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Old 10-30-2007, 07:34 PM - Thread Starter
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I recently installed a new Pioneer head unit into my Subaru WRX. I was looking at the ground wire that comes out of the harness, to ground the head unit, and I had it attached to a screw on the back of the head unit. I have not been happy with the level of audio coming out of the new speakers I installed (MB Quarts) in the front doors. I can crank the head unit to its maximum level, 62 on the volume scale, and it is loud, but it does not distort. I feel I should be able to turn it up to distortion levels at least, before it reaches its maximum volume level. Again, its loud, but feels like it should have a lot more. What could be other causes. Is grounding to the chassis of the head unit itself a bad idea? Could this be the cause of the low volume levels?
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Old 10-30-2007, 08:15 PM
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The volume is a result of power vs. speaker power handling & sensitivity. Im not sure what the sensitivity is of your MB Quarts, but if it's low, you won't get as much volume. To overcome this, you'd simply need more power from an outboard amplifier. I'm not advocating getting rid of the MBQ's though. Knowing part/model numbers of your HU and speakers would help.

The head unit grounding location has little to do with overall volume, but it could afffect system performance. I've really no idea how grounding the HU to itself would affect performance, but electricity is a strange animal. It is highly recommended to ground the heat unit to metal attached to the car's frame. A direct ground to the firewall, which is part of the frame, is best--no longer than 18" & preferably the shorter the better. Another piece of metal will work, but the ground wire from the harness to the head unit itself isn't an ideal ground. If you must extend the harness ground wire to make a good connection, be sure to solder the hell out of it and either tape the connection well or use heat shrink tubing to cover the connection. Metal to metal--make sure paint or any other insulator is not in the way--you can paint over the ground later when the connection is secure and you wish to prevent any rust. The HU ground is the most important ground in the entire system, so spending some time trying various locations is time well spent. Make sure the ground is absolutely secure & tight. The vast majority of ground problems I've seen are from owners who twist wires together...the other issues are from noisy, unshielded components (like cheap amps, EQ's, crossovers, etc.) and poor grounds.
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Old 10-30-2007, 08:25 PM - Thread Starter
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Thanks for the response. The speakers are MB Quart RUA 216. The head unit is a Pioneer Premier DEH-P490IB. I'm surprised the head unit can't push the MBs, at least to distortion. Also, I find that with this head unit like I have to crank it so far to get a noticeable sound level difference. Like when I have it cranked pretty good going down the road, and I get a call, with this head unit I have to turn the dial at least 4 full revolutions to get the audio down in a range where I can talk on the phone. This is annoying as heck. With my stock head unit, and all others I've ever dealt with, a simple half to three quarter turn or so would get it down to 0. Any ideas why this is happening? Do other owners with newer Pioneer head units have the same problem?
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Old 10-30-2007, 10:40 PM
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I've checked out your compoents. Wow! You've got a major mismatch! A HU that puts out 22w RMS to speakers with an 86db sensitivity...not good. Right away, these speakers are telling me that you need a high current amplifier. HU's are designed to drive high efficiency speakers; they cannot and are not designed to drive a significant load. There are two major types of energy sources in car audio: high power and high current. Generally speaking, high power produces the watts, but when placed under a heavy load (heavy load = low impedance), they fail because of the lack of current capability.

Think of it in terms of automobile performance. Power vs. Current. Power is like horsepower. Current is like torque. Horsepower will keep your race car going around the track, but torque will enable your 4x4 to pull through the mud pit your high horse car couldn't possibly handle (Mazda RX-8, Honda Civic hot rod, etc). In many cases, you will find torque/high current to be more useful than horsepower (Old school big blocks; 454, 510, etc). This is why there is a significant discrepancy between power ratings of HU's vs. amplifiers (and amps vs. other amps). Speakers present a load to amplifiers, and amps are (well, they should be) designed to handle the load they are given. Cheap foriegn amps look good on paper, but they can't drive **** on a stick. Any IC (integrated circuit) can put out power, but it takes real electronics to put out true torque (current).
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Old 10-30-2007, 10:47 PM
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You should most definitely choose a better ground. Right now your head unit is probably grounding through the antenna connection. If the factory harness does not have a ground wire, you need to crimp a ring terminal onto the ground wire and ground it to the chassis of the vehicle. You can do this by using a self-tapping screw and just screwing it into a solid piece of metal behind the dash, or find a bolt that is attached to metal. This will make a big difference. It should definitely distort the speakers at full volume, the reason its not currently doing it is because of a poor ground. Its grounding through the AM/FM antenna connection, so the ground path has to travel all the way to the fender where the antenna is mounted. You want the shortest possible path to a solid chassis ground.
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Old 10-30-2007, 10:50 PM
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i'm not sure what Lazonby was talking about with that metaphor, but you should get decent sound with that equipment. Its enough for the vast majority of people out there. Unless you really like to crank it you shouldn't need a separate amplifier. However if you're anything like me you LOVE to crank it up and should def look into adding an amp.
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Old 10-30-2007, 11:04 PM
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Quote:
Originally Posted by Lazonby View Post

The volume is a result of power vs. speaker power handling & sensitivity. Im not sure what the sensitivity is of your MB Quarts, but if it's low, you won't get as much volume. To overcome this, you'd simply need more power from an outboard amplifier. I'm not advocating getting rid of the MBQ's though. Knowing part/model numbers of your HU and speakers would help.

The head unit grounding location has little to do with overall volume

no offense but that is completely wrong. In his situation it has everything to do with it. He probably mounted the radio using a plastic dash kit, meaning the only connection to the chassis the radio has is through the antenna. If that is the case there will be a severe lack in performance.

In the vast majority of cars there is going to be a solid piece of metal behind the radio, such as a support bar or something like that. You can even ground to the metal that the factory radio was mounted to, as long as it is attached to ground.



+



+



+



+



+

solid piece of metal behind dash

=

easiest/best way to ground



if you arent sure what to ground to, PM me with a picture of the dash with the radio pulled out.
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Old 10-31-2007, 05:47 AM - Thread Starter
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Thanks for the replies. Before reading this a few minutes ago I did pull the head unit and find a new ground last night. There was a metal support bar behind the HU with a bolt in it that I used. The ground is now in an ideal location, but no difference in output from the HU. I can still crank it up the whole way to "62" and that's where it stops. Its loud, but not unbearable. I guess I need to start looking for an amp.
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Old 10-31-2007, 06:28 AM
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Originally Posted by gifty74 View Post

Thanks for the replies. Before reading this a few minutes ago I did pull the head unit and find a new ground last night. There was a metal support bar behind the HU with a bolt in it that I used. The ground is now in an ideal location, but no difference in output from the HU. I can still crank it up the whole way to "62" and that's where it stops. Its loud, but not unbearable. I guess I need to start looking for an amp.

so you're saying you have no audible distortion when you have the volume all the way up?
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Old 10-31-2007, 06:30 AM - Thread Starter
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Quote:
Originally Posted by oapy123 View Post

so you're saying you have no audible distortion when you have the volume all the way up?

Correct.
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Old 10-31-2007, 06:46 AM
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then something else is wrong...i have never once in my 4 years of professionally installing car audio come across a radio that does not produce audible distortion at full volume. How loud is it when you turn it up all the way? Comparable to what the factory stereo was or louder?
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Old 10-31-2007, 06:47 AM
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what model radio is it?
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Old 10-31-2007, 06:52 AM - Thread Starter
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Quote:
Originally Posted by oapy123 View Post

what model radio is it?

Its a Pioneer Premier DEH-P490IB. I agree, I've never had a head unit that would not distort at the higher volume levels, especially powering the speakers directly from the HU as I am. It sounds great at full volume. Its louder than my stock head unit was, but my stock system would distort up high.
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Old 10-31-2007, 07:37 AM - Thread Starter
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So I just talked to Pioneer tech support. He believes that the speakers are just plain underpowered. Looking at the MB Quart specs, the power range is 50-120W. The HU is only rated at 22W RMS, 50W max. So, at maximum HU output I'm only getting to the minimum rating of the speaker. Anyone have an amp they want to sell? Any good recommendations? I used to be into car audio years ago, and I always had great success with Rockford Fosgate. Are they still near the top for a Joe Smoe audio setup?
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Old 10-31-2007, 11:01 AM
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even if the speaker can handle more power, it should still be distorting at full volume. Thats really wierd. Maybe Pioneer has changed the way the volume works, where it wont let you turn it up to the point of clipping.

personally I am not a big fan of RF. They used to be known for quality amps, but I'm not sure what they are like now in terms of quality. If they are anything like their new subs then I would never buy them.

Here's a few amps that would power those speakers nicely:

http://www.cadencestore.com/ProductC...&idproduct=382

http://www.woofersetc.com/index.cfm?...roduct_ID=4287

http://www.woofersetc.com/index.cfm?...Product_ID=126

http://www.woofersetc.com/index.cfm?...Product_ID=189

http://www.woofersetc.com/index.cfm?...roduct_ID=3952

http://www.woofersetc.com/index.cfm?...roduct_ID=3113

http://www.woofersetc.com/index.cfm?...Product_ID=592

http://www.onlinecarstereo.com/CarAu...roductID=18377
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Old 10-31-2007, 12:44 PM
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Quote:
Originally Posted by oapy123 View Post

no offense but that is completely wrong. In his situation it has everything to do with it. He probably mounted the radio using a plastic dash kit, meaning the only connection to the chassis the radio has is through the antenna. If that is the case there will be a severe lack in performance.


With all due respect, and with gifty's findings, I am correct. I've installed a LOT of stereo systems in my day (16 years exp), with my last system pushing around 2000w RMS. I know exactly what 22w from a HU will do, and what 50w from a quality amp will do. Those MBQ's are power hungry, and you're simply not going to get high volume out of them from a HU. An 86db sensitivity rating is low for front speakers, and is indicative of needing an outboard power amp, hence the 50w RMS minimum rating on the speakers...

****

Understandably, people's interpretation of volume varies. For the time being, you can probably get a little more efficient use of your HU by keeping the loudness off and reducing the bass (I know it sucks, but it's worse if you can't hear anything). I do happen to have an old Rockford Fosgate amp for sale. It's a little scratched and one of the bass or treble knobs broke off (it's still hanging on though and can be superglued back if one were to open the chassis). But it works fine and will give you all the power you need and can drive an additional sub if you wanted to go that route in the future. It's a Punch 4080dsm (40x4 rms; 64x4 rms actual I think), bridgeable w/ built in crossovers, and I have the manual and birthsheet for it. PM me if you're interested.
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Old 10-31-2007, 02:31 PM
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Originally Posted by Lazonby View Post

With all due respect, and with gifty's findings, I am correct. I've installed a LOT of stereo systems in my day (16 years exp), with my last system pushing around 2000w RMS. I know exactly what 22w from a HU will do, and what 50w from a quality amp will do. Those MBQ's are power hungry, and you're simply not going to get high volume out of them from a HU. An 86db sensitivity rating is low for front speakers, and is indicative of needing an outboard power amp, hence the 50w RMS minimum rating on the speakers...

****

Understandably, people's interpretation of volume varies. For the time being, you can probably get a little more efficient use of your HU by keeping the loudness off and reducing the bass (I know it sucks, but it's worse if you can't hear anything). I do happen to have an old Rockford Fosgate amp for sale. It's a little scratched and one of the bass or treble knobs broke off (it's still hanging on though and can be superglued back if one were to open the chassis). But it works fine and will give you all the power you need and can drive an additional sub if you wanted to go that route in the future. It's a Punch 4080dsm (40x4 rms; 64x4 rms actual I think), bridgeable w/ built in crossovers, and I have the manual and birthsheet for it. PM me if you're interested.

take it easy man i'm not doubting your experience. I know a little something about stereo systems too (MECP certified, db drag competitor, broke 150db with a single 18" RE MT and Orion 2500d). 9/10 those symptoms are that of a bad ground. I've installed many a pair of high end speakers (better quality/higher power handling than those MB quarts...not that MB Quarts are bad) coupled with high end decks that put Pioneer to shame and even those setups would distort at full head unit volume. If he's not hearing any distortion its because the head unit is not clipping at full volume which is something I have never seen before. Even if he cut out all the lower frequencies it should still sound distorted. Or at least thats my experience.
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Old 11-06-2007, 07:28 PM
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Originally Posted by oapy123 View Post

even if the speaker can handle more power, it should still be distorting at full volume. Thats really wierd. Maybe Pioneer has changed the way the volume works, where it wont let you turn it up to the point of clipping.

personally I am not a big fan of RF. They used to be known for quality amps, but I'm not sure what they are like now in terms of quality. If they are anything like their new subs then I would never buy them.

Here's a few amps that would power those speakers nicely:

http://www.cadencestore.com/ProductC...&idproduct=382

http://www.woofersetc.com/index.cfm?...roduct_ID=4287

http://www.woofersetc.com/index.cfm?...Product_ID=126

http://www.woofersetc.com/index.cfm?...Product_ID=189

http://www.woofersetc.com/index.cfm?...roduct_ID=3952

http://www.woofersetc.com/index.cfm?...roduct_ID=3113

http://www.woofersetc.com/index.cfm?...Product_ID=592

http://www.onlinecarstereo.com/CarAu...roductID=18377

Don't steer him to UnauthorizedKiddieCarStereo.com, AKA Woofersetc. These guys are notorious for either being unauthorized outright or transshipping, which is a good way to lose authorization for what they are legal for. "One year Woofersetc. online warranty" is all you need to know. These guys are sheisters.

And yes, even a good 5-channel amp will make a great difference, and allow for a subwoofer. How you aren't getting distortion now though is a true mystery. That will be all in the past when you add true current to your setup.

The First Clarke Law states, 'If an elderly but distinguished scientist says that something is possible he is almost certainly right, but if he says that it is impossible he is very probably wrong.'
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Old 11-07-2007, 12:17 AM
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Originally Posted by oapy123 View Post

take it easy man i'm not doubting your experience. I know a little something about stereo systems too (MECP certified, db drag competitor, broke 150db with a single 18" RE MT and Orion 2500d). 9/10 those symptoms are that of a bad ground. I've installed many a pair of high end speakers (better quality/higher power handling than those MB quarts...not that MB Quarts are bad) coupled with high end decks that put Pioneer to shame and even those setups would distort at full head unit volume. If he's not hearing any distortion its because the head unit is not clipping at full volume which is something I have never seen before. Even if he cut out all the lower frequencies it should still sound distorted. Or at least thats my experience.

I totally agree with you. My only guess is that his definition of distortion isn't clipping, but actually loud mechanical noises? If that is true then I can see how the head unit doesn't have enough power to drive the speaker to it's mechanical peaks.

The solution is rather simple. The head unit doesn't have enough power to run the speakers, which isn't too surprising. This is especially true if the speakers are being drowned out by a subwoofer. Add an outboard amplifier and you will get the output you want, not to mention much better sound. I personally dislike the sound of deck power.

The other possibility is that the speakers impedance is really high and not loading the head unit to it's max. That is rather unlikely with MB Quart speakers though. These aren't 8 or 16 ohm drivers, are they?
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Old 11-07-2007, 09:20 AM
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Quote:
Originally Posted by Lazonby View Post

There are two major types of energy sources in car audio: high power and high current. Generally speaking, high power produces the watts, but when placed under a heavy load (heavy load = low impedance), they fail because of the lack of current capability.

This statement seems to be a little off. Power is measured in watts, it doesn't produce watts. And current times voltage is power (P=E*I). Based on that formula a higher current amp would produce more power unless limited by voltage.

The problem here comes from the fact that not all 4 ohm speakers produce the same load on an amplifier. This is because the 4 ohm rating is a rounded off figure and doesn't accurately represent the actual lowest impedance of the driver. To get a better comparison of two drivers you can look at the DC resistance of the drivers (Re). The impedance can never drop below the DC resistance as it is a part of the impedance. So it can be used to compare what kind of load to expect. You will find that higher end speakers will have a lower DCR than cheap coaxial speakers. This is why they are never as loud and cause the head unit amplifier to clip sooner.
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