OK, so the dynaudio's went in the front doors a few months ago. Dramatic effect, as I have posted. However, the more I listened to it the more something strange was going on. It was like the soundstage was being dragged backward somehow. Using the fader didn't really help it (this was a surprise to me). I was going to put ADS 336ims in the rear doors but they are impossible to get so I got some ADS 236ims (only difference is the 236 does not have the rotatable tweeter) and installed them. Once again, THE BOOK makes life a lot simpler. Installed with the DEFLEX panels and some CAE sound deadening. Only mod from the book was taking the Dremel tool to the door panel to open up the plastic behind the grill. With the fader turned all the way to the back, the speakers are very, very unimpressive, but with the fader set at zero there is a very noticeable effect. The dyns have come alive to a different plane. There is better separation and far more presence in the front soundstage now. I am not sure if this the effect of better rear fill (maybe Percy or Mean Gene can tell me if I am hallucinating or not) but, as I said, the sound from the dyns has really come alive. Next step is the dyn sub to replace the stocker (still hasn't been delivered) and I have a feeling the MC446 is in my future, I believe that I need to keep the head unit down to reduce distortion. In any event, if you have just done the front door speakers, do the rears with an upgrade. The difference is noticeable even to my old ears. Have to get the front door speakers and look at them again, the stock rears are quite clearly marked 4 ohm so there is no impact on power to these from the stock setup as the ADS's are also 4 ohm.

 

When I run my two front speakers without the rear fill it sounds like there is a huge suckout in the kickbass area, which I guess is cancellation due to wavelength. Dialing in the rear speakers fills this area in. That's what I hear, anyway.

I measured the frequency response of the stock speaker against the Vifas that I installed recently. Despite their higher impedance, the Vifas (with a slightly larger cone area) had exactly the same sensitivity. However, the Lexus drivers "sound" much louder in comparison. That is definitely down to their screechy sound and all the distortion they produce in the midrange. That would explain why the soundstage in your car was pulled to the back.

Stevie

 

stevie - You are absolutely correct. The stock speakers did sound louder than the ADS's with the fader put on full rear but I have no intention of going back. With the fader at "0" the sound is much better and fuller now. Might not be any louder but it sounds much better. Maybe this is old hat to a lot of people here but it did surprise me. I doubt anyone who is upgrading would leave the stock rear speakers in but having lived with them for a while I can definitely hear the difference with them gone now. On to the sub, if it ever shows up.

 

Ron - something else I noticed was that the Vifas will take much more power than the stock speakers before distortion. It's the stock speakers that limit the output of the stock system, not the amp.

I'll get to do the rears in a couple of weeks.

Stevie.

 

stevie - Even with that impressive five pounds of plastic surrounding them, it looks obvious that any aftermarket speaker would handle more power and distort less than the stock speakers. I actually thought that the Premium system was not bad, still do, but goodness what a difference good speakers make. It's a shame that most auto makers, including Lexus, are so skimpy on the base sound systems. Come on guys, it is time to improve audio systems across the board not just the top end units. Then again, it leaves us tinkerers room to improve things and make the cars our own. I am getting the impression that the stock amp is a weak link and while I like a lot of the gee whizz features in the aftermarket head units I very much like the look of the stock built in HU. Want to keep it as long as possible. Good luck with the rears and post your impressions. I thought I was going a little crazy with what I noticed. Couldn't figure out if I was just hearing things (very possible) or there was a definite effect. I am really marvelling at the front speakers, they have come alive now that I have replaced the rears. Hopefully you notice the same thing. But man you are so right about the volume from the rears. It doesn't help that they are at ankle height but upgrading definitely changes the "fill" characteristics. Wish one of the gurus would make some comments on all this.

 

I'm not one of the guru's and I'm not familiar with the GS or even rear door speakers (never had a car with them); but I'll throw my opinion out there.

I personally don't use rear fill; in many cases it detracts from the front soundstage (pulls it back like you were describing at the beginning of the post). I use one set of components in the kickpanels with plenty of power and it doesn't lack anything IMO. Sound has more impact and is more life-like coming from in front of you, so I believe in very little if any rear fill. Very low volume rear fill can help the front stage, especially with some crossing over and tinkering with positioning and time alignment. The rear speakers can be used to simulate the little bit of sound that bounces off the back wall of the imaginary concert we're trying to achieve.

I'd get those Dyn's a bigger and better amp, I think you'd be glad you did.

Oh yeah, in my experience, any distortion or that sort of thing will be easier to localize, which could help explain why the stock speakers pulled things back where as the A/D/S's don't.

I don't know about the speakers sizes in the GS, but many cars have larger drivers in the rear so they play a little lower and louder and that is where much of the midbass would be coming from on the stock system, which could be the problem stevie was running into.

Stevie, what kind of Vifa setup are you using? I'm using the XT-25 tweeters and really like them.

 

Kyle Harty - Great point about the distortion in the stock speakers pulling the sound rearward and that is gone with the ADS's. Originally I was going to upgrade the speakers and hope that held me but I am coming around to talking myself into an outboard amp. The GS has four inch paper drivers in a ported plastic enclosure in the lower area of both front and rear doors with a tweeter up high in the front door. The dyns and the ADS's are both 6.5 inch drivers and the difference in bass is hard to believe without experiencing it. I guess you can design the heck out of an enclosure but there is nothing like a bigger diaphragm to move air.

I have also read good things about the Vifa speakers, seem like you guys really like them and they are well constructed. The ADS's looked pretty well built but not up to the dyn standards. Still of the opinion that anything is an improvement over stock with good speakers just that much better.

 

Ron,

Welcome to the world of rear fill acoustics. While some people at competitions are always saying "front speakers only", rear fill does indeed make a difference. Take a good high end audio (home) installation, or for that matter, a real stadium or live performance. Yes, the performers are out in front, and in a good home audio installation, the speakers are also up front. But then consider the acoustics of the following...

1. The concert hall. People are performing up in front and the soundwaves are distributed at a fairly even dispersion. That is, there's no wierd things that a speaker has to do...just point at the audience and be done with it. Take a sound meter and point it to the rear of the concert hall. Guess what...you'll get a reading due to the reflected sound from the walls, people, seats, etc. Rear fill.

2. Home audio system, properly set up. Take two speakers up in front, aim properly at the person. Although the speakers are up front, there is rear fill going on due to the reflections in the room. If a person needs evidence of this, take the trusty old sound meter and point it at the rear of the room.

3. Here's the exception. A anechoic room with all the sound deadening material. No echos or acoustic reflections at all. Take two speakers and aim them directly at you, properly setup. Result? It will sound "dry". This is a good simulation of no rear fill.

4. The automotive enviroment. Here you have speakers that aren't pointed at you directly (especially in the GS). The soundwaves have to do some pretty serious contortions to reach the persons ears. Take the front speakers...they're mounted down low, right near the knees. Plus the angle of the speakers will be varied due to the seating position, height of driver, etc, and the speakers aren't pointed or properly angled at the driver or the passenger. The first surface that a soundwave will encounter (for the midwoofers) is the center console, down low. Then it will bounce back off the doors and then will eventually reach the persons ears. BUT, since there are seats in the way, the person will not hear anything from the rear. By the time the sound reflects, it's so minimal that the final result will sound "dry".

Think of the front half of the car as it's own semi enclosure. The front seatbacks would loosely define the rear of the enclosure, while the side of the doors and the front window would define the rest of the "enclosure". Then think of the rear section of the car as another enclosure of sorts. The seats (or in this case, seatbacks of the front seats) act as a barrier.

If you took out the front seats and sat in the rear seats, with the ideal position of speaker placement, then all you would really need are the front set of speakers. This was done with Kirk Perry's Pontiac Lemans at an IASCA event. He took out the front seats and basically duplicated the acoustical enviroment of a high end home demo room. No rear fill speakers (but there were rear fill acoustics), worked beautifully. BUT, once when you put in the seats you lose quite a bit.

Now lets go back to the GS enviroment, or for that matter, any sedan type enviroment. Your ears are listening for the rear fill that is present in pretty much any natural enviroment. If it doesn't pick it up, then it'll sound "dry". In other words, the front section of the car has music going through it while the rear section (back seat area) has almost nothing. Perhaps the ear is waiting for a psychological and natural enviroment response? That's my best guess.

While there are purists that bow up and down to front stage only, I have yet to hear it be properly implemented in any car, with the exception of Kirk Perry's Lemans. I've listened to a couple of front stage only demo vehicles and they were LACKING to say the least. Two demo vehicles immediately come to mind. Sony's XES system, a 15,000 dollar + setup, had front stage only. Although the dynamics were impressive, the acoustics sounded "dry". The other demo vehicle, a BMW325i was from McIntosh. Mc amps, processors, head unit, etc. Once again, front stage only. How did it sound? Due to the Mc speakers, it sounded "warm" and due to the fact it had no rear fill, it, yes, sounded dry.

Rear fill has to be used CAREFULLY. As Kyle mentions, it's very easy to pull the stage back to the rear, and you don't really want that. Just have enough going on the rear section to barely hear it, just like the acoustics in a concert hall or properly setup home audio system.

I could almost write another book on this topic alone!

Percy

 

Percy - Digesting your post but I can vouch for the fact that something made a difference when I replaced the rear door speakers. I can't figure out whether to post it as a subtle difference or a dramatic difference but putting the ADS's in the rear doors really seems to have made the dyns come alive. When I set the fader to full rear however, these things sound disgusting by themselves, especially from the front seat. Probably not the speaker but that ankle aiming position. So why not move the rear speakers to the rear deck? Isn't this more common practice anyway? I hope this doesn't consume me too much but for anyone with a GS, get rid of the stock shocks and upgrade the speakers as soon as possible. Both make the car much more enjoyable and get near that area where you could be happy with this vehicle for a very long time. I wish I could have thought of a better way to post this but this issue is very strange to me but the effect of getting rid of the stock speakers in the rear doors is really worth it. If anyone here has just replaced the front door speakers, you owe it to yourself to upgrade the rear door speakers. Hope I don't drive myself crazy when I upgrade the sub but for now, this is great fun. And if I haven't mentioned it lately, if you are getting the itch to upgrade your system and don'e have THE BOOK, do yourself a favor and contact Percy.

 

Yes, "The Book" is very informative and anyone trying to learn and install audio systems in their car should get it. I kind of wish there will be a sequel (maybe another book?) on the amp modifications from the last chapter tho.

 

Percy - While what you say makes a lot of sense, and I agree with you, I think there is something else happening here as well.

I hear the rear speakers filling in the lower midbass region that is lacking when you play the front speakers on their own (with the sub, of course). You get back the definition of bass notes and the warmth of male voice when you dial the rear speakers in.
I'm guessing that there is a standing wave cancellation due to the length of the cabin front to back.
Just a theory, of course.

Steveie

 

Kyle - I'm using the Vifa polyprop coaxial 5 inch in the plastic basket. I'm not sure what the number is - I think it's an OEM product, as I haven't seen it in any catalogues. I got it free through one of my contacts in the trade.

For the tweets I have a pair of Audax 1 inch neodymium titanium drivers. It's the home version of what Audax uses in its car component sets. Quite nice, although I had to cut and sand it to size to get it into the GS tweeter pod. It's not my ideal tweeter (the car version without the short horn would be better), but it will do for the time being. I'm crossing over at 2.5k.

Considering how cheap the bits were, it sounds OK. I have a really nice sound stage with everything, including the bass, coming from the middle of the windscreen.

The coaxials will eventually find their way into the rears when I eventually decided what I would like to fit permanently up front. I haven't made my mind up yet. Dynaudios are out. I'm not made of money like most people here-

I haven't heard the Vifa XT tweets personally, but they have a really good reputation. I think they are being used in a lot of high end speaker systems like the Krell. They will certainly sound better than any mini neodymium type because they have a rear chamber. You should be able to cross them over at 2k no problem.

Unfortunately, tweeter choice is a bit restricted with the little pod on the GS.

Stevie

 

That's a pretty good theory. I'll have to hook up my B&K analyzer to see what's going on back there. Add that to the stuff I mentioned before and it makes a more complete picture of what's going on. Didn't think of the cancellation...and it should have been obvious.

Percy

 

Hey Percy, when you do reply could you also address what hooking the rear door speakers up reverse did in this whole scheme of things? The physics of a standing wave being generated at anklet height in the rear destructively (or constructively) combining with that from the front speakers is taxing my poor gray matter. At least I feel better that I wasn't just imagining things about the effect of upgrading the rear door speakers. The effect is not straightforward but I am just amazed every time I drive the car how the dyns have "woken up".

stevie - Don't think I am made of money but I understand about the cost of the dyns. But I just had to try them. I am very sure that there are a lot of reasonably priced good speakers out there (in relation to the stock speakers I can't believe there are too many aftermarket speakers that are worse). Really wanted a full range for the back which lead to the ADS's. Dyn for the sub replacement was due to the fact that dyn has no problem going free air and there are very few subs that seem to be happy with that. This is certainly more modification to a car audio system than I have done in a long while (not to mention the fact that I am getting a whole lot better results) and for now, I am just enjoying the heck out of how good things can sound. Sure dims any regret I had over not getting ML.

 

kyle/stevie,

know of any good place for Vifa speakers?

i checked with partsexpress.com but they told me the 5" woofers they carry are for home speakers..