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why not just wear headphones and stop all the stereo nonsense.
 

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I have heard a lot of bad things about the sound quality (not loudness) of the bazookas. They are okay if you want a lot of thumping, but bad for bass reproduction accuracy.

I see two different small subwoofers being talked about on the forums. The Clarion SRV303 and the Kenwood KSC-WA62RC. Neither, of course, will put out a lot of bass (which can be an issue when the normal speaker volume is high and the top is off), but I have heard that they at least puts out accurate reproduction (well, for their size). I would be interested in a head-to-head comparison, but could not find such a comparison on the web. Maybe two Elise owners who have one or the other installed could get together and compare. (Or one person order both, try both, and return the one they don't like.)

Maybe the footwell version is the way to go. I just don't want to build a subwoofer and find a place for the amp myself (too little free time).
 

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scottyb said:
What HU do you have?
**Correction it's 60watts RMS 70 Peak per channel. I believe the most of any current HU.**

Panasonic CQ-C9800U High Power Car CD Player Digital internal amp, 60 watts RMS x 4


Higher power, in-dash head-end units have three significant implications for OEM designers. The Panasonic head unit offers more real power then many outboard amplifiers. A big impact is the space and heat savings. With the extra space created by getting rid of the heat sinks, OEMs can add better digital signal processors and bigger LCD monitors.

Switching amps allow for more channels in the head unit. Some OEMs are already looking at six channels for in-car-theater, but what about eight or 12 channels? With the horsepower in the DSP, active crossovers can be used to amplify each speaker driver separately while still fitting into a normal, single-DIN package.

The Panasonic uses the Tripath 60 W x 4-channel module, which features a built in DC-DC converter as well as Class T operation. “Class T” is Tripath’s name for their low distortion, full range sophisticated variation of Class D switching amplifier technology which is used by Panasonic and quite a few others, mostly in home theater and large screen TVs. Other vendors for switching amplifier ICs include Texas Instruments, and Apogee and ST.

Class AB amplifiers are by far the most common car amp design. Switching amplifiers (Class D) boast higher efficiency (some approaching 90 percent), produce less heat, and draw less current than traditional Class AB designs. Because they produce much less heat, Class D amplifiers can be housed in a much smaller chassis than a Class AB with the same power output.

For example, Tripath’s newest module is 4 x 100W and would be generating about 400W of heat if it were an AB amplifier. Adding the signal output power and the heat together, it’s pulling 800W from the battery. Changing to a switching amp, that same 800W from the battery can deliver 720W to the speakers, creating a 4 x 180W amplifier without pulling any more power, and only generating 80W of heat. Or in the case of the Tripath module, 400W of audio and about 40Wof heat.

As miniaturization and density increase, satellite radio, communication systems such as on-Star and equivalents, and the hands-free cellphones can be integrated into the head-end unit.
 

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Class D amps will instrinsically produce more distortion than a class A/B amp. Hence, an audiophile will always use a good class A/B. However, the Elise is not the place to worry about audiophile quality sound.
 

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ChrisH said:
. Neither, of course, will put out a lot of bass (which can be an issue when the normal speaker volume is high and the top is off), but I have heard that they at least puts out accurate reproduction (well, for their size)

that "accurate reproduction" is a misnomer... once again, the actual response curve depends entirely on the transfer function of the vehicle and the transfer function is different when the top is on or off... the way a particular enclosure sounds in your living room is totally different from how it will sound in one vehicle and will change for each different vehicle.

the typical vehicle interior acts to provide a natural boost at around 40-70 hz. hatchback vehicles tend to have the most boost (upwards of 10 db at 40hz) and small cockpit vehicles tend to have the least (although still 3-6 db at 40-50 hz). when you pull the top off of the vehicle, two things happen: first, the 40 hz boost disappears and second, the woofer excursion increases for lower frequencies. Both of these effects happen for the same reason; a woofer has a normal excursion (how far a woofer moves in/out vs frequency) any woofer has more excursion as the frequency gets lower and correspondingly more output as excursion increases, right down to the tuning frequency of the box. below the tuning frequency, the excursion increases rapidly with little increase in output. the reason for this is because the vehicle interior presents a certain amount of compression against the woofer face for particular frequencies and this pressure tends to resist movement of the woofer. when the top is off, the woofer is essentially seeing an infinite interior space and therefore does not naturally limit excursion of the woofer.

This means the obvious: when the top is off, the woofer moves further out, but without any vehicle backpressure to resist that movement, the woofer will keep pushing further out at lower frequencies until it reaches its maximum excursion (xmax). unfortunately, there is no way to design an enclosure that will perform properly under top on and top off conditions but what can be done is to use active equalization to alter the signal when the top is off. the ideal enclosure would use a high xmax woofer at a slightly larger than normal enclosure and a baffle 1.5 inches in front of the woofer face to provide some control. alternatley, if the space existed the woofer could be faced upwards as well.

The active eq would preform two main functions: first, it would provide subsonic rolloff filtering below the tuning frequency of the enclosure. this would essentially filter off all sound below ~30 hz which you would normally never hear since the enclosure is massively inefficient at those frequencies as well as control the high woofer excursion at and below the tuning frequencies. this allows a boost at the tuning frequency of an additional 3-6 db at 40 hz which makes a huge difference. the second function would be to provide 2 equalization curves from 40-100 hz for top off and on. both curves would be set using an RTA to provide even response with a slight bump at 40 hz ( to provide reinforcement for bass kick drums and such... perfect for rock music) you would then simply change the eq setting when you take the top off.
 

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Some links in regards to the Clarion and Kenwood units:
Clarion
Kenwood

Or, how about tactile sound:
http://www.partsexpress.com/webpage.cfm?&DID=7&WebPage_ID=3
http://www.audioenz.co.nz/2003/bass-shaker.shtml

http://www.thebuttkicker.com/LFE_home.html
http://www.bananas.com/productlist.asp/vendorid_130/searchstring_ButtKicker

This is probably the best of the tactile units (just based on reading up on these on the web tonight). Note, in the second link that describes Clark's approach, competitive unit A is the Aura Bass Shaker, and B is the Buttkicker. In a car application, particularly with the Elise's rigid seats with little padding, I wonder if the Clark unit was installed if one would even need a subwoofer (and hence not have to worry about the top on/off problem in subwoofer response). Clark says that this augments, not replaces, a subwoofer, but in a low fidelity audio environment like the Elise, it may not matter much. The new TST239 unit is about $100 each.
http://www.clarksynthesis.com/
http://www.clarksynthesis.com/whatis.php
http://www.bigbangelectronics.com/tactile_sound/testimonials.asp
How much space do we have between the bottom of the seat and the floor? The unit is 8 inches wide and 2.25 inches tall.
 

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ChrisH said:
Or, how about tactile sound:
http://www.partsexpress.com/webpage.cfm?&DID=7&WebPage_ID=3
http://www.audioenz.co.nz/2003/bass-shaker.shtml

http://www.thebuttkicker.com/LFE_home.html
http://www.bananas.com/productlist.asp/vendorid_130/searchstring_ButtKicker

This is probably the best of the tactile units (just based on reading up on these on the web tonight). Note, in the second link that describes Clark's approach, competitive unit A is the Aura Bass Shaker, and B is the Buttkicker. In a car application, particularly with the Elise's rigid seats with little padding, I wonder if the Clark unit was installed if one would even need a subwoofer (and hence not have to worry about the top on/off problem in subwoofer response). Clark says that this augments, not replaces, a subwoofer, but in a low fidelity audio environment like the Elise, it may not matter much. The new TST239 unit is about $100 each.
http://www.clarksynthesis.com/
http://www.clarksynthesis.com/whatis.php
http://www.bigbangelectronics.com/tactile_sound/testimonials.asp
How much space do we have between the bottom of the seat and the floor? The unit is 8 inches wide and 2.25 inches tall.

ahhh.. hold your toungue! (just kidding) seriously, though.. the whole tactile sound thing is a waste of money... i remember installing them under the seats in an alfa years ago when they were new and aside from getting the girls in the passenger seat excited, they serve absolutely no purpose. all they really do is to vibrate the surface they are mounted to the same way the compression wave from a woofer would. but they do not make any sound so you still need a woofer.

besides, girls get turned on enough just being in a lotus... and i like my passenger seat dry :)
 

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>>>hhh.. hold your toungue! (just kidding) seriously, though.. the whole tactile sound thing is a waste of money... i remember installing them under the seats in an alfa years ago when they were new and aside from getting the girls in the passenger seat excited, they serve absolutely no purpose. all they really do is to vibrate the surface they are mounted to the same way the compression wave from a woofer would. but they do not make any sound so you still need a woofer.<<<

I've done very careful A/B listening tests with properly set up tactiles. Done right as an augment, and you can't tell the difference from "real" bass. And they are totally nonboomy and unaffected by acoustics issues. I'll see if I can find an old review on them in a nice car install but the writer was flabbergasted at the quality and quantity of high quality bass that could be enjoyed. Note that convertibles with a soft top cannot benefit from the cavity effect to any degree so bass tends to seem weak.

My old home theater had a series of Buttkickers with 4000 watts behind them. First domestic use in the US. They were floor joist mounted under a huge room and you could knock things over in the room with them. Such as knickknacks on coffee tables and so forth. Combined with the 8000 watt 8 foot tall custom subwoofer rig it was pretty impressive. It could do over 135 dB at the couch. About 0.3% distortion at 25 hz at over 120 dB = none, essentially as bass is pretty forgiving. That's pretty good in a 5000 ft3 room and is way beyond what a series of big velodynes can do for example. When you use the tactiles, the sub does not "need" to be turned up as high to sound/feel as good as with no tactile.
 

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The Kenwood KSC-WA62RC is Awsome and easy to install

First, I'd like to say thanks to everone on this thread for giving me the idea in the first place. I purchased the Kenwood powered sub from Crutchfield for $189 with no tax or shipping. I also picked up two cables from midwestelectronics.com: AUX2 input cable for Ipod/XM radio (#7607001504 - $17.95) and PREAMP out cable (#F00E500014 - $14.95). I already had a 15 foot RCA cable to run to the subwoofer. Using the radio removal tool that came with the car, I slid out the radio and plugged the two cables in and routed them to the right-side pocket using the channel behind the dash. I then ran the RCA and blue "amp switch" wire against the firewall and under the passenger-side carpet to the back shelf. By removing the bottleholder/aux power housing on the rear firewall, it was simple to find a power source and a good ground. As for mounting the sub, I'm using "earthquake-rated" velcro and also tied the sub to the cargo net with wire ties just to be safe. In all, the whole installation took me about three hours and it's pretty easy to remove.

For me, the sound is awesome, it fills in just the right amount of bottom end, but doesn't shake the car next to me. I have a strong interest in Techno music and the subwoofer does great with all my MP3 files. I find I do need to adjust the gain when switching from disks to the radio since the tuner seems to play louder. As far as the installation, I drove rather aggressively today and the thing didn't budge. My passenger commented on how nice the sound was, even at freeway speeds.

I would highly reccomend this setup for anyone out there looking for an inexpensive upgrade to the existing system. It won't blow the doors off but it makes the stock stereo something I can finaly live with.

I've enclosed a few install pictures, including one with the seat all the way back. No cuttling or drilling was required for the install, everything can be removed and returned to "stock" condition.

Hope this helps some of you out there.

ps- the car is an Ardent Red Touring with the Acapulco MP54 head unit.
 

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1FASTMX5 said:
**Correction it's 60watts RMS 70 Peak per channel. I believe the most of any current HU.**

Panasonic CQ-C9800U High Power Car CD Player Digital internal amp, 60 watts RMS x 4
I was researching the Panasonic CQ-C9800U head unit compared to the Alpine 9833, and discovered that there is an error at Crutchfield's website where it lists the RMS power at 60W. It is actually 31W at 1% THD (as per the CEA-2006 standard). The Alpine 9833 unit, which is listed at 26W RMS, is quoted as per this standard (so you can make apples-to-apples comparions). Otherwise, manufacturers quote all sorts of power numbers at high distortions. (Such as peak power - is it 10%THD, 50% THD, completely clipped [ouch!], etc. - makes a big difference.)

The Crutchfield Advisor website did a review of the Panasonic CQ-C9800U, and listed it as 60W RMS per channel, but the editor later put in a correction saying that it is actually 31W RMS at 1% THD. You can see this at the bottom of the page referenced here:
9800U review - look at bottom of page

The later models, the 9801U and the 9901U, which have exactly the same amplifier in them as the 9800U, both are listed as 31W RMS on Crutchfield's site. Crutchfield has simply not corrected the 9800U listing. I sent them an email tonight calling out the error.

So, I bring this up because if you are trading off features of the Alpine 9833 versus the Panasonic 9800 (or 9801 or 9901), then I don't think I would worry too much about the 5W RMS difference. If it really was 34W difference, that would be a real issue, but, it isn't. However, because the Panasonic unit does use a Class T amplifier, it should consume less total power from the electrical system than the Alpine unit (class T amps are more power efficient), which might be a consideration to you.

By-the-way, I did look up Tripath's data sheets on this (they make the class T amplifier used by Panasonic), and they list better power at 1% THD than Crutchfield does. However, Tripath tested at 24V, whereas RMS is quoted with power supplied at 14.4V to the head unit (the electrical system voltage when the engine is running, which is then lowered a bit further inside the head unit due to voltage losses). The lower voltage degrades performance (common trait of most amplifiers).
 

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I should add that if I was to add a separate high power amplifier, I might go with a class T amp simply because they produce much less waste heat. Hence, there would be fewer problems keeping it cool, particularly in air-starved mounting locations (such as in a trunk, in a door panel, etc.).
 

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ChrisH said:
I was researching the Panasonic CQ-C9800U head unit compared to the Alpine 9833, and discovered that there is an error at Crutchfield's website where it lists the RMS power at 60W. It is actually 31W at 1% THD (as per the CEA-2006 standard). The Alpine 9833 unit, which is listed at 26W RMS, is quoted as per this standard (so you can make apples-to-apples comparions). Otherwise, manufacturers quote all sorts of power numbers at high distortions. (Such as peak power - is it 10%THD, 50% THD, completely clipped [ouch!], etc. - makes a big difference.)

The Crutchfield Advisor website did a review of the Panasonic CQ-C9800U, and listed it as 60W RMS per channel, but the editor later put in a correction saying that it is actually 31W RMS at 1% THD. You can see this at the bottom of the page referenced here:
9800U review - look at bottom of page

The later models, the 9801U and the 9901U, which have exactly the same amplifier in them as the 9800U, both are listed as 31W RMS on Crutchfield's site. Crutchfield has simply not corrected the 9800U listing. I sent them an email tonight calling out the error.

So, I bring this up because if you are trading off features of the Alpine 9833 versus the Panasonic 9800 (or 9801 or 9901), then I don't think I would worry too much about the 5W RMS difference. If it really was 34W difference, that would be a real issue, but, it isn't. However, because the Panasonic unit does use a Class T amplifier, it should consume less total power from the electrical system than the Alpine unit (class T amps are more power efficient), which might be a consideration to you.

By-the-way, I did look up Tripath's data sheets on this (they make the class T amplifier used by Panasonic), and they list better power at 1% THD than Crutchfield does. However, Tripath tested at 24V, whereas RMS is quoted with power supplied at 14.4V to the head unit (the electrical system voltage when the engine is running, which is then lowered a bit further inside the head unit due to voltage losses). The lower voltage degrades performance (common trait of most amplifiers).
Thank you, I feel beter about my alpine 9835 at 26RMS. At the time I bought it, Iwas told that had the most powerfull & cleanest amp of the head Units out there. So now how does one determine the how clean an amplifier is?
 

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Obviously, you open it up and look at it. :)

Though, I think when "they" say clean, "they" mean low distortion levels at high output over the entire frequency range. So, basically, you look at the sine wave going in to the amplifier, and check to see that it looks the same when it comes out only with greater magnitude.
 

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keep in mind that the measurement "stick" for power output is still subject to a great amount of varience.... the reason that they are able to do this is because there are still no standards as to how a manufacturer goes about taking a measurement for power output. The most common way to skew the results is to pick and choose the frequencies at which you take your measurement; i.e. amplifiers should be measured at a particular %thd and then the average power over 20hz-20000hz. this is how high end home reference amps are all measured in the stereophile mags. a manufacturer that wants to get a better number can simply choose to measure at say 1000 hz, one of the easiest frequencies to produce power at and will produce 2-4x the power as opposed to over the entire range of frequencies. Another big trick is to use resistive loads to measure output power; this means using a set of big ceramic resistors instead of speakers as an output, which is MUCH easier to keep an amplifier running in a stable mode.

The point is that there is no real standard for measuring output power so the best bet is simply to A/B the units before you buy them...
 

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ChrisH said:
However, Tripath tested at 24V, whereas RMS is quoted with power supplied at 14.4V to the head unit (the electrical system voltage when the engine is running, which is then lowered a bit further inside the head unit due to voltage losses). The lower voltage degrades performance (common trait of most amplifiers).

All of the newer high power headunits incorporate switching power supplies that produce an internal "rail" voltage that drives the amplifier (the little 1"x 2" metal box attached to the main headunit by a cable) . this is because the laws of physics dictate that the greatest rms output power available is:

Pmaximum_rms = ( V / ( 2 x 2 ) )2 / R

which at 13.8 volts works out to be around 6 watts per channel (at 4 ohms). so a non switched mode unit can put out a total of 6 watts rms x 4 or 24 watts rms.

the new switched mode power supplied units like the panasonic and others internally boost the power to the chip much higher, usually to somewhere in the area of 24-48 volts and this is where the 24 volt test value for the tripath unit comes from. the panasonic unit is definately running at least 24 volts internally.



Finally, one easy way to determine the maximum possible RMS output power of any headunit is simply to look at the fuse wattage rating for that unit. the total possible RMS power available by a given unit is:

Prms=V *Afuse*(eff%/100)

where eff is the efficiency percentage of the particular amplifier type (class A= 20%, class AB=50%, class D/T=80%)

so for the panasonic in the elise for example: the voltage at the radio harness with the engine running is 13.8v, the fuse on the back of the 9800 series is 15 amps, and the tripath circuit is ~80% efficient.

Prms= 13.8 * 15 * .80 = 165.6 Watts or ~40 watts rms per channel.

of course in practice, the actual power will be a little bit less as some power is used to run the cd transport and control circuitry and the switching power supply is typically around 80-90% efficient as well but even given that, say 1 amp is used for the cd and HU lighting and the power supply is 80% efficient...

Prms = (13.8 * 14 * .80) *.80 = 123.6 watts rms or ~31 watts rms per channel

which is what is listed as rms power. compare this to a class AB amplified HU even with a 20 amp fuse....

Prms = (13.8 * 19 * .50) *.80 = 104 watts rms or 25 watts per channel.



The real limiting factor for a class T HU is going to be the fact that vehicles have 20 amp feeds for their head units and that will limit the output power to around a maximum of around 50 watts rms per channel. any further increases are going to require running better supply lines to a power point or the battery. Alas, this is probably not even needed; for mid/high frequency reproduction, even 31 watts rms per channel is more than sufficient, especially in the elise. once again, where it is sorely lacking is the bass/midbass response. running the 4 speaker full range causes them to be overdriven in an attempt to reproduce the low end of the frequency spectrum, which in turn creates additional distortion. The addition of an 8" sub with even 70 watts rms would make all the difference in the world. if a digital amp was used to drive it, it would only around 7.5 amps power! Adding crossovers to the mids/tweeters to run them highpass above 100 hz would actually allow them to run more efficiently and with much less excursion, allowing even more output given the same equipment.
 

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Surprise surprise. The Bazooka wouldn't fit; not even close. I'll look to the Kenwood or Clarion solutions next I suppose. sigh.
 

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Surferjer said:
Surprise surprise. The Bazooka wouldn't fit; not even close. I'll look to the Kenwood or Clarion solutions next I suppose. sigh.
Thanks for the update Surferjer! I didnt think it would and I'm sure glad I didnt order it. Too bad the other options are so low in power :(
 
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