Hey guys i am pretty new to car audio and after reading just about every article on the site and a few topics in the forums I am a little more informed but i still have a handful of questions.
I was having an occasional problem with my system which after reading Swez's very informative artical i think is clipping. I do not have any amplifiers yet. I put an Alpine CDA-9813 which is 60 watts by 4 channels. I made what i now see as a mistake of buying speakers which can handle mroe than this and got Infinity Perfect 6 and 1/2 75 for the rear which can handle 75 watts per speaker, and pioneer 5 way 6x9s for the front which can handle 80 watts per speaker. I figured i would be safe adn go with speaker that could handle a little bit extra. Well sometimes when i am cranking it up the system will all of a sudden have extreme distortion and can only be stopped by turning it down and then the music is very quite compared to what it usually is for that volume. I figured this was clipping but i just wanted to double check.
I have plenty of other questions but i suppose i will wait for another day, one thing at a time....
Replies (5)
swez on 04/6/2004 08:20:23
Yes, I think you have a correct diagnosis here. Using too much boost on the tone controls (over EQing) will cause any HU to clip much sooner and at lower power settings. The amps in the HU are just gassing out and clipping... bad for speakers!
Most HU's are rated at peak watts output. You said 60 x 4 in this case right? Well, the RMS power is 27 watts per channel into a 4 ohm speaker. This HU also has a need for a #10 gage power feed wire to carry proper current to the HU. If you used a smaller gage wire, the HU can be starving for power.
Important Note: The powerful output of Alpine's V-Drive internal amplifier requires a direct fused connection to your vehicle's battery! We recommend that you purchase a 10-gauge amp wiring kit with this receiver.
Wiring Notes:
Wiring Note: While providing high power output, this unit can draw a substantial amount of current. Per Alpine, this receiver's constant power wire must be connected directly to the positive terminal of the battery in your vehicle, and 10-gauge wire must be used to make the connection. This requires a length of 10-gauge power cable, an in-line fuse holder with a 20- to 30-amp fuse and a ring terminal (the ring terminal is used to connect the cable to the battery clamp). Although all the pieces of a basic amplifier wiring kit will not be not needed, if you do not wish to assemble the required items separately, the power wire and in-line fuse holder from a basic 10-gauge kit can be used to connect the constant power wire to your vehicle's battery. For a secure, permanent connection, the 10-gauge cable must be soldered to this receiver's 16-gauge constant power wire.
The wiring and power notes came from Crutchfield's product links.
http://www.crutchfield.com/S-CEruBCKjrkb/cgi-bin/ProdView.asp?a=&s=0&cc=01&g=62700&id=detailed_info&i=500CDA9813
This is a nice HU and has some very nice features too. The best part of this HU is the preamp outputs for outboard amping. This HU has 4 volt RCA outputs: L&R front, L&R rear and sub outs.
Adding a decent 4 channel amp will definitely improve performance and clarity of sound at higher listening levels. The rear speakers are a nice choice, but you may find the Pioneer front speakers to be very out of balance in terms of harsh mids and shrill highs. Most 6x9 mounts can be adapted to using 6.5" coaxials or Component style speakers. These would be superior in sound quality to most 6x9's I have listen to over the years. A matching set of Perfects up front would be a very good option, along with a modest (50-75 x 4 RMS watts) 4 channel amp to drive them.
Many of us like the USB-4065 or -4085 for price, performance and value.
Look: http://www.crutchfield.com/S-CEruBCKjrkb/cgi-bin/prodview.asp?s=0&cc=01&i=235USB4085&g=120
Swez
eldevioso on 04/8/2004 16:32:30
This is very interesting. I had no idea that some of the decks required direct power sourcing.
Is this a new trend? Would it apply to my past setups running 40w/ch with aftermarket decks? I mean, although these older decks didn't specifically mention a direct power feed, would it have helped their performance if I wired them such?
Further, is this the norm with good installers to have a true power source to the receiver or am I looking into this too deeply?
swez on 04/8/2004 19:27:41
Alpine an perhaps a few other HU makers have been experimenting with higher output Mosfet HUs. They draw more current/watts to achieve this, so a larger gage direct wire power feed is employed.
If I understand what they are doing here, it is a special power supply in the HU that kicks up the HU voltage available to the internal amplifiers. That in turn, provides a few more watts of output from a HU that uses this concept.
The only real issue I see... a designer can only pull so many watts out of a small internal amp set. (4 channels in this case) If you want some real power (50 watts RMS or more) to drive internal speakers to full potential, the only option is outboard amplification.
That's pretty much the nuts and bolts of this concept. For the casual listener who wants better than stock performance, this is a good option without ripping the vehicle apart. (leased car owners)
Swez
only_tuning on 04/10/2004 19:14:36
so does this apply on all alpines HU's THINK ?????????br
swez on 04/11/2004 09:46:30
Nope... there are a few amps in the Alpine line that have that feature. It's a limited number of HU's with that feature.
It sound like a great idea... but if you run some calculations, it is easy to see that there is very little benefit. Everytime we double the watts input to a speaker, we get a +3dB increase in SPL.
Here are some parameters to consider:
1watt input (2.0 volts/4 ohm)
1 meter distance from driver
Test done in free air, anechoic chamber
Calibrated test equipment
Test tone generator (100 & 1,000 Hz)
Watts input: ............Speaker Eff: 87 fixed...............SPL Output:
1 watt...............................87......................................87 dB
2 watts.......................................................................90 dB
4 watts.......................................................................93 dB
8 watts.......................................................................96 dB
16 watts.....................................................................99 dB
32 watts...................................................................102 dB
64 watts...................................................................105 dB
132 watts.................................................................108 dB
264 watts.................................................................111 dB
Now, this is a set of numbers that does not account for cabin gain or enclosure gain effects.
Hope this helps others understand the relationship between input power, speaker efficiency ratings and SPL output.
Swez
I was having an occasional problem with my system which after reading Swez's very informative artical i think is clipping. I do not have any amplifiers yet. I put an Alpine CDA-9813 which is 60 watts by 4 channels. I made what i now see as a mistake of buying speakers which can handle mroe than this and got Infinity Perfect 6 and 1/2 75 for the rear which can handle 75 watts per speaker, and pioneer 5 way 6x9s for the front which can handle 80 watts per speaker. I figured i would be safe adn go with speaker that could handle a little bit extra. Well sometimes when i am cranking it up the system will all of a sudden have extreme distortion and can only be stopped by turning it down and then the music is very quite compared to what it usually is for that volume. I figured this was clipping but i just wanted to double check.
I have plenty of other questions but i suppose i will wait for another day, one thing at a time....
Replies (5)
swez on 04/6/2004 08:20:23
Yes, I think you have a correct diagnosis here. Using too much boost on the tone controls (over EQing) will cause any HU to clip much sooner and at lower power settings. The amps in the HU are just gassing out and clipping... bad for speakers!
Most HU's are rated at peak watts output. You said 60 x 4 in this case right? Well, the RMS power is 27 watts per channel into a 4 ohm speaker. This HU also has a need for a #10 gage power feed wire to carry proper current to the HU. If you used a smaller gage wire, the HU can be starving for power.
Important Note: The powerful output of Alpine's V-Drive internal amplifier requires a direct fused connection to your vehicle's battery! We recommend that you purchase a 10-gauge amp wiring kit with this receiver.
Wiring Notes:
Wiring Note: While providing high power output, this unit can draw a substantial amount of current. Per Alpine, this receiver's constant power wire must be connected directly to the positive terminal of the battery in your vehicle, and 10-gauge wire must be used to make the connection. This requires a length of 10-gauge power cable, an in-line fuse holder with a 20- to 30-amp fuse and a ring terminal (the ring terminal is used to connect the cable to the battery clamp). Although all the pieces of a basic amplifier wiring kit will not be not needed, if you do not wish to assemble the required items separately, the power wire and in-line fuse holder from a basic 10-gauge kit can be used to connect the constant power wire to your vehicle's battery. For a secure, permanent connection, the 10-gauge cable must be soldered to this receiver's 16-gauge constant power wire.
The wiring and power notes came from Crutchfield's product links.
http://www.crutchfield.com/S-CEruBCKjrkb/cgi-bin/ProdView.asp?a=&s=0&cc=01&g=62700&id=detailed_info&i=500CDA9813
This is a nice HU and has some very nice features too. The best part of this HU is the preamp outputs for outboard amping. This HU has 4 volt RCA outputs: L&R front, L&R rear and sub outs.
Adding a decent 4 channel amp will definitely improve performance and clarity of sound at higher listening levels. The rear speakers are a nice choice, but you may find the Pioneer front speakers to be very out of balance in terms of harsh mids and shrill highs. Most 6x9 mounts can be adapted to using 6.5" coaxials or Component style speakers. These would be superior in sound quality to most 6x9's I have listen to over the years. A matching set of Perfects up front would be a very good option, along with a modest (50-75 x 4 RMS watts) 4 channel amp to drive them.
Many of us like the USB-4065 or -4085 for price, performance and value.
Look: http://www.crutchfield.com/S-CEruBCKjrkb/cgi-bin/prodview.asp?s=0&cc=01&i=235USB4085&g=120
Swez
eldevioso on 04/8/2004 16:32:30
This is very interesting. I had no idea that some of the decks required direct power sourcing.
Is this a new trend? Would it apply to my past setups running 40w/ch with aftermarket decks? I mean, although these older decks didn't specifically mention a direct power feed, would it have helped their performance if I wired them such?
Further, is this the norm with good installers to have a true power source to the receiver or am I looking into this too deeply?
swez on 04/8/2004 19:27:41
Alpine an perhaps a few other HU makers have been experimenting with higher output Mosfet HUs. They draw more current/watts to achieve this, so a larger gage direct wire power feed is employed.
If I understand what they are doing here, it is a special power supply in the HU that kicks up the HU voltage available to the internal amplifiers. That in turn, provides a few more watts of output from a HU that uses this concept.
The only real issue I see... a designer can only pull so many watts out of a small internal amp set. (4 channels in this case) If you want some real power (50 watts RMS or more) to drive internal speakers to full potential, the only option is outboard amplification.
That's pretty much the nuts and bolts of this concept. For the casual listener who wants better than stock performance, this is a good option without ripping the vehicle apart. (leased car owners)
Swez
only_tuning on 04/10/2004 19:14:36
so does this apply on all alpines HU's THINK ?????????br
swez on 04/11/2004 09:46:30
Nope... there are a few amps in the Alpine line that have that feature. It's a limited number of HU's with that feature.
It sound like a great idea... but if you run some calculations, it is easy to see that there is very little benefit. Everytime we double the watts input to a speaker, we get a +3dB increase in SPL.
Here are some parameters to consider:
1watt input (2.0 volts/4 ohm)
1 meter distance from driver
Test done in free air, anechoic chamber
Calibrated test equipment
Test tone generator (100 & 1,000 Hz)
Watts input: ............Speaker Eff: 87 fixed...............SPL Output:
1 watt...............................87......................................87 dB
2 watts.......................................................................90 dB
4 watts.......................................................................93 dB
8 watts.......................................................................96 dB
16 watts.....................................................................99 dB
32 watts...................................................................102 dB
64 watts...................................................................105 dB
132 watts.................................................................108 dB
264 watts.................................................................111 dB
Now, this is a set of numbers that does not account for cabin gain or enclosure gain effects.
Hope this helps others understand the relationship between input power, speaker efficiency ratings and SPL output.
Swez
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