chuck911

How'd you measure impedance? Do you have a 'scope?

lunarx

Just static impedence, with an ohm meter.
I know that is almost pointless, as its dynamic impedence, that really matters. But thats more involved to measure and plot.

chuck911

Right. You measured DC resistance, not impedance, which applies to AC and varies with frequency. Sometimes a driver with benign nominal resistance has really hard to drive imedance swings at certain frequencies. If you can get a part number for your drivers then just maybe you might get lucky and find this on-line. But really, based on all my experience, until and unless these things get way out of line they just don't matter all that much. There's no shortage of geeky audiophiles eager to take me to task for that, but actual listening experience is what counts for me. Its nice to know this stuff before you pay to play, but honestly you never really know until you do play. And then you have to go by results not theory. Which you are doing. Keep up the good work!

77tony

From what I can see with the wheels on, the rear fender liners cover approx 75% of the wells. Most of what can be covered is closer to the driver/passenger which is ideal. When finished with up front, will pull the rear wheels and see if we can quiet things down a bit. If we can quiet things down some, would like to do lunarx's mod without having to mess with the sub/amp. T

See U n RearView

Thanks Lunarx for the detailed instructions. I was in a 911 and am still debating between which system to go for. In the 911 S with BOSE, I had my left knee resting against the door and the speaker area, where I guess was the mid was vibrating terribly.

Chuck911 hit the nail on the head. Curious if strengthening the area around the mids, and possibly using some sheet sound deadening material would help?

I have listened to the Burmester, and sounded clear but similar songs listened to on the Bose sounded so high pitched and tinny that Upgrading the Bose may be the best route... I also have been told that there is a lack of adjustability on the Burmester... thoughts...

lunarx

What you felt was the door woofer vibrating.
There is also a mid in the door, but you won't feel it vibrating.
I would have to imagine the Burmester Door Woofer would also vibrate.
Its the same physics involved.
It is something that needs to get fixed, but open baffle woofers, in a door, are always a problem.

Anyone with the opportunity to get Burmester should take that route.
This upgrade is for those of us stuck with Bose and trying to undo some of the corner cutting, that is holding it back.
I think it sounds much better now, with this upgrade and settings.
I would still like to upgrade the sub, but I could live with it, as is, now.

BTW - I unplugged the Sub Amp (to confirm it was a sub amp) and there was still a lot of bass in the system (from the door woofers).
So that sub is handling some very low frequencies, which makes me optimistic about swapping in the Burmester Sub and a booster amp.

chuck911

When I said vibration control in audio is HUGE, I wasn't just talking speakers. But speakers are the obvious one, pretty much everyone can understand, so we start there.

Yes the more you can reinforce speaker mounting areas the better. Probably your best bet with door panels is carbon fiber. First figure out what resins will bond to the door material. Then remove the door panel, mask it off, brush on resin, lay on carbon fiber, brush on more resin, and repeat a couple times near the mounting area. You could do the same for a lot less money with fiberglass, but carbon fiber has tremendously greater natural vibration control properties.

What'll really amaze you though is how much better electronic components can sound. This one was hard to believe until I tried it. Took some of my BDR Cones to an audio installer. (These are by far the single best most cost-effective tweak on the market) http://www.musicdirect.com/p-383-bdr-cones.aspx He had one of those demo rooms with amps and head units on a wall. We loosened up some mounting screws enough to place three Cones between the amp and the mounting board, and tightened everything down again. He couldn't believe it- partly because it sounded so much better than any tweak he'd ever tried, partly because you wouldn't think it would do anything at all.

Its really hard doing something like this in a Porsche. Space is just too tight. But the general principle applies. Anything you can do to make your system mounting closer to granite than plastic will help. Like carbon fiber, it doesn't have to be heavy. Just as long as its plenty stiff and non-resonant it'll do just fine.

lunarx

Thats Crazy

Noah Fect

There's gotta be an equivalent to Poe's Law for this sort of thing...

MJBird993

Thanks to Lunar for the photos, because I clicked on the link and it didn't explain it at all. I still don't get it: you're saying that if you place these cones between the amplifier and whatever it's sitting on, that it will improve the sound quality of a solid circuit device that theoretically doesn't actually move during operation and shouldn't be affected by movement anyway? Seriously?

Do I have to use my Monster cables as well?

chuck911

Yes. I know. That was my initial reaction as well. I'm a good sensible man of science and this is pure quackery. Plus I'm a good sensible audiophile raised on decades of Julian Hirsch Stereo Review who knows all you need is some good fat lamp cord and you're all set. No way I am throwing away even $20 on such nonsense.

Then someone (audiophile, another kook) told me his CD player sounds better sandwiched between two phone books. Equally silly, but free. So I tried it.

Took the better part of an evening to be sure, but yes indeed, it did help. Marginally. I'd forgive you rolling your eyes. But there was no denying it did help.

Now at this point I would love to be able to tell you I did a bunch of research into why (which I did) and came up with some answers (which I didn't, only theories) and proceeded to logically select the ideal vibration control solutions. Which definitely did not happen.

What happened instead was I got lucky. Another guy recommended BDR Cones, I tried them, and was flabbergasted. Went crazy putting them under everything. Carried them around making a pest of myself everywhere I went.

This taught me more about people and music than Cones. For example, there are lots of guys who are perfectly capable of denying their own experience until and unless they have what they consider to be a sensible theory explaining why they should feel that way. (Ring any bells?) On the other hand there are people who don't care why or what they just want the music. One couple, the guy had me going back and forth between the two Cones and no Cones, peppering me with questions, straining and striving to get his mind around it. After the better part of an hour he calls out to his wife who had been puttering around in the kitchen the whole time. Without even coming in the room she says I don't know what you're doing but whatever it is his voice is a lot more present and clear with the one you were using before!

So I know it works. Beyond a doubt. You want to try and figure out why? Be my guest.

Noah Fect

I've lived long enough to know not to trust my own brain that much. That's why I'm an A/B/X or GTFO kind of guy.

An interesting test would be to record the PCM data from the CD player's S/PDIF or Toslink output with and without the cones, and see if the cross spectrum shows any differences. The streams probably won't be bit-identical because of the way CD error correction works (although that shouldn't be a problem with DVD-A or SACD) but you can't fool Fourier.

chuck911

I'm sorry to hear that, Noah. What is it then? Alzheimer's?

Seriously though, it would explain why you missed that in the story above, the guy's wife was the unwitting subject in an A/B/X test. She not only picked the Cones, she could tell them apart and describe their salient characteristics and differences between them.

But she was young, brain not all shot to hell. How much longer they give you?

clutchplate

Fortunately these types of tests are recordable which allow you to go back a few days later and see if you can really tell the differences in a blind shootout. They can also be posted online which few people seem willing to do. When I had more time on my hands I did several blind tests with cables, convertors, pre-amps etc. and could always pick out components. I found the differences between expensive cables and cheap home depot dryer cords however to be so miniscule that I stopped being concerned about them. I have some exotic cords in my recording studio but rarely reach for them over standard grade Mogamis. I do try to keep an open mind about these things, perhaps someone could post some cone/non cone audio files.

chuck911

Michael Fremer has been doing this for years. He makes recordings of records played back with different phono cartridges. Carries them around with him, to shows and stuff, as a convenient way of letting people compare. Here's one story I googled up in nothing flat http://www.analogplanet.com/content/...udible-results

But here's the thing. The reason its worth doing in this case: comparing phono cartridges, especially the higher end models, is something only a tiny percentage of audiophiles will ever be able to do. Recordings like his are really the only chance for normal folks. But anyone can plop down $60 for some Cones, and lots will be able to find a shop to try them out for free.

But when you said, "I found the differences between expensive cables and cheap home depot dryer cords however to be so miniscule that I stopped being concerned about them." That really concerns me. Because, you're making recordings.

I had a party one time, playing music for a bunch of people, about half audiophile buds, half Porsche friends. Caelin Gabriel http://www.6moons.com/industryfeatur...in/caelin.html was there and demo'd some power cords for us. Every single person there not only easily heard the differences when we changed cords, but most of them (and all the Porsche people) were really surprised at how easy it was and how big the differences were. I've done similar comparisons with lots of people and components over the years. I've even had a couple people with hearing aids who were shocked to realize they too could hear these things.

In fact the ability to hear these things is so common I'm inclined to believe that if you're not getting it, its not your ears, its your system.

This can happen. I had a friend, lifelong audiophile, half his home devoted to his hobby. Several times he brought over interconnects he had made, believing he could do 'just as good' as the pros like Caelin. Every time you could see the shock and disbelief on his face. As he told me nearly every time, when he tried them at home they sounded nearly the same. But on my system it was easy to hear the pro cable sounded a lot better. Wider, deeper soundstage. Greater palpable presence. More liquid, with greater separation between instruments and a blacker background. http://www.stereophile.com/content/s...ssary-glossary

If you've done like he did and built yourself a system that can't resolve the difference between dryer cord and even an old used Synergistic Research http://www.stereophile.com/content/s...-john-atkinson Master Coupler power cord, well you've got your work cut out for you. But trust me, it can be done.