Date: Sun, 7 Apr 2002 12:29:27 -0400
Reply-To: Gary McEachern <glmce@HOTMAIL.COM>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: Gary McEachern <glmce@HOTMAIL.COM>
Subject: Re: Upgraded speakers? (Long)
Content-Type: text/plain; format=flowed
Ben
As a background, my comments come from both personal experience and more
than 20 year experience in the car and home hi-fi audio industry providing
repair/technical/installation support to dealers and end-users.
The larger 5x7 Boston speakers retrofitted in the back of your vehicle have
the ability to produce deep bass at a higher volume levels without
distortion as compared to the OEM or 4" Pioneer speakers you retrofitted
into the front speaker locations.
General information about speakers:
* In order to produce deep bass at mid-high power levels you need to be able
to move air!
* To create "flat" frequency response, it is necessary to move 4 times the
amount of air every time the frequency is reduced by 1/2!
For example:
At 1000hz (midrange) (1/128") +/-.008"
At 500hz (lower midrange) (1/64") +/-.016"
At 250hz (upper midbass) (1/32") +/-.032"
At 125hz (midbass) (1/16") +/-.062"
At 63hz (bass) (1/8") +/-.125"
At 32hz (deep bass,subwoofer) (1/4") +/-.250"
* Smaller speakers cannot move the same amount of air that larger
speakers can due to the smaller physical size of the cone(area) and linear
cone excursion (undistorted linear/in-out movement).
* Excursion is a result of the effective voice coil length and the
compliance(freedom of movement) of the speaker.
* Smaller 4" speakers can produce midbass, but not bass at higher volume
levels. Typical effective voice coil lemgth of 4" speaker is +/- 1/16"
(midbass) 1/4" voice coil length)
* Larger "woofers" often have 1/2" -1" voice coil length to allow for longer
cone movement without distortion.
* Many OEM car stereo receivers have intentionally limited low frequency
bass output based on the smaller less compliant OEM speakers installed in
the vehicle (cutt off bass frequency below 100-200 Hz to prevent distortion
and damage at higher volume levels).
* Aftermaret car radios in most cases don't limit bass frequency to
accomodate the limitations of the speakers.
Comments:
Vanagon speakers (3" front and 2" rear) cannot produce deep bass due to
small size and stiff compliance!
* The supplied Blaupunkt radio has low power and limited bass response to
prevent damage to speakers.
* Replacement aftermarket radios used with mid-high power amplifiers will
overdrive OEM size/style speakers at mid-high volume levels primarily due to
bass content.
Suggestions:
* Installation of larger/more compliant speakers will handle bass better at
mid/high levels.
* When larger/more compliant speakers cannot be used, a crossover with the
capability of blocking the deep bass to the smaller F/R speakers should be
used to prevent crackling distortion of the speaker at mid-high volume
levels.
* A subwoofer should be installed when mid/high volume deep bass is desires
particularly when front and rear speakers cannot produce bass without
distortion.
* Simpler/less expensive "Passive" crossovers with capacitors and/or coils
can be used to block bass or high frequency to speakers when component
amplifiers and/or electronic crossovers are not used.
In my van I currently use:
4" 2 way aftermarket speakers up front with the stock VW "pod" speakers in
the rear (for fill only) with a single 8" subwoofer in a cabinet under the
rear seat. I have a bridgeable 6 ch/50WRMS amplifier used in 4ch/50W,
1ch/100W mode.
I also use a 4 channel-in / 5(6) channel-out electronic crossover that
allows me to take the F/R outputs from the radio and crossover(block) the
bass below 150hz to the front and rear speakers and send the combined F/R
bass information (20-150Hz) to the single 8" subwoofer.
Simplest solution:
I'd suggest you install a 200 micro-farad/25V non polarized capacitor in
series with each fronyt Pioneer speaker (assuming they are not damaged) to
reduce low bass input to the speakers. This, I expect, should
reduce/eliminate the crackling sound you get from these speakers.
I hope this information is helpful.
Gary
----Original Message Follows----
From: Ben McCafferty <ben@KBMC.NET>
Reply-To: Ben McCafferty <ben@KBMC.NET>
To: vanagon@GERRY.VANAGON.COM
Subject: Stereo experts? was: Re: who has upgraded their front vanagon
door SPEAKERS??
Date: Sat, 6 Apr 2002 12:13:31 -0700
OK, while we're on the stereo topic....
PO installed a Clarion CD player in my westy, with Boston Acoustics
speakers. They are in the back, and with the fader all the way to the rear,
the sound is clear at any volume level.
My front speakers were stock, and they crackled pretty bad, so I replaced
them with some Pioneers that I had laying around. If I put all sound to the
rear, it's crystal clear at any volume setting. If I put it 50/50
front/rear or all to the front, the Pioneers crackle at louder volume
settings, but not at lower ones. Maybe the Pioneers are just blown, but I
didn't think they were. Here's the relevant info:
Clarion BD216 CD/tuner, 45Wx4 max, 17Wx4 normal, 4-8 Ohms allowable for the
speakers.
Boston Acoustics RC820 system, with two 5x7" RC820 woofers, and two Neo 3R
Tweeters. There is a crossover on each side (820X from BA). The crossover
has an input from the stereo, then an output to woofer, tweeter and amb.tw.
(ambient tweeter?). The amb tw socket is not in use. The system calls for
a recommended amp of 20-275W, 4 Ohms.
Pioneer 10cm 2-way, model TS-A1090. 50W max, 10W nom. (nominal?) power, 4
Ohms.
Is this simpler than I think, and the Pioneers are just blown, or is
something mismatched? If the Pioneers are blown, what would be the best way
to take advantage of the Clarion and BA stuff, since it's new? Can I wire
my Mac DVD in for surround sound in the westy (just kidding, but it would be
sweet!....)
Thanks for any thoughts.
bmc :)
"Faith will move mountains, but you'd better bring a shovel...."
> From: Ben huot <huotx@VIDEOTRON.CA>
> Reply-To: Ben huot <huotx@VIDEOTRON.CA>
> Date: Sat, 6 Apr 2002 02:44:27 -0500
> To: vanagon@GERRY.VANAGON.COM
> Subject: Re: who has upgraded their front vanagon door SPEAKERS??
>
> I have a kick ass system...
> http://pages.infinit.net/eurokit/westy_modifications.htm
>
> And i speak what ever i can, indian for now....it's late.
>
> Lol, Ben
>
Gary McEachern, Reading Ma.
'90 Westy
'87GL Wolfy Weekender SubaVanagon
'87 Syncro
'91 Subaru Legacy Sedan
'93 Subaru Legacy Wagon
'76 Camper
'75 Spitfire
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