So About That Vehicle Of Yours...

Postby gyre » Wed Jul 29, 2009 3:46 pm

ChillyFire wrote:yea boijoy, im not gona take the 395 all the way up to the 80, im going 395 to 95, to the 447, its just a huge straight line from san diego to gerlach, easy as pie, but i do know i will need some cooldown spots still.

im not sure where the vdub camp is? anybody? some insight? i'd love to park there, cause my bus is soooo crazy right now, yesterday i just had a new boston acustics sound system put in, and i just got a 1200w kenwood sub for the back, all super cheap too! and my flower child mom is comin along, haha, so we'll only be bumping great music for all people

I wasn't aware kenwood made a 1200 watt amp?
1200 watts is more horsepower than a vw can produce.

KEP has some ways to fix reliability issues and some good clutches too.
http://www.kennedyeng.com/index.htm
http://www.kennedyeng.com/sub_van.htm
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Postby pizzamancer » Wed Jul 29, 2009 4:08 pm

The Honda Super Cub, the most fuel efficient vehicle on the planet.

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BRC sticker courtesy of sticker camp Thanks! )'(
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Postby ChillyFire » Wed Jul 29, 2009 4:10 pm

gyre wrote:I wasn't aware kenwood made a 1200 watt amp?
1200 watts is more horsepower than a vw can produce.

KEP has some ways to fix reliability issues and some good clutches too.
http://www.kennedyeng.com/index.htm
http://www.kennedyeng.com/sub_van.htm


ahh its not a 1200 watt amp, its a 1200 watt subwoofer, 1200 watt peak, 4-800 watt rms. ill be running it through a kenwood x600f amp
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Postby gyre » Wed Jul 29, 2009 4:50 pm

Just for general information-

There is really not any such thing as peak or max power.
It is meaningless.

RMS ratings without distortion measurements also mean nothing.
A useful power level is one with a distortion level of 0.0X % at X watts rms.

All amps produce more power than will run clean.

Speaker ratings need to include a time period with wattage levels to be useful.
A reliable company may provide a constant rating (constant meaning constant, as in 24 hours a day) and a ten second power rating.

Sensitivity is, of course, the most important thing to know about a driver.
This is typically measured at 1 watt rms at ten feet in decibels, or one metre.
This determines how loud a speaker can be.
Depending on intended use, a company may rate a driver higher or lower, based on the content expected to be used.

Besides peak power, there is also just general outright lying about equipment.

Don't forget that for music content, you need ten times the headroom of the average rms level.
There may be tolerated exceptions for direct electronic instruments.
This means that to play clean at ten watts you need a 100 watt reserve.

The X600F is rated at .05% at 400 watts into 4 ohms.
I don't think it will produce more than this clean when bridged or into lower impedance.
So that amp will do 40 watts average content with clean sound.
With an efficient speaker system, this is quite adequate though.
Remember that Eric Clapton played most of his sets with Cream using less power.

An efficient bass driver can produce 100 decibels at one watt.
High frequency horns can do far more than that.


Here are sample specs from a decent driver.

Specifications
Frequency Response (-3dB) 30 - 800 Hz
Sensitivity 1W/1m 98 dB
Max. SPL / 1m (calc) 125.8 dB
System Power Handling (continuous/program/peak) 600/1200/2400 Watts
Nominal Impedance (Passive) 8 Ohms
Chassis Size 18 inches
Speaker Type Components
Weight Net 10.6 kg ( 23.37 lbs )
Note that peak and program are probably specifically defined in their paperwork somewhere.
Without that, they are useful only for comparison to their own products.
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Postby ChillyFire » Thu Jul 30, 2009 3:09 am

ahh, thank you for all that information, im really good with alot of tech stuff, reaaaly good with programs and computers, but im relatively new to car audio, lol.
i decided to not go with the x600f, but i was looking into a kicker zx750.1, seems to be a better buy, for a lower price too.
i just got a new receiver today, to power my front and rear speakers, and since you seem to have more expertise than i do, i would love your recommendation for an amp for that kenwood kfc-w3011 sub i have, dont need much, just something that will run it well and efficient, while giving me some great loud bumping bass. im certain that i can learn about amps and speakers really quickly, but im looking to have this beast up and running by this weekend, for a festival down here by me, and im not looking for top of the line by any means, just something that will work. i bought a kicker zx300.1 today, which was mislabeled on the frys electronics sticker, and i was given the wrong one by the sales associate, the sticker and the associate both told me that it was 300w constant at 4omhs, when the rating on the amp is only 150w at 4, but 300 at 2.
last time i ever follow what a stoned ass associate says unless i can actually check out the product. (especialy if im stoned myself, which im usualy not when i go shoping, lmao)
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Postby gyre » Thu Jul 30, 2009 4:33 am

Bear in mind that most companies are specing amps at 14.4 volts and you won't usually see that at the amp.
It also makes a 12 V rated amp seem less powerful than it really is.

All I can find on the kicker site is a rating at 1% THD, which is not that useful.
We are left to guess at useful power unless you can get more info calling them.
They rate the 750 at 375 watts into 4 ohms, which is the impedance I found on the kenwood speaker, though they carry a lot of 8 ohm stuff.
But that is at 1% distortion.
I think that makes the kenwood the more powerful amp.
The kicker is also a mono amp, which can make it cheaper to make, but that is all it can be used for.
The Kenwood is a bridgeable 4 channel amp, always easier to sell.
Since you don't quote prices, I can't compare there.
All I know about kicker is that crutchfield has had good experience with them.
The kenwood amp probably has far better signal to noise specs than the kicker, which matters a great deal to me.
It may not to you, but differences are audible.
I find contradictory specs listed on these products.

Many say kenwood amps are overpriced.
Most of my car equipment is kenwood, about half being excelon.
I have never used kenwood speakers though.
I have a kenwood amp 70-100 w/ch which is bolted in my race car and has survived track use with no issues.
Same with the cd changer, though vibration will destroy any loaded cds.
(It was not shock mounted as I would have done it.)
Kenwood strived to publish conservative amp specs long after others quit.
They would often rate hifi specs at 10 watts, higher distortion at 12 w, and the 1% level at 15 watts, giving people the range of misrepresentation involved in car decks.

I only use stereo speakers because all spatial imaging is lost with bass in mono.
This may not matter to you for sound reinforcement, but it does make a difference even for this application.

It is worth noting that most people buying losermobile car stereos seem to be interested only in the wattage the speaker can burn up, not the audio produced.
I ran across someone bragging about an FI BTL, which seems to be such an awful piece of crap that the company lists no sensitivity specs whatsoever.
They claim it will absorb 2000 watts though.
So most drivers are being made less efficient and rated at higher wattage.
Also an efficient driver that can handle more power usually becomes less efficient, mostly due to weight and stiffness.
A longer throw can also destroy efficiency.

It is better to get a very efficient driver and a smaller amp, if volume is the priority.
Also total consumption of power by the amp may vary a lot, if that matters to you.

The kenwood driver is rated at 90 db sensitivity which is mid-pack.
Since you have it, I would get the best amp you think you need and can afford and see how adequate it is, and add more efficient speakers if you are unhappy.
Once you have 70 watts or so, more power does not make as big a difference as you might think.

Also, many speakers power ratings are vastly overstated.
An efficient 15" driver often will not take more than 200 watts to produce it's maximum level.
Newer pa drivers are built for higher levels, but there is always something lost.

dB and Power (20dB = 100x)

When talking about power, 3dB represents a ratio of two to one or a doubling of power.

* Thus, a gain of 10dB would represent a ratio of ten to one for power - so 10 dB be 10 times the power
* A 40dB power gain would be 10,000 times the power.



A sample of some high power, and high efficiency drivers.
http://www.electrovoice.com/productfamilies/70.html


http://www.kenwoodusa.com/Car_Entertain ... /KFC-W3011
http://www.kenwoodusa.com/Car_Entertain ... iers/X600F
http://www.kicker.com/sites/default/fil ... %20web.pdf

http://trace.wisc.edu/docs/2004-About-dB/
http://en.wikipedia.org/wiki/Decibels
http://www.phys.unsw.edu.au/jw/dB.html
http://hyperphysics.phy-astr.gsu.edu/hb ... nd/db.html
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Postby gyre » Thu Jul 30, 2009 4:39 am

It is worth noting that some sub amps are of inferior quality, on the theory that it won't be audible in bass.
Look closely at any single channel amp.
Reviews of the 750 seem critical of the filters too.
It may depend on use though.

But some sub amps are not adequate for full range use at all.
Be sure about that if you plan on full range sound from the amp.
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Postby ChillyFire » Fri Jul 31, 2009 1:49 am

ahh thank you gyre for all the amazing information, i definately need to look it over a few times and save it for future reference.

i ended up keeping the amp i already purchaced, the kicker zx300.1, its not to bad for a starting amp, and when i desire for better sound quality ( and get some more $ in the pocket, lol) i now know what to look for.

the kenwood amp i was looking at, the x600, was being priced to me at $449, the kicker i purchased was $170. i bought the sub for $56 dollars, down from $100, new in box, gotta love the swap meet. i did buy a new pioneer reciever today, which isnt bad considering they listed the continuous power suplied to the speakers, not the misleading 52WATTSSS!!!! nonsense. glad i have at least something to play my music, even if it is only temporary, i would say it works for my first attempt at a sound system for my car =]
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Postby gyre » Fri Jul 31, 2009 3:21 am

Glad to help.
You should still have plenty of power.

For personal use, I definitely recommend stereo bass speakers, regardless of frequency.

I would suggest an infinite baffle cabinet for the speaker, if you have room.
Most car drivers will take a very small cabinet for this.
Kenwood ahould have specs.

If you are nuts enough, you could use an ultra long ported cabinet.
I have some speakers like this, becoming virtually rear horn loaded cabinets.
Mine are peaky but effective.
I think it acts as an infinite baffle until at such a low frequency that it doesn't affect linearity much.
A bulky approach though.


If you haven't run the numbers, remember that speakers work on a logarithmic scale.
This means that a 90 db driver needs 40 watts to do what a 96 db driver will do with 10 watts.
Or 400 watts to match 100 watts on a 96 db driver.
The speaker has to deal with all that heat too.
And in a car, you are talking about a substantial electrical load at full power.

Then add the ten times headroom needed and you can see the direction the numbers are taking.
This is why speaker sensitivity is so important.
And 90 db is not that bad.
Compare an 86 db driver or worse.

I hope it sounds good.
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Postby ChillyFire » Fri Jul 31, 2009 12:39 pm

ahh gyre you're awesome =]
now that i have some basic knowledge, or some quite good knowledge actualy, haha, i will know what to look for and can get my moneys worth when i go to purchase something.
im very greatful of that, and i would love for you to come to out bacon cookout, me and deb prothero and silverorange are all bringing awesome bacon to cookoff, and you're more than welcome to be there!(if you eat meat) im bringing some specialty bacon from this place called hodads, its soo amazing.
plus, im bringing a few fish tacos, not only fish tacos but south beach EPIC fish tacos, you've gota try one aswell.
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Postby gyre » Fri Jul 31, 2009 3:55 pm

Sounds great!
I only eat meat that has a face.
Or had.

Glad I could help.
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