plans for what to do in my car...

• Replace the front speakers.
• As above, and run a 2 channel amp off the JBL's rear outputs (along with the rear speakers) to run the front speakers.
• As above, but a four channel amp.
• As above, but replace the rear speakers too
• Junk the JBL amp. Use an equalizer box with a volume control, mounted in the pocket below the stereo, to provide volume, balance, and fader adjustment (and any equalizing necessary). Use its outputs to drive a four channel amp. I'd lose the steering wheel volume control, but mode and up/down would still work.
  • 
    Any thoughts? In spite of working at my uni's radio station for a while, I still know jack about audio, so are these ideas sane?
    
    I'm leaning towards #1. If it isn't sufficient, I can always move on from there.

 

Re: Looking to upgrade the JBL "premium" speakers.

Looking at an older |thread| looks like Dion has tried putting in an equalizer post amp with anecdotally good results, ignoring phase issues, etc.

Looking online for what the equalizer could be, I found this 200W (not clear if it's peak or RMS) 12-band at |eTronics| (coincidentally same place to buy the Kenwood SW1 bass) for $20 (|manual| ) with 2|4 channel out.

Or, this 7-band |equalizer-amp| from Legacy with 2|4-channel out for |$22|.

So cheap enough to get 2 of these to shape the front and rear outputs from the JBL if there's no issues putting these things in-line.

 

FourOhFour, I wouldn't simply replace the front speakers because the signal to the woofer is low passed and the signal to the tweeter is high passed. A new speaker system connected to either input would not be full range and so wouldn't sound good. Replacing the woofer and tweeter directly (without adding a crossover) might give clearer mids and highs, if they happen to have similar impedance and crossover/resonance points as the factory speakers. But if not the sound could be worse with the fronts simply replaced. I'd definitely go for the amp driven off the rear channel if you replace the front speakers.

NuShrike, personally I wouldn't go with those equalizers; I'm not a big fan of graphic equalizers; they are simultaneously too broad (sliders cover too much frequency range) and don't have enough resolution (can't adjust Q (frequency width) or center frequencies). I'd use a parametric equalizer if anything, with adjustable center frequency, Q, and boost/cut level. That one you linked to only has 30 and 60 hz sliders in the bass region. I think that a 45 hz "variable bass boost" circuit like many amps have might be more useful.


Another idea that I'm starting to warm to is just throwing an aftermarket head unit in the slot under the radio and running all new speakers off of that. I find today's head units are powerful enough that you don't really need an amp. But it would be a shame to give up the tape player, dash CD changer, and steering wheel controls.

 

Re: Looking to upgrade the JBL "premium" speakers.

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That is a really good idea, but there is one potential issue: a low E on the bass is around 40 Hz. If the music you listen to has a significant amount of bass in the 40-80 Hz octave (so basically all rock, blues, jazz, country, pop), that's a lot of sound info in the freq band (40-70 Hz) that would be seen by both sets of speakers. Phase/time delay and transient reproduction might be a concern, especially if you want "tight" bass/drums.

I know none of that is news to you (tmorrowus), I'm just thinking out loud. I've got a few unfinished ideas rolling around in my head, but I'm running out the door - I'll post more later.

 

Re: Looking to upgrade the JBL "premium" speakers.

Decided to move this post to its own thread, since it really doesn't have much to do with speakers (though I want to replace those as well).

 

Wilco, I'm not sure I understand your comments about the bass being a problem. What I was contemplating was basically using the rear speakers as subwoofers covering everything below the 70Hz JBL peak. The fronts would basically cover everything above 70Hz.

The tricky part was that I was going to have the aftermarket rear amp output a signal that falls at 12db/octave in the 40-70 region (and beyond), while the JBL front channel rises roughly 12db/octave in that region. So they cancel each other out and provide roughly flat response in that region 40-70Hz. Actually since the JBL doesn't actually fall at quite 12db/octave it would be be a falling slope in that region. a 45Hz bass boost function on the aftermarket amp could be used to give more bass; I find flat amp output in the bass region doesn't produce enough.

That shouldn't be too bad as far as time-delays... the rear speakers are about the same distance to the driver's ears as the front speakers.

But perhaps it would be best just to avoid the whole hassle with the JBL amp and tap in before it, and just amplify everything aftermarket, using an aftermarket volume control by the dash. I think that's my current thinking. Eliminates the Analog->digital->analog conversion in the JBL amp and any EQ artifacts. I hardly ever use the steering wheel volume controls, prefering the dial control. So another dial mounted even closer might even be more convenient, if just a big uglier.

 

Yeah, I got what what you were saying, and I think it's a good idea.

My thoughts were that a 2nd order crossover has an output that's 180° out of phase from the input (easy fix), but the JBL's slope isn't exactly 12db/octave so there might be a minor phase difference between the fronts and rears, and with a shallowish 12db/octave slope, notes in the middle of the crossover range - like the open A string on a bass @ 55 Hz, or even the "thump" of a kick drum - would be roughly equal volume on all four speakers, yet the front left is closer to your ear than the rear right.

Considering that it's a car and not a home theater or concert hall, I doubt any of that really matters... like I said, I was really just thinking out loud.

 

Good explanation Wilco... you are ahead of me on that one. I used to get really concerned about such phase shifts because it's something that can be figured out intellectually and you can see how wrong a given crossover is theoretically. But then I began to see that there were some really great sounding speakers with 18db/octave crossovers which are theoretically not so great in terms of phase. Since they sound great in the real world I became less concerned about it. As you say this is a car and so I'm thinking that the boundary effects and whatnot will easily dwarf those kind of issues.

 

Re: Looking to upgrade the JBL "premium" speakers.

Hi All,

An update on the speaker replacements (see earlier post in this thread):
1. Made an appointment with the installer (recommended through Toyota of Whittier) to meet me to inspect/remove the speakers
2. Happened to be at Circuit City in City of Industry and saw an installer who'd done my son's 280ZX several years ago. Went in to listen to the Infinity 6012I and the Polk DB650 (2-way, 6.5" speakers). Felt that the Infinity's had a good tight base, bright highs, while the Polk's were accurate in the midrange (voice and horns). Went with Infinity
3. When the installer, Jamie, pulled the tweeters, he found that the installer's brother had taken a feed from the woofer/midrange (probably thinking it had not been crossed over. THIS is the reason the tweeter had no sound - only freq's feeding it were probably < 10K.
4. Installed the 6012's with the original JBL tweeters and am happy. Center speaker unplugged.
5. Will likely replace the rear woofer/midrange with 6012's.
6. The reason I did not go with the Infinity/Polk separates is that the crossovers are not used at all in my system, and that the woofer/midrange units are the same in the components. However, would like to hear from someone who tried the 6010CS with the JBL head unit/amp, just to see if the tweeter is sweeter.
7. BTW, tried to call the installer (who was supposed to meet me today at the dealer to troubleshoot their installation), left a voicemail, no reply. Called the dealer at the appointed time - installer had not shown.
Lesson learned: Any good installer can take the instructions on this site, plus his own professionalism/enthusiasm and make it right. I had gone with the Toyota dealer's suggestion because I felt the installer knew something about the Prius JBL system.
8. Does anyone know of a good replacement tweeter for the JBL?

Thank you for reading this long post.

Thanks.

 

Mike,
Is this right... you have the JBL system, and have replaced the front mid/woofs with the Infinity 6012 2-way in the front doors, and the rest of the system is stock? If so, I'm kinda curious how it's wired, i.e. which signal feeds the Infinitys, are the stock front door tweeters connected as well, etc.? I'm also curious why you opted for the 2-ways over the components?

To give you an answer to "8" above - IMHO any quality aftermarket tweeter would be better than the JBLs, but more specifically, since you already have the Infinitys, why not go with the REF1011T ?

 

Re: Looking to upgrade the JBL "premium" speakers.

Wilco,

Yes, probably should have gone with the component 6010's, but again, hoped to take advantage of the coax on the 6012's. Not sure what tweeters come with the 6010's, but didn't need the crossover (or so the posts have indicated). Though a good amp would probably improve things overall, I will look into the REF1011T's. Am returning the Blaupunkt's to Crutchfield - if any credit is given, will apply toward the Infinity REF1011 ($79).

You are right, the entire rear door assembly is stock, the original tweeter was reinstalled, and the feed to the original mid/woof now feeds the 6012's. The bass is tight, accurate, clean (my taste is not in excessive bass), midrange has percussion and voice imaging only heard on my home system. I guess I'd like some clean highs, but was concerned about the posts that indicated the front tweeter signal was not optimal.

Wilco, update me as to the system you are running now.

I thank you and other Prius enthusiasts.....

mike

 

Re: Looking to upgrade the JBL "premium" speakers.

The 6010cs comes with the 1011T tweeters, as can be seen in this thread:

http://www.priuschat.com/forums/tweeter-re...nt-vt10300.html

Buying the 2-way Infinitys, and then leaving the stock JBL tweeters (POS) in place, rather than component speakers like the 6010cs makes no sense at all to me.

By the way, if you think your car stereo "images" as well as a home stereo, you either don't know what imaging is, or you own the world's crappiest home stereo. Even the best car audio system I've ever heard (Mark Levinson system in a Lexus LS430) can't hold a candle to even a modest home system. Physics makes it impossible for a car stereo to image like a home system. I mean, think about what you wrote. The sweet spot in a home system is sometimes only wide enough for one person, and you have to have your ears at just the right height. You think a car system, with the woofers near the floor, you sitting three feet closer to one channel than the other, and with all of the reflecting surfaces - it's going to image like a home system??? I don't think so.

 

Mike,
Yeah, the 1011T is the tweeter that comes in the component set 6010 (which is the same 6.5" driver as the 6012).

As for coax vs. component, coax works best when the listener is square to the speakers. When the listener is off-axis, components are a better choice because the tweeter can be aimed easier due to its smaller size. In the Prius you (in the driver's seat) are close to 90° off-axis to the left door woofer (actually, all seats are well off-axis to all woofers), yet when you look at the "sail" panels that hold the tweeters, you'll see that they are aimed toward the front seat occupants.

Another reason to go with component set replacements is that the JBL tweeters are terrible IMO.

My advice (if you care) would be to get a set of 6010 comps for the fronts, and move your 6012 coaxs to the rear doors, and disconnect the rear door JBL tweeters.

As for my car, it's bone-stock. I haven't done anything to it yet.

 

Re: Looking to upgrade the JBL "premium" speakers.

Prius Envy and Wilco,

Thanks for your replies.

You are right concerning the tweeter placement. As it is nearly at the level of my ears and high frequencies are very directional, the placement is okay, just need to consider your advice re: the 1011T's.
It really is okay about the 6012's as the coax unit can be rotated upward to (more or less) help with the direction.
What I meant about the imaging is that when a piece is recorded, the placement of the individual instruments 'appears' to have a spatial depth. You are right, PE, guess I was too happy about the change from either the stock JBL woofer/mid OR the Blaupunkt's. Nevertheless, I like the sound and as others have mentioned, perhaps the most expensive part of the sound system will be your ears. Tried adjusting the left/right balance, but find that the separation of channels (with the center speaker detached) is sufficient if left at center.
Wilco, will consider your original suggestion re: the 1011T's and may match the rears with Infinity's.

Again, thank you both for your viewpoints and advice.

mike

 

Re: Looking to upgrade the JBL "premium" speakers.

I finally got around to installing my other pair of Infinity 6010cs component speakers in the rear doors of my Prius. I learned a few things in the process:

1) The JBL woofers in back are not as as bad as I thought. The Infinity woofers are still better though. Drums have the "snap" that they should have with the Infinitys, with the JBLs they're just a muddy mess. The Infinity tweeters are far far better than the JBLs.

2) You can't judge the sound of the rear speakers properly from the driver's seat in any car, but especially the Prius. When I first hooked up the left rear speaker, it sounded so bad I thought the crossover was defective. When swapping the crossover made no difference, I tried a direct hookup, with little change. So I thought the driver was defective, but I tried the other, plus a 6012i coaxial speaker I had taken out of my Jeep, with no improvement. Finally I hooked the 6010cs speakers back up with the crossovers, moved to the middle of the back seat, and found that everything sounded fine. I've never owned a car where there was such a huge difference in the sound of the rear speakers depending on where you sat.

Here is a picture of the speaker mount. My Infinitys (bought on Ebay) didn't come with the Intermount III mounts, and I was impatient, so I bought a pair of Scosche SAC656 speaker adapters, and mounted the Infinity metal ring mounts to them, then mounted the speakers to the metal ring mount. Following the speaker mount picture are two pictures of the stock JBL woofer.