Back to audio (subwoofer, specifically)...
03-01-2005, 09:44 PM
#31
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Randy, - you did not understand my point about Pressure enviroment... The car is not a free air setup, it is at a minumum a dual enclosure enviroment. i.e... the box, the listening area... some cars will have a box in a trunk (that's 2 enclosures) plus the listening area - 3.
We do a lot of cars with a "Free air" set up and they have awesome bass, sound and output.
The reason we can "cheat" the system, if you will is because of the transfer function of the vehicle. The amount of "gain" at low frequencies that the car "adds" is staggering, and the smaller the car the larger the gain.
If you do not believe that, move your Maggies in to a small closet in your home and get in there, close the door and listen to them in there.
You will blown out by the increase of bass and SPL because of the "cabin Gain" or what is really the Transfer Function of the Enviroment, i.e... the closet or small car.
This is all VERY well know and understood in car audio and sound re-enforcment circles.
Remember the Trunk is an enclosure... the smugglers box is an enclosure... the inside of the car (where you are sitting) is Also an enclosure and all of these effect the frequency response of any speaker in a car - in a good way most of the time.
We do a lot of cars with a "Free air" set up and they have awesome bass, sound and output.
The reason we can "cheat" the system, if you will is because of the transfer function of the vehicle. The amount of "gain" at low frequencies that the car "adds" is staggering, and the smaller the car the larger the gain.
If you do not believe that, move your Maggies in to a small closet in your home and get in there, close the door and listen to them in there.
You will blown out by the increase of bass and SPL because of the "cabin Gain" or what is really the Transfer Function of the Enviroment, i.e... the closet or small car.
This is all VERY well know and understood in car audio and sound re-enforcment circles.
Remember the Trunk is an enclosure... the smugglers box is an enclosure... the inside of the car (where you are sitting) is Also an enclosure and all of these effect the frequency response of any speaker in a car - in a good way most of the time.
Last edited by Eric Holdaway; 03-01-2005 at 10:03 PM.
03-01-2005, 09:51 PM
#32
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Originally Posted by imcarthur
Randy is on track here folks. A bigass driver (or several) driving forward or backward into an unknown and undampened environment will yield unpredictable (in a bad way) results.
Ian
Ian
Ian,
Larger drivers are INHERENTLY LOWER distortion than smaller drivers.
Larger drivers will always sound better than comparable smaller drivers. Larger driver will be MUCH more expensive, true, but they will sound better.
The hood enclosure of a 911 would not be "unknown." You may think that it will be underdamped because of it's size. You are thinking in Home audio - Home enviroment thinking, but because of the transfer function of the smugglers box, the hood area and the listening areas pressure response, you regain that control with a VERY low resonance frequency (VERY GOOD for sound) and a nice shallow rool off on the deep bass, meaning that the subs will go very low with articluation and impact.
03-01-2005, 10:08 PM
#34
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I would perfer to go with the doors or the rear box that I talked about my self, but I would not shy away from the front "Free air" setup if they do not have A/C. Most of these cars have A/C, so it's a bit academic.
03-02-2005, 01:37 PM
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Here is a couple of picture of the Kick panel install that is easier to see.
Going back to the "Free air" thing. In my job as the product reviewer for Car Audio & Electronics magazine, I get to test and play with a LOT of subwoofers.
Many of those subs, even the ones that "Require" small boxes, will work very well in a cars Free air. I promise!
Going back to the "Free air" thing. In my job as the product reviewer for Car Audio & Electronics magazine, I get to test and play with a LOT of subwoofers.
Many of those subs, even the ones that "Require" small boxes, will work very well in a cars Free air. I promise!
03-02-2005, 02:41 PM
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Phone call today from installer:
"Hey, we just finished putting out your car. Those tops really go up fast, don't they? You sure you want that little woofer box under the driver's seat? And where the hell is the battery? How do you open the trunk? No, not the front, the back, where the battery is?"
He was joking about the fire, and I set him straight on box location under the passenger seat, the battery location, & the hood / trunk release levers.
"Hey, we just finished putting out your car. Those tops really go up fast, don't they? You sure you want that little woofer box under the driver's seat? And where the hell is the battery? How do you open the trunk? No, not the front, the back, where the battery is?"
He was joking about the fire, and I set him straight on box location under the passenger seat, the battery location, & the hood / trunk release levers.
03-02-2005, 04:31 PM
#37
Anyone planning to use a woofer in free air or a larger box or any non-std. configuration would be well advised to get the formulas and/or calculations from a speaker building site or a book and run the numbers. Note that the entire trunk won't really be an acoustic suspension design - instead the air leaks will let it act like a ported design to some extent.
- I have no financial interest in any of this, BTW - I'm a scientist and make no $$ from any audio equipment you buy or don't buy.
- I have no financial interest in any of this, BTW - I'm a scientist and make no $$ from any audio equipment you buy or don't buy.
03-02-2005, 05:12 PM
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Randy,
You sound like such a Doubting Thomas!
You have to look at the Cabin Gain/Transfer Function...
How can you figure out the Cabin Gain?
We have found that if you measure the longest area of the car, then double it. This is the wavelength where cabing gain will kick in.
Because we are looking at a compound effect, we can say that in an ideal world an increase of 12db per octave would occure, but we can't, as you ahve said the car's aren't sealed, as a rule of thumb we usually work around the 7 to 10db per octave mark.
Best bet is to meaure the transfer function of the car, this will indicate lot's of helpful things like cabin gain and the resonant freq of the vehicle
Now if you want to measure the Transfer Function of your car then you can, put any speaker (Sub would be best as we are talking about bass) with a given bandwidth in free field (Non-reflective) and measure it Freguency response.
Then, put the same speaker in the location you want inside the vehicle, measure it again.
Compare both curves and the difference between the two give you the transfer function that you can plug into your T&S model that you are talking about.
If you are a home audio guy, I know all this will sound a bit radical, but it is not for car audio.
Break out your text book and think of the car as a "Bandpass" enclosure. Because you are coupling more air mass, via a better acoustic impedence match in the car, you are getting a hugh riase in low freq out put and less reliance on the specific enclosure... back to the acoustic impedence match... because you are really looking a a semi - band pass enviroment, all that extra air mass on the front of the cone adds control to the subwoofer.... that is why you can get away with using a Free-air arrangement.
I'm not selling any free-air 911 stuff here either. I am just talking about what can be done, what can work in these cars and sound good.
Yes, I am in the industry, and have owned my store since 1980, I write product reviews for CA&E magazine and have won 17 IASCA World championships for sound quality. Well... 15 for sound and 2 for SPL, but I am not all that proud of the SPL ones as I hate that crap.
I love 911's. The black one on our site was our show car for many, many years.
You sound like such a Doubting Thomas!
You have to look at the Cabin Gain/Transfer Function...
How can you figure out the Cabin Gain?
We have found that if you measure the longest area of the car, then double it. This is the wavelength where cabing gain will kick in.
Because we are looking at a compound effect, we can say that in an ideal world an increase of 12db per octave would occure, but we can't, as you ahve said the car's aren't sealed, as a rule of thumb we usually work around the 7 to 10db per octave mark.
Best bet is to meaure the transfer function of the car, this will indicate lot's of helpful things like cabin gain and the resonant freq of the vehicle
Now if you want to measure the Transfer Function of your car then you can, put any speaker (Sub would be best as we are talking about bass) with a given bandwidth in free field (Non-reflective) and measure it Freguency response.
Then, put the same speaker in the location you want inside the vehicle, measure it again.
Compare both curves and the difference between the two give you the transfer function that you can plug into your T&S model that you are talking about.
If you are a home audio guy, I know all this will sound a bit radical, but it is not for car audio.
Break out your text book and think of the car as a "Bandpass" enclosure. Because you are coupling more air mass, via a better acoustic impedence match in the car, you are getting a hugh riase in low freq out put and less reliance on the specific enclosure... back to the acoustic impedence match... because you are really looking a a semi - band pass enviroment, all that extra air mass on the front of the cone adds control to the subwoofer.... that is why you can get away with using a Free-air arrangement.
I'm not selling any free-air 911 stuff here either. I am just talking about what can be done, what can work in these cars and sound good.
Yes, I am in the industry, and have owned my store since 1980, I write product reviews for CA&E magazine and have won 17 IASCA World championships for sound quality. Well... 15 for sound and 2 for SPL, but I am not all that proud of the SPL ones as I hate that crap.
I love 911's. The black one on our site was our show car for many, many years.
Last edited by Eric Holdaway; 03-02-2005 at 07:36 PM.
03-02-2005, 05:45 PM
#39
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It would be interesting to those of us not looking for a high end setup to hear a report on the 'cheapie, modest' clarion stuff it under the seat model.
Fred, how has it worked out?
Eric, you got any more info on the modified bazookas?
todd
86 coupe
Fred, how has it worked out?
Eric, you got any more info on the modified bazookas?
todd
86 coupe
03-02-2005, 07:38 PM
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Originally Posted by CrossT
Fred, how has it worked out?
Eric, you got any more info on the modified bazookas?
todd
86 coupe
03-02-2005, 10:00 PM
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New setup report...
"WOW" over the old configuration. It's certainly not the twin-15" subs powered by 1000W amps, but it's really much more noticeably better than the old.
Original, as purchased:
Original speakers, rears blown; Blaupunkt New Orleans CD Deck.
Step 1:
Replaced speakers with Infinity Kappa-series speakers, 5.25" fronts, 4" rears. Cost from eBay, approx. $130-140ish for all 4 speakers, delivered (from memory). Improvement, but not night & day.
Step 2:
• Replaced Blaupunkt deck with Nakamichi CD400 deck, 47Wx4, subwoofer controls, pre-outs for everything including the toaster, microwave, etc, aux-in, remote, auto incoming phone mute capability, etc. Conservative (removeable) faceplate design, 4 different amber / green color combos, and something I discovered I REALLY like in the 911... the ability to turn the lighting off completely while the deck's on.
• Installed crossovers that came with the Kappas (no, I didn't have them hooked up, me being an audio-idiot).
• Installed Clarion SRV303 65W RMS 7" powered sub unit under pass. front seat. Fits right under the seat, totally invisible.
At 2300-2500 rpms in 5th on the highway, I can barely hear the engine (stock exhaust) in my Cabrio, with the volume at 36 out of 60. Over 38, and the main speakers begin to mask the sub the way it's set right now. I have the balance slightly to the left, and the fade slightly to the rear.
Since the Nak deck has subwoofer controls, I can completely shut the Clarion off, for comparative purposes. The Nak deck does sound better than the Blau by itself, but I was able to nearly duplicate the old sound before the deck swap, then turn the sub on - welcome home, Mr. Bass. No homecoming parade or anything, but he's definitely back in town. In my SHO, with the Pioneer 9-band EQ, it'd be like listening to the 1st 3 bands all the way down, then suddenly turning them on the for the first time - it's that noticeable. Again, not overwhelming, and I would love to have better control than Bass / Mid / Treble / Sub controls like with the EQ, but it's very nice, compared to the old setup. If funds were not an object, I wouldn't mind hearing a duplicate system with a 2nd Clarion unit under the driver's seat, if it'd fit. I didn't want to put it there because of the engine computer, but for sound placement, it'd be better for the driver on the left side I think, because the right side's speakers are much more noticeable anyway.
• Nakamichi CD400, eBay or Amazon (same seller, Jonny641 or something like that), about $290 delivered new.
• Clarion SRV303, list is $250, eBay ~$200 delivered new.
• Installation, my installer's really good by me, but I'd guess ~$150 or so to have a typical shop install all the components I'd gotten. Deck-only installs are usually around $50 he told me.
All told the deck, speakers, subwoofer, and installation would run <$900 or so.
I was seriously considering just putting the new deck in & seeing how that was; I'm very glad I picked (the Clarion) up. While I know I'll still drive loveing to hear just the engine, I like knowing I have the choice now.
If anybody in the area wants a listen, just give me a hollar.
PS - FWIW, I have 2 different range hearing losses (left & rigth side different), from childhood illness, so the volume's probably better for the average person, and the 4-band controls'll probably be a-ok too.
"WOW" over the old configuration. It's certainly not the twin-15" subs powered by 1000W amps, but it's really much more noticeably better than the old.
Original, as purchased:
Original speakers, rears blown; Blaupunkt New Orleans CD Deck.
Step 1:
Replaced speakers with Infinity Kappa-series speakers, 5.25" fronts, 4" rears. Cost from eBay, approx. $130-140ish for all 4 speakers, delivered (from memory). Improvement, but not night & day.
Step 2:
• Replaced Blaupunkt deck with Nakamichi CD400 deck, 47Wx4, subwoofer controls, pre-outs for everything including the toaster, microwave, etc, aux-in, remote, auto incoming phone mute capability, etc. Conservative (removeable) faceplate design, 4 different amber / green color combos, and something I discovered I REALLY like in the 911... the ability to turn the lighting off completely while the deck's on.
• Installed crossovers that came with the Kappas (no, I didn't have them hooked up, me being an audio-idiot).
• Installed Clarion SRV303 65W RMS 7" powered sub unit under pass. front seat. Fits right under the seat, totally invisible.
At 2300-2500 rpms in 5th on the highway, I can barely hear the engine (stock exhaust) in my Cabrio, with the volume at 36 out of 60. Over 38, and the main speakers begin to mask the sub the way it's set right now. I have the balance slightly to the left, and the fade slightly to the rear.
Since the Nak deck has subwoofer controls, I can completely shut the Clarion off, for comparative purposes. The Nak deck does sound better than the Blau by itself, but I was able to nearly duplicate the old sound before the deck swap, then turn the sub on - welcome home, Mr. Bass. No homecoming parade or anything, but he's definitely back in town. In my SHO, with the Pioneer 9-band EQ, it'd be like listening to the 1st 3 bands all the way down, then suddenly turning them on the for the first time - it's that noticeable. Again, not overwhelming, and I would love to have better control than Bass / Mid / Treble / Sub controls like with the EQ, but it's very nice, compared to the old setup. If funds were not an object, I wouldn't mind hearing a duplicate system with a 2nd Clarion unit under the driver's seat, if it'd fit. I didn't want to put it there because of the engine computer, but for sound placement, it'd be better for the driver on the left side I think, because the right side's speakers are much more noticeable anyway.
• Nakamichi CD400, eBay or Amazon (same seller, Jonny641 or something like that), about $290 delivered new.
• Clarion SRV303, list is $250, eBay ~$200 delivered new.
• Installation, my installer's really good by me, but I'd guess ~$150 or so to have a typical shop install all the components I'd gotten. Deck-only installs are usually around $50 he told me.
All told the deck, speakers, subwoofer, and installation would run <$900 or so.
I was seriously considering just putting the new deck in & seeing how that was; I'm very glad I picked (the Clarion) up. While I know I'll still drive loveing to hear just the engine, I like knowing I have the choice now.
If anybody in the area wants a listen, just give me a hollar.
PS - FWIW, I have 2 different range hearing losses (left & rigth side different), from childhood illness, so the volume's probably better for the average person, and the 4-band controls'll probably be a-ok too.
Last edited by 84_Carrera; 03-02-2005 at 10:18 PM.
03-05-2005, 01:26 PM
#43
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Woohoo! I just put mine in last night. It fit perfectly under the passenger seat with a little room to spare. Pretty impressive for such a small box. It's definitely not something that your going to go thumping around in downtown, but that's not what I was looking for. It will rattle the rear view mirror though. I spent quite a while trying to dial it in with my head unit and mains (Alpine with separate midrange/tweeter in the doors [no rear speakers]). If I turned it up too loud it would get muddy pretty quickly. I also had to limit anything over 80 Hz from going to the sub. If I sent anything over 80 Hz to it, it drown out my mains and sounded very tinny. I have the gain turned up about 1/2 and use the sub controls on my head unit to dial it in. For only $180, it's well worth trying out. And it comes with everything you need to mount it and hook it up. I didn't get to do much driving around with it though because it started raining and I had to run back to the garage. My car is pretty LOUD so it will be a good test when I get to go on a road trip.
03-05-2005, 05:01 PM
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Just curious, as I have an extra pair of new Infinity Kappas in 6 1/2" (bought the wrong front door speakers originally)...
...would the 6 1/2's fit in the rear side panels where the 4's are now (obviously with a little trimming)? Didn't know if this is a common thing or what.
Glad you also liked the SRV303. Like you said, it's not something to thump around town with, but it's enough to give an added dimension that was missing on my setup.
...would the 6 1/2's fit in the rear side panels where the 4's are now (obviously with a little trimming)? Didn't know if this is a common thing or what.
Glad you also liked the SRV303. Like you said, it's not something to thump around town with, but it's enough to give an added dimension that was missing on my setup.
03-07-2005, 04:39 PM
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Originally Posted by 84_Carrera
Just curious, as I have an extra pair of new Infinity Kappas in 6 1/2" (bought the wrong front door speakers originally)...
...would the 6 1/2's fit in the rear side panels where the 4's are now (obviously with a little trimming)? Didn't know if this is a common thing or what.
...would the 6 1/2's fit in the rear side panels where the 4's are now (obviously with a little trimming)? Didn't know if this is a common thing or what.