Topic: School me on car audio stuff

[KDXSR5]

[blackdiamond]

I never said the input makes a difference. go ahead and push 1/2 ohm through a 4ohm stable amp at 500Watts. just do it. I am done contributing to the thread now that the "smart" people have joined in.

Easy trigger, I think we have some wires crossed...

We may be talking about different things here. 

Give me a few minutes and I'll post some additional info to see if I understand what KDXSR5 is planning to do.

[86bobbedtoy]

remember amps are rated to certain ohms
??x2 @ 2 ohms usually means less that that at 4 ohms.

[blackdiamond]

Ok, let me try to "paint" an overall picture of what we're trying to accomplish along with the areas that I have questions.  Contrary to what some might think I don't know everything about car audio, but I do understand more than a lot of people about what the ratings really mean in practice.

KDXSR5 has a head unit that has the following outputs:

2 EA front channel speaker wires (HI Level)
2 EA rear channel speaker wires (HI Level)
1 EA RCA L/R outputs (LOW Level) that is a rear channel signal

Note: My amp only has LOW Level inputs (RCA) so I'm not 100% sure how HI Level inputs differ.

KDXSR5 is talking about using a 4 channel amp to power the four main speakers, correct?

If so, I would expect that each of the channels would hook, via HI Level input, directly to the amp and would then each run from the amp to the individual speakers.  In this configuration, the ohm load of each channel would simply be what the speaker is rated for.  This would mean that there would be two front channel speakers and two rear channel speakers.  This configuration would be the only way to maintain individual left and right channel signals.

IF KDXSR5 were to hook multiple speakers to a single amp output (i.e. two sets of speakers per output) then the ohm load would change depending on if the speakers were hooked in parallel or series.  This is commonly a factor when hooking multiple subwoofers to a single channel amp.

The LOW Level output on the head unit could be used to hook to a second amp that was dedicated to the subwoofer and it would be running the rear channel signal, but I don't think he is planning to use a subwoofer at this point, correct?

The bottom line is that I believe that we're confusing him with the parallel vs. series connections of speakers because he is planning to run four individual channels, right?

I never said the input makes a difference. go ahead and push 1/2 ohm through a 4ohm stable amp at 500Watts. just do it. I am done contributing to the thread now that the "smart" people have joined in.

I'm positive that we're talking about different configurations based on your 1/2 ohm load calculation.

If my math is correct:

In parallel, 2 ohm + 2 ohm = 4 ohm & 4 ohm + 4 ohm = 8 ohm

In serires, 2 ohm + 2 ohm = 1 ohm & 4 ohm + 4 ohm = 2 ohm

As long as each speaker is running on an individual channel the ohm loads are not combined, correct?  He should only have to make sure that any individual speaker has an ohm load that matches what the amp is rated for.

My Kenwood amp has the following rating
920 watts peak
&
150 watts RMS x 2 channels with 4 ohm speakers
or
230 watts RMS x 2 channels with 2 ohm speakers (more watts equals more heat which is why a lower ohm load can result in the amp overheating)
or
460 watts RMS x 1 channel with a 4 ohm speaker (it appears that the amp could overheat if a 2 ohm speaker was used in a mono configuration as the watts could increase beyond the cooling capacity of the unit)

Duffil - I'm not trying to be a jerk at all, I just think were talking about different things and not communicating clearly.  I resource my electrical engineering buddy before I hook anything up because he's my resident expert.  He has taught me what the ratings really mean and how they translate into actual practice.  I'm positive that you have more working knowledge than I do when it comes to actually hooking up the system and you obviously have significantly more knowledge than the average "Joe" so please keep providing input.

I can't figure out where you're getting a potential 1/2 ohm load? 

[fordh8r]

If my math is correct:

In parallel, 2 ohm + 2 ohm = 4 ohm & 4 ohm + 4 ohm = 8 ohm

In serires, 2 ohm + 2 ohm = 1 ohm & 4 ohm + 4 ohm = 2 ohm

The math is correct, circuit type was incorrect though. 

One rule of thumb when looking at ratings of any audio equipment (I.E. amps, speakers, etc...) to somewhat gauge the quality of the equipment is this.

If you see the words/terms "Music power", "peak power" or "max power" preceded by it's wattage rating it can be safely assumed this is not a high quality unit. The difference between these terms and RMS usually is about twice that of the RMS rating. This rating is so false because you can't actually run the components in this wattage rating with it being highly distorted or at the risk of burning up.

If you see the rating lited as "RMS" then the rating is usually more solid and can lead you to a better quality unit simply because this rating is something that can be run at this power for continued periods without failure. In regards to amps as far as speaker loads go (Output ohm rating) along with the "RMS" rating the lower the "ohms" rating usually the better the unit. But make no mistake, the price will easily reflect this as well. How this matters basically is the lower the ohms of the "speaker load" the closer it is to being a "shorted circuit" which is why an amp will get hot and with better circuitry it can withstand more heat for longer periods before sucumbing to damage. Again, make no mistake a high quality amplifier still needs cooling and they will get hotter if they are loaded to their max.

Which brings up another point....your charging system. While you're adding all this cool stuff don't be fooled into thinking you can run it for hours while not running the engine or at real low speeds cause this stuff takes big power to run if you run big stuff. I've had stereo systems in excess of 1KW and they are a lot of fun after you work out all the bugs.

BTW, get an electronic crossover and make it all worth it! So much easier to hook up and far more adjustable and enjoyable.  HAve fun putting it all in. 

[brockbuilt85]

im glad i know enough about car stereo to make my stuff sound goo on my own, cause you guys would all be confussing the out of me

[fordh8r]

im glad i know enough about car stereo to make my stuff sound goo on my own, cause you guys would all be confussing the out of me

Stick around and become one of the unconfused among the confusion.  That compares to standing in a fart cloud and not being bothered by it. 

[blackdiamond]

Considering the constraints that KDXSR5 is dealing with, I would probably just run the front speakers directly from the head unit (I don't think an aux amp would greatly improve the overall sound quality).  Unless a subwoofer is in the plan you could run the LOW Level RCA inputs to an aux 2 channel amp and simply use it to power the larger rear channel speakers.  I believe this would make the installation fairly simple, minimize cost and still yield an improved sound.

The math is correct, circuit type was incorrect though. 

What do you mean by circuit type?

[fordh8r]

Considering the constraints that KDXSR5 is dealing with, I would probably just run the front speakers directly from the head unit (I don't think an aux amp would greatly improve the overall sound quality).  Unless a subwoofer is in the plan you could run the LOW Level RCA inputs to an aux 2 channel amp and simply use it to power the larger rear channel speakers.  I believe this would make the installation fairly simple, minimize cost and still yield an improved sound.

This could work and be about as low buck as it could get.... but how "low buck" and how "high quality" you're looking for will narrow it down to what you really want or end up with.   


What do you mean by circuit type?

 Sorry, I probably should have said that your labeling of the circuit types was reversed as far as series and parallel.   

[blackdiamond]

You're correct that I had them backwards.  I actually realized that I was thinking backwards a few minutes ago when I called my buddy to confirm a couple of things so I wouldn't lead KDXSR5 in the wrong direction.

[jrock]

Sorry to hijack, I have a quick question:
MTX TXC6.0
What is this and how well does it work? It is the last one at the bottom of the page.
http://images.google.com/imgres?imgurl=http://www.extremebassaudio.com/sitebuildercontent/sitebuilderpictures/TXC6.gif&imgrefurl=http://www.extremebassaudio.com/catalog/c27_p1.html&usg=__RvmDjEDr4tbzw8bjCmieleJOwlQ=&h=492&w=738&sz=124&hl=en&start=1&tbnid=15tBp86PafswSM:&tbnh=94&tbnw=141&prev=/images%3Fq%3Dmtx%2Btxc%2B6.0%26gbv%3D2%26hl%3Den%26safe%3Doff

http://www.techronics.com/index.cfm?Product_ID=3107&fuseaction=product.display

[THK Matt]

I say run really good 6.5" speakers in the doors, 6.5" or 6x9's in the rear and run it directly off the head unit... take most of the lows/bass out of them... turn your highs all the way up, treble a notch or two down from that and fade the sound to about 60% rear and then run a single 10" sub through a mild wattage amp.

you will VERY surprised on how well it will sound.. .and you wont distort anything!

this can be done fairly cheap.

I have a Kenwood Deck, Sony xPlod 6.5's front and rear, JBL 400w 2ch amp pushing a 750w 10" Lightning Audio and a 700w 12" Kenwood.

just my $.02

[fordh8r]

Sorry to hijack, I have a quick question:
MTX TXC6.0
What is this and how well does it work? It is the last one at the bottom of the page.
http://images.google.com/imgres?imgurl=http://www.extremebassaudio.com/sitebuildercontent/sitebuilderpictures/TXC6.gif&imgrefurl=http://www.extremebassaudio.com/catalog/c27_p1.html&usg=__RvmDjEDr4tbzw8bjCmieleJOwlQ=&h=492&w=738&sz=124&hl=en&start=1&tbnid=15tBp86PafswSM:&tbnh=94&tbnw=141&prev=/images%3Fq%3Dmtx%2Btxc%2B6.0%26gbv%3D2%26hl%3Den%26safe%3Doff

Best I can tell, it's a 6 1/2" woofer with a crossover. They say it's a two way, but I don't see a tweeter mounted to the speaker which would normally be called a coaxial speaker. So I wonder if it's a two way crossover to allow the addition of a tweeter to be mounted seperately of the woofer.  If that makes any sense.  Have you looked up the specs on the MTX site? Maybe I'll look it up and see if it tells more than that listing.   

[jrock]

I know nothing about any of this. Someone wants to trade me this for some of my tires. I would like to know if I could use it for anything or is it just bass?

[blackdiamond]

Sorry to hijack, I have a quick question:
MTX TXC6.0
What is this and how well does it work? It is the last one at the bottom of the page.
http://images.google.com/imgres?imgurl=http://www.extremebassaudio.com/sitebuildercontent/sitebuilderpictures/TXC6.gif&imgrefurl=http://www.extremebassaudio.com/catalog/c27_p1.html&usg=__RvmDjEDr4tbzw8bjCmieleJOwlQ=&h=492&w=738&sz=124&hl=en&start=1&tbnid=15tBp86PafswSM:&tbnh=94&tbnw=141&prev=/images%3Fq%3Dmtx%2Btxc%2B6.0%26gbv%3D2%26hl%3Den%26safe%3Doff

http://www.caraudio4less.co.uk/mtx-65-midbass-driver-txc60-p-1382.html?zenid=c204e021e56b1f2f3b4d6a733b49055e

It appears to be a mid-bass component speaker.  This means that it is designed to only handle a limited range of sound frequencies and must be used in combination with other component speakers to get a full range of sound.  It is just part of the total package that would be required.  I have never messed with component speakers so I don't know what to tell you other than the basics.

[fordh8r]

It appears to be a mid-bass component speaker. 

it is.


The pic in the link you posted blackdiamond shows the seperate tweeter that is included in the package as I somewhat suspected. 

 Those look like pretty decent speakers. They're a bit pricey for what they are so I might shop around to see how much the price may vary from one place to another. Don't exclude checking with local audio dealers since you never know what sorta deals they may be willing to make.

 I'm usually partial to a brick and mortar establishment myself since you can see the items in hand and get a better idea of what might be involved when it comes to fit and installation. Maybe that's just me. 

[jrock]

Thanks for the info. This sounds like something I will never need. To bad for that other guy. Thanks.

Back to the topic.

[Hawk Thor]

I canŽt believe nobody has suggested adding sound insulation.

When I moved my Alpine Type-S 6.5" co-axials to my current truck I also put some tarmat in the front doors. I put a double layer on the outerskin to prevent vibrations and block out road noise. I put a single layer on the inner skin to prevent vibrations and to make the door tighter.

By closing all the holes in the inner skin your woofer will provide much sharper and detailed midbass. If the backside of the speaker is not well sealed from the front side you will get less than desired performance from your speaker. If the soundwaves from the back react the front you will get cancelling, the soundwaves will cancel each other out to some degree.

I noticed that my midbass was much sharper then in my old truck and there was not as much rattle when I turned it up. I also greased the rods for the locking mechanism so they stopped rattling. I also have extra insulation on the bottom/floor of the cab, this is a mat that is laid under hardwood floors, its a rubbery poly something. It works great and is easy to take out and put in.

I plan on putting tarmat in the rear doors as well, back of the cab, top and floor. This should make it much nicer to daily drive then the all vinyl interior I have now.

[blackdiamond]

I canŽt believe nobody has suggested adding sound insulation.

When I moved my Alpine Type-S 6.5" co-axials to my current truck I also put some tarmat in the front doors. I put a double layer on the outerskin to prevent vibrations and block out road noise. I put a single layer on the inner skin to prevent vibrations and to make the door tighter.

By closing all the holes in the inner skin your woofer will provide much sharper and detailed midbass. If the backside of the speaker is not well sealed from the front side you will get less than desired performance from your speaker. If the soundwaves from the back react the front you will get cancelling, the soundwaves will cancel each other out to some degree.

I noticed that my midbass was much sharper then in my old truck and there was not as much rattle when I turned it up. I also greased the rods for the locking mechanism so they stopped rattling. I also have extra insulation on the bottom/floor of the cab, this is a mat that is laid under hardwood floors, its a rubbery poly something. It works great and is easy to take out and put in.

I plan on putting tarmat in the rear doors as well, back of the cab, top and floor. This should make it much nicer to daily drive then the all vinyl interior I have now.

You are correct, but I think this is beyond what he's wanting at this point in the stereo exploration.  Since he was asking about the basics I figured we should work on the basics first.  I would love to have someone put dynomat in my 4Runner and Mazda.

[-Matt-]

since dynomat is like 10$ a square foot...you can get the same stuff but its designed for roof flashing, you can pick it up at most contractor building supply store. you can get a big ass roll that will do every inch of your truck x2 for like 40$

[THK Matt]

since dynomat is like 10$ a square foot...you can get the same stuff but its designed for roof flashing, you can pick it up at most contractor building supply store. you can get a big ass roll that will do every inch of your truck x2 for like 40$

NICE!

is it actually called flashing?
i thought flashing was the right angled metal strip that went around objects and on the eve's

[Hawk Thor]

since dynomat is like 10$ a square foot...you can get the same stuff but its designed for roof flashing, you can pick it up at most contractor building supply store. you can get a big ass roll that will do every inch of your truck x2 for like 40$

What I used is similar to those. It was some leftovers from a big rig shop. They use it on flatpanels to stop them from flexing and vibrating. It has aluminum backing and what looks like tar to makeŽem stick. Smells bad but the smell fades fast.

[-Matt-]

What I used is similar to those. It was some leftovers from a big rig shop. They use it on flatpanels to stop them from flexing and vibrating. It has aluminum backing and what looks like tar to makeŽem stick. Smells bad but the smell fades fast.

ya thats what im talking about the stuff iv used didn't even smell bad to begin with, but it works just like dynomat, i put a whole crap load of that in my buddies 86 runner when we put his system in and it made a huge difference. and its not called that, i actually don't know what its called.. but they use it with roof flashing applications.

[THK Matt]

This stuff?

http://www.homedepot.com/webapp/wcs/stores/servlet/ProductDisplay?storeId=10051&langId=-1&catalogId=10053&productId=100386646&N=10000003+90094+501163

[Hawk Thor]

Look for Fat Mat. Its really good but it only costs like a quarter of what butyl based sound deadeners cost.

I donŽt know what brand I used, it was sticky and had thick aluminum foil. There might be some smell on hot days but drive with windows down for half a minute and its gone. This also works as heat insulation, keeps the heat out in the summer and the heat in during the winter.

[-Matt-]

This stuff?

http://www.homedepot.com/webapp/wcs/stores/servlet/ProductDisplay?storeId=10051&langId=-1&catalogId=10053&productId=100386646&N=10000003+90094+501163

ya ist similar to that stuff, but what i use is aluminum with sticky tar on the back side instead of vinyl. i also believe its thicker couse that stuff looks pretty thin. but ya basically its the same stuff.

 

[THK Matt]

this crap is cheap.. I need to buy this and pull my interior completely out and insulate it... maybe a summer project.. or when I have the time to do it.

[Plekto]

Beat me to it on the doors.  They will bounce and vibrate like a drum head if you don't put something to dampen them a bit inside them.  Of course, the best option is to make a speaker enclosure inside the door itself.

My suggestion:
Your current head unit will work fine for any four basic speakers up to hearing damage levels.  I would toss the small fronts and go with a pair of 6-7 inch 3 way Kenwoods.  these seem to be the biggest bang for the buck.  they make two main lines - get the more expensive set.  Last time I checked, the difference was only like $20 between the two.  Round speakers sound cleaner and more accurate than oval ones, and 6.5 inch is plenty large.

Get a set of 1 inch riser rings.   Then make a plastic or metal box for the back side of the door/inside. Rears need a large cabinet of some kind.

As for the sub - ignore it.(see below)

http://www.kenwoodusa.com/Car_Entertainment/Speakers/7''_Speakers/KFC-C1739ie
4 of these would make a sub not required.  30hz is as low as most subs go outside of movie sound effects and the like.(It's basically one note, give or take a bit, above the last note on a piano)

But, honestly, even 4x 6.5s of high quality will nearly make you deaf.  The trick is the DIY cabinets for each speaker - they need to be as close to air tight as possible to keep the things from sounding tinny.  In fact, with most speakers, the cabinet usually makes a larger impact than the actual drivers. 

4.0 always sounds better than 4.1, but it requires large main speakers and a good amp.  Subs have always been a method to cheat a bit. In home theater, especially, a sub is good, because people don't have speakers the size of a small fridge.  But in a car, there's tons of space in the doors and rear behind the seats to make the speaker boxes.  A big cabinet like what was posted would give you enough room to get pretty good low frequencies.  A 7 inch woofer will go as low as you need for any rock or jazz or hip-hop or...  Larger speakers generally waste space and only offer more air movement(which is annoying IMO in a small enclosed space like a car).  You want good bass and not one tone "thump thump thump".

This is why it's better musically to have a small stack of 8 inchers if you play bass as opposed to a chuffy 12-15 inch single driver - the bottom note on a 4 string bass isn't even 40hz!(41.204 hz).  A 5 string is 30.868hz, which is as low bass notes go with rock and pop and so on. 

If you get 6.5s, which I found fine in my last car as well, get these:
http://www.kenwoodusa.com/Car_Entertainment/Speakers/6.5''_Oversized_n_6.5''_Speakers/KFC-1682ie
35hz vs 30hz isn't a huge compromise.  Possibly use these for the front if space is tight.

..and *NOT* these (cheaper ones you normally find):
http://www.kenwoodusa.com/Car_Entertainment/Speakers/6.5''_Oversized_n_6.5''_Speakers/KFC-1661S
Big difference in the clarity(not good) and just not worth saving $15-20.

I mention these because they would still sound good and don't require totally custom fitting and cutting in many cases(riser rings, covers, cabinets, etc - all normally come with 5-6.5s in mind)

But those 7s are beautiful... 4 of them would only set you back $140, tops. 

[blackdiamond]

4.0 always sounds better than 4.1, but it requires large main speakers and a good amp.  Subs have always been a method to cheat a bit. In home theater, especially, a sub is good, because people don't have speakers the size of a small fridge.  

This is why it's better musically to have a small stack of 8 inchers if you play bass as opposed to a chuffy 12-15 inch single driver - the bottom note on a 4 string bass isn't even 40hz!(41.204 hz).  A 5 string is 30.868hz, which is as low bass notes go with rock and pop and so on. 

35hz vs 30hz isn't a huge compromise. 

Why do you say that 4.0 sounds better than 4.1?  Are you talking car audio or home audio?

I completely agree that a subwoofer's primary purpose is for movies in home audio surround sound setups, but they can also perform well for other types of music if balanced with the rest of the system.

When it comes to rock & roll music the subwoofer isn't needed to reproduce a quality sound, but a subwoofer can make an incredible difference with Mannheim Streamroller music.  I say "can" because the performance of the subwoofer is strongly tied to the environment that it is in.  Generally, the home audio environment is conducive to much lower frequencies compared to car audio (35 vs. about 50).

If you have ever heard the Mannheim Streamroller Christmas Extraodinaire CD, the song Hallelujah has amazing bass if the room and subwoofer combination can reproduce it.  I used to live in a rental house where the resonant frequency of the room was about 35hz and that song sounded like a herd of elephants would run from right to left across the room.  My house, with the same speakers, simply won't reproduce the same sound (it's really sad) and my 4Runner system doesn't even come close.  The song is on another one of their CDs and the bass was removed from that CD for some strange reason.  On most systems there isn't any audible difference.

While a string bass can be reproduced without a subwoofer, I would think that something like a tuba would benefit from the added air movement to reproduce a more realistic presence?

I'd like to hear your sounds systems, I suspect they are high quality and sound great! 

I have a set of Infinity IL-50s for my home audio (amazing bass and vocals) and I'm eagerly waiting for my Bose On-Ear headphones to arrive for work.  The IL-50s come with a RABOS bass optimization system that lets me tune the bass response to the room.  I can filter out the bass level at the resonant frequency of the room which allows me to bring the overall bass volume up without losing musical balance.

[Plekto]

You hit upon it - the wavelength of frequencies below 40-50hz is far beyond the size of the cab, so it's largely going to just sound one note-ish below that anyways.   It'll eventually rattle the entire cab apart as well - because that sound pressure has no place to go in such a small space and then starts to vibrate everything that's at or near its resonant frequency.  In a 4Runner, way in the rear, it would probably make a difference, because there's just enough space inside the shell to get some bass extension that's not muddy.

At home, with a large enough room, it's great, of course.  But cars are a small and usually pretty tightly sealed environment, compared to a typical living room.  Rattle the windows, feel the bass in your chest sort of thing - but not really doing you or your hearing any good.   Those 7 inchers are actually kind of overkill.  At under $50 a speaker, it's a killer deal as well.

No - they really do sound quite nice.  Spend money on fancy Alpines or Infinity or whatever if you want - the Kenwoods are 95% as good for a fraction of the price.  Better than JBL's car audio and Bose, btw. (note - NOT true for home audio - heh)

Oh - movie theater subs are set at roughly 35-40hz in order to not cause long term damage to the buildings.  They make up for it in volume and air moved, of course.  But it's hardly musical.