Is 0.03% THD a lot of distortion for a bridged amp?
Replies (14)
swez on 08/11/2005 21:36:26
At rated power, this is a very low distortion amp. Most human ears cannot detect a THD below ~3.0%.
Swez
Buickman94 on 08/11/2005 23:40:58
Below 3% in bass, that is ;-)...
Victor on 08/12/2005 03:26:26
All you need to know about THD.
http://www.dogstar.dantimax.dk/tubestuf/thdconv.htm
http://www.sengpielaudio.com/calculator-thd.htm
I doubt if all of us out here would like to read a long and detailed paper, but this sure will give u an in-depth understanding of THD.
Hope that helps..
Victor...
MrBrownstone on 08/12/2005 16:09:55
Here's the skinny.
All electronice devices put out distortion. Distortion is basically output that doesn't match the input. Ex:
INPUT:
Swez is my Hero
OUTPUT:
Swez is my Heroine
Basically, when an amplification device makes output, there is always noise that is produce by the amplifier that wasn't in the original recording.
THD rating is basically a reference point. ex:
Swez runs 4.4 seconds
Mr B runs 4.25 seconds
THD would be at what distance. 40 yards, 40 feet, etc.
An amplifier that is accurately rated at 100W x1 @ 1% distortion is the same as every other ACCURATELY rate amplifier. Keep in mind that once an amplifier begins to clip/distort, it's distortion goes up rapidly. 100W @ 1% THD might be 110W @ 8% THD...Basically, as your amplifier goes up in power, not much more than the original 100W becomes music...the extra power is distortion because you've reached the maximum of the amplifier.
As long as it's from a reputable company, 0.3% THD vs 1% THD ratings don't really matter. What does is the power output and what you pay. a 100Wx1 @ 0.3% THD vs a 100Wx1 @ 1% THD is basically going to sound the same. In all reality, @ 0.3% THD, the 2nd amplifier probably put out 96watts...and they just wanted to make it an even 100W for marketing purposes....
In either case, neither amp is superior. Until you got to, say 125 to 130 watts, you probably wouldn't be able to significantly hear the difference between the products...particularly subwoofer output, which sucks a lot of juice. A better comparison would be between a 600 & 750W amplifier.....only a minor difference.
unloco on 08/12/2005 21:07:52
14.4V RMS Bridged (0.3% THD) 130Wx2
12V RMS Bridged (0.3% THD) 90Wx2
Alpine MRV-F340
This is what the website states about this amp. I was asking the question because when I called Alpine a couple of years ago to ask if it would be OK to run two speakers off this amp they basicly told me it would be to much THD. I'm putting it in a new truck and wanted to hook up only two speakers up front and bridge this amp. So with all that said I thank you all for your input and I guess it's OK to hook up two speakers to this amp
ttocs on 08/12/2005 22:09:43
it is made to run two speakers, thd would have no area in selecting this amp.
What two speakers up front are you wanting to bridge?
swez on 08/13/2005 11:23:09
Hummmm, once again, Mr. B. is my go to guy! Heroine, never touch the stuff.
This amp is great for power full range or woofers. If you bridge the amp, will double the output wattage, but need a net 4 ohm load or higher, when bridged.
I see no reason to bridge this amp for front speakers. It has adequate power to run all but the strongest full range Components or Coaxial systems out there.
Swez
unloco on 08/13/2005 15:04:32
•14.4V RMS Continuous Power 2ohm; Stereo (0.3% THD) 65Wx4 4ohm; Bridged (0.3% THD) 130Wx2
• 12V RMS Continuous Power 4ohm; Stereo (0.08% THD) 35Wx4 2ohm; Stereo (0.3% THD) 45Wx4 4ohm; Bridged (0.3% THD) 90Wx2
These are all the specs for this amp. My setup in my S10 was two Alpine SPX-177A mounted in the doors and two CDT 5 1/4 inch mounted in the kick panels with MRV-F340 powering them and a seperate amp powering a sub woofer. All four speakers were up front. I was hoping to run just two speakers thru the bridged amp and get about the same results. Should I just buy a new set of Kick panels and run the same setup in the Tahoe?
swez on 08/14/2005 10:42:27
Got it, this is a 4 channel amp. (F340) Now I see why you wish to bridge it. Let's break it down a bit here:
1. SPX-177R are 75 watts RMS (4 ohms)
2. CDT 5.25" MB are 4 ohms
3. F340 is a 4 channel amp (35 x 4 @ 4 ohms)
How well do the 177R's perform w/o the CDT's? More power to them (177R's) will definitely help bring up the MB punch. This would lead me to bridge the F340 to a 2 channel and run only the 177R's off this amp. The amp is a bit strong for them when bridged, but you can compensate with the gain adjustments or installing attenuators at the input stage of the amp. (F-Mod attenuators from Harrison Labs are great for this purpose) These depend on the HU RCA voltage you have available to drive your amps.
As for the CDT's, which model # are you using here? They like power too. To get the most from them, best if they are also amped, with a band pass filteron them. Can give you more details after more input on the model and how you wish to use them.
Swez
unloco on 08/14/2005 12:17:05
First I'd like to say Thank you Swez and all others who have replied here. I really appreciate the help. Now, I have a Eclipse CD8445 which has 8V at the preouts. I was trying to eliminate the CDT'S all together (they are the classic line see below for specs) just to make things easier. I'm not sure what a attenuator is but if you say i need them I'll put them in if they don't cost too much. Will I blow my speakers if I don't put them in? The whole system in my S10 sounded great. I haven't tryed running the 177's thru the bridged amp so I'll probably try them alone first and then if i don't like the sound I may buy another 2 channel amp for the CDT's and put them back in. What do you think? Thanks, Tim
CL-51
5.25" 2-Way
Midrange: 5.25"
Crossover: "Phase Perfect" Elliptic 4th
order 2-Way SatNat-456a
Tweeter: 1" silk soft dome
Power Handling: 80 watt RMS
Frequency Response: 65-20kHz
Sensitivity: 91.5 dB
Impedance: 4Ohm
swez on 08/15/2005 10:04:44
Am a bit confused here... say you have a pair of Alpine SPX-177R's (2-way Component set) and also a CL-51 Comp set up front?
If I read your install correctly, the Alpine's MB/MR dirvers are in door and the tweets in "A" pillars?
But when the CDT's are mentioned, not sure if you are only using the 5.25" driver or the whole component kit here??? Please clarify what you wish to do and then I can walk you through some options.
Swez
unloco on 08/15/2005 15:32:04
You read it right. I had everything up front. I was running the complete set of CDT components. I had both pieces(mid and tweet) mounted in Q-Logic kick panels and was running them as rear speakers.I also had the extra set of CDT tweeters mounted on the dash as close to the windshield as possible. I'm trying to eleminate them because I'd have to buy a new set of Q-Logic kick panels for the Tahoe. You pretty much answered my questions that it will be alright to run the Alpine 177's thru a bridged F340 amp with the gain turned down.
swez on 08/15/2005 18:10:35
OK, we are on the same page now. What I would suggest here, run only 1 set of Comps up front on your Tahoe. The Alpine's are fine, since they are already there. The F340 amp can be bridged for more power and set your gains at 4.0 volts. Start with the HPF crossover settings between 60 - 80 Hz.
Since the HU can deliver up to 8.0 volts, you may need a 3dB attenuator kit to balance HU output to the F340 amp. Or, just use less HU volume intelligently to prevent overdriving the amp input stage.
The CDT's would make a nice set of rear fills in this vehicle, if you have a spot for them. For best results, amping them too, is definitely a plus. A solid 2 channel amp will do the job well here. Figure 50 watts RMS/channel @ 4 ohms as a minimum and maybe 80-100 Wrms/channel as a max. Cross these over above 80 Hz., with a HPF. Depending on how the 5.25's can handle power and lows, may have to raise that crossover point a tad.
As for a bass machine to complete the deal, what do you have in mind?
Swez
unloco on 08/15/2005 18:45:39
I have a Alpine Bandpass 10" 1041BP sub running thru a MRD-M300 amp
Replies (14)
swez on 08/11/2005 21:36:26
At rated power, this is a very low distortion amp. Most human ears cannot detect a THD below ~3.0%.
Swez
Buickman94 on 08/11/2005 23:40:58
Below 3% in bass, that is ;-)...
Victor on 08/12/2005 03:26:26
All you need to know about THD.
http://www.dogstar.dantimax.dk/tubestuf/thdconv.htm
http://www.sengpielaudio.com/calculator-thd.htm
I doubt if all of us out here would like to read a long and detailed paper, but this sure will give u an in-depth understanding of THD.
Hope that helps..
Victor...
MrBrownstone on 08/12/2005 16:09:55
Here's the skinny.
All electronice devices put out distortion. Distortion is basically output that doesn't match the input. Ex:
INPUT:
Swez is my Hero
OUTPUT:
Swez is my Heroine
Basically, when an amplification device makes output, there is always noise that is produce by the amplifier that wasn't in the original recording.
THD rating is basically a reference point. ex:
Swez runs 4.4 seconds
Mr B runs 4.25 seconds
THD would be at what distance. 40 yards, 40 feet, etc.
An amplifier that is accurately rated at 100W x1 @ 1% distortion is the same as every other ACCURATELY rate amplifier. Keep in mind that once an amplifier begins to clip/distort, it's distortion goes up rapidly. 100W @ 1% THD might be 110W @ 8% THD...Basically, as your amplifier goes up in power, not much more than the original 100W becomes music...the extra power is distortion because you've reached the maximum of the amplifier.
As long as it's from a reputable company, 0.3% THD vs 1% THD ratings don't really matter. What does is the power output and what you pay. a 100Wx1 @ 0.3% THD vs a 100Wx1 @ 1% THD is basically going to sound the same. In all reality, @ 0.3% THD, the 2nd amplifier probably put out 96watts...and they just wanted to make it an even 100W for marketing purposes....
In either case, neither amp is superior. Until you got to, say 125 to 130 watts, you probably wouldn't be able to significantly hear the difference between the products...particularly subwoofer output, which sucks a lot of juice. A better comparison would be between a 600 & 750W amplifier.....only a minor difference.
unloco on 08/12/2005 21:07:52
14.4V RMS Bridged (0.3% THD) 130Wx2
12V RMS Bridged (0.3% THD) 90Wx2
Alpine MRV-F340
This is what the website states about this amp. I was asking the question because when I called Alpine a couple of years ago to ask if it would be OK to run two speakers off this amp they basicly told me it would be to much THD. I'm putting it in a new truck and wanted to hook up only two speakers up front and bridge this amp. So with all that said I thank you all for your input and I guess it's OK to hook up two speakers to this amp
ttocs on 08/12/2005 22:09:43
it is made to run two speakers, thd would have no area in selecting this amp.
What two speakers up front are you wanting to bridge?
swez on 08/13/2005 11:23:09
Hummmm, once again, Mr. B. is my go to guy! Heroine, never touch the stuff.
This amp is great for power full range or woofers. If you bridge the amp, will double the output wattage, but need a net 4 ohm load or higher, when bridged.
I see no reason to bridge this amp for front speakers. It has adequate power to run all but the strongest full range Components or Coaxial systems out there.
Swez
unloco on 08/13/2005 15:04:32
•14.4V RMS Continuous Power 2ohm; Stereo (0.3% THD) 65Wx4 4ohm; Bridged (0.3% THD) 130Wx2
• 12V RMS Continuous Power 4ohm; Stereo (0.08% THD) 35Wx4 2ohm; Stereo (0.3% THD) 45Wx4 4ohm; Bridged (0.3% THD) 90Wx2
These are all the specs for this amp. My setup in my S10 was two Alpine SPX-177A mounted in the doors and two CDT 5 1/4 inch mounted in the kick panels with MRV-F340 powering them and a seperate amp powering a sub woofer. All four speakers were up front. I was hoping to run just two speakers thru the bridged amp and get about the same results. Should I just buy a new set of Kick panels and run the same setup in the Tahoe?
swez on 08/14/2005 10:42:27
Got it, this is a 4 channel amp. (F340) Now I see why you wish to bridge it. Let's break it down a bit here:
1. SPX-177R are 75 watts RMS (4 ohms)
2. CDT 5.25" MB are 4 ohms
3. F340 is a 4 channel amp (35 x 4 @ 4 ohms)
How well do the 177R's perform w/o the CDT's? More power to them (177R's) will definitely help bring up the MB punch. This would lead me to bridge the F340 to a 2 channel and run only the 177R's off this amp. The amp is a bit strong for them when bridged, but you can compensate with the gain adjustments or installing attenuators at the input stage of the amp. (F-Mod attenuators from Harrison Labs are great for this purpose) These depend on the HU RCA voltage you have available to drive your amps.
As for the CDT's, which model # are you using here? They like power too. To get the most from them, best if they are also amped, with a band pass filteron them. Can give you more details after more input on the model and how you wish to use them.
Swez
unloco on 08/14/2005 12:17:05
First I'd like to say Thank you Swez and all others who have replied here. I really appreciate the help. Now, I have a Eclipse CD8445 which has 8V at the preouts. I was trying to eliminate the CDT'S all together (they are the classic line see below for specs) just to make things easier. I'm not sure what a attenuator is but if you say i need them I'll put them in if they don't cost too much. Will I blow my speakers if I don't put them in? The whole system in my S10 sounded great. I haven't tryed running the 177's thru the bridged amp so I'll probably try them alone first and then if i don't like the sound I may buy another 2 channel amp for the CDT's and put them back in. What do you think? Thanks, Tim
CL-51
5.25" 2-Way
Midrange: 5.25"
Crossover: "Phase Perfect" Elliptic 4th
order 2-Way SatNat-456a
Tweeter: 1" silk soft dome
Power Handling: 80 watt RMS
Frequency Response: 65-20kHz
Sensitivity: 91.5 dB
Impedance: 4Ohm
swez on 08/15/2005 10:04:44
Am a bit confused here... say you have a pair of Alpine SPX-177R's (2-way Component set) and also a CL-51 Comp set up front?
If I read your install correctly, the Alpine's MB/MR dirvers are in door and the tweets in "A" pillars?
But when the CDT's are mentioned, not sure if you are only using the 5.25" driver or the whole component kit here??? Please clarify what you wish to do and then I can walk you through some options.
Swez
unloco on 08/15/2005 15:32:04
You read it right. I had everything up front. I was running the complete set of CDT components. I had both pieces(mid and tweet) mounted in Q-Logic kick panels and was running them as rear speakers.I also had the extra set of CDT tweeters mounted on the dash as close to the windshield as possible. I'm trying to eleminate them because I'd have to buy a new set of Q-Logic kick panels for the Tahoe. You pretty much answered my questions that it will be alright to run the Alpine 177's thru a bridged F340 amp with the gain turned down.
swez on 08/15/2005 18:10:35
OK, we are on the same page now. What I would suggest here, run only 1 set of Comps up front on your Tahoe. The Alpine's are fine, since they are already there. The F340 amp can be bridged for more power and set your gains at 4.0 volts. Start with the HPF crossover settings between 60 - 80 Hz.
Since the HU can deliver up to 8.0 volts, you may need a 3dB attenuator kit to balance HU output to the F340 amp. Or, just use less HU volume intelligently to prevent overdriving the amp input stage.
The CDT's would make a nice set of rear fills in this vehicle, if you have a spot for them. For best results, amping them too, is definitely a plus. A solid 2 channel amp will do the job well here. Figure 50 watts RMS/channel @ 4 ohms as a minimum and maybe 80-100 Wrms/channel as a max. Cross these over above 80 Hz., with a HPF. Depending on how the 5.25's can handle power and lows, may have to raise that crossover point a tad.
As for a bass machine to complete the deal, what do you have in mind?
Swez
unloco on 08/15/2005 18:45:39
I have a Alpine Bandpass 10" 1041BP sub running thru a MRD-M300 amp
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