Amp suggestions for 10" Phoenix Gold RSDC10-4

[gunz4me2 10+ year member]

By nature of its design, a loudspeaker is the largest waster of power by converting it to heat, undistorted or distorted.

Also what percentage of distortion must an amplifier reach in order to produce enough heat or DC voltage to cook a woofer? I ask because in my short history of owning an oscilloscope, 12v power supply, dummy loads, and a Fluke 117, I can't recall any torture test where a slight amount of clipping caused ANY amplifier tested on my bench to output a significant amount of DC that would ruin a driver. I guess I will check again with the Orion HCCA 225 Digital Reference that I am in the process of repairing, but I am not expecting the results to be any different. Come to think of it, maybe I need to add a distortion analyzer to my toy collection. //content.invisioncic.com/y282845/emoticons/biggrin.gif.d71a5d36fcbab170f2364c9f2e3946cb.gif

Then again, maybe I am giving too many individuals the benefit of the doubt by assuming that they know better than to overdrive the bejesus out of their amplifier while pushing nearly 40% distortion to their speakers.

Lastly, if an amplifier produces 1% distortion, like my Clarion DPX1851 is claiming to do on paper, and that higher distortion number kills subwoofers, why isn't my subwoofer dead?

Disclaimer: I am not an electrical engineer in real life nor do I pretend to be one on the internet. I am just a hobbyist/enthusiast who has more money than sense and the longing to learn as much as I can about whatever hobby of the moment I am involved in!

 

[VWBobby 10+ year member]

If you want a decent amp that can do a little more than rated power for ~$200, the MB Quart DSC1500.1D or ONX1500.1D. The Sundown or AudioQue 1200-watt amps are also good, and the prices are a little higher.

Clipping causes DC voltage which can overheat the subwoofer coils. SOME subwoofers are rated on RMS Music power, which is dynamic AC power. This is not to be confused with "nominal" or average power.... I'm talking about ratings that are on AC voltage. If the subwoofer is being operated with clean AC power, the cone travel will be linear and precise. This helps cool the coil by moving it in fresh air and working the cooling ports on the motor of the sub (if equipped). If you power a sub with DC voltage of the same amount, you may reach excursion (depending on voltage/amperage) with no reciprocal motion. //content.invisioncic.com/y282845/emoticons/wink.gif.608e3ea05f1a9f98611af0861652f8fb.gif The subwoofer is a liner electric motor of sorts...If you hold it in 1 place with a DC voltage, even a low one, you will have to waste heat somehow. //content.invisioncic.com/y282845/emoticons/wink.gif.608e3ea05f1a9f98611af0861652f8fb.gif If you are below the thermal limits of the coil, you will be fine, above these limits obviously you'll have a burned coil. That's why you can do a clean "burp" with a high RMS AC signal (test tone) and not blow a sub. If you did the same test with a DC signal, same voltage/amperage, you would blow it well past the xmax or even thermal limits of the sub. This will demonstrate the difference between a damaging DC signal compared to a high powered, but clean, AC signal.

 

[tinmanchris217 10+ year member]

@ Mclerico

//content.invisioncic.com/y282845/emoticons/graduate.gif.d982460be9f153bb54e5d4cb744f6ae8.gif Go Bulls. I'm on CA.com instead of working on my Mech. E. thesis @ University of Houston

Your explanation is correct for the most part, but I'll clarify the designation between distortion and clipping.

Distortion is when unwanted harmonics appear. If you play a 100 Hz tone, and the amplifier may leak out a 200 Hz overtone. THD is a measure of how much junk gets added between the input and output.

Clipping is when the sine wave gets flattened, when the amplifier cant supply enough rail voltage. The flat top becomes a square wave, as clipping increases.

The same way a Fourier series can recreate a square wave using sine waves (the fundamental frequency plus the added overtones) ... so does the amplifier. You keep sending more power (area under the curve), but alot of this power is lost to heat, since the overtones are counteracting the fundamental cone movement. In the same way a sub will act when you wire dual voice coils opposingly. More input power without added cooling (convection). This is where the added heat comes from.

Summary:

Woofer death is usually due to overheating. Overheating is usually due to distortion created during clipping. Clipping is preventable... so don't be a dummy.

PS - I'm one of those poor souls who use Audiopipe amps. Ironically enough, I've abused them for a couple years of competition and World Finals. Now I'm using them in my SQ setup. When gains are set properly, 99% of class D amps will have indistinguishable SQ for sub-bass. Subwoofer distortion is not noticeable in modest quantities (

 

[AndyWood7 10+ year member]

haha. thanks for the input everybody.

Summary:

Woofer death is usually due to overheating. Overheating is usually due to distortion created during clipping. Clipping is preventable... so don't be a dummy.

very good sir.

 

[AndyWood7 10+ year member]

Trying to research a little, but what is the big difference with the newer digital amps?

 

[mclerico83 5,000+ posts]

@ Mclerico
//content.invisioncic.com/y282845/emoticons/graduate.gif.d982460be9f153bb54e5d4cb744f6ae8.gif Go Bulls. I'm on CA.com instead of working on my Mech. E. thesis @ University of Houston

Your explanation is correct for the most part, but I'll clarify the designation between distortion and clipping.

Distortion is when unwanted harmonics appear. If you play a 100 Hz tone, and the amplifier may leak out a 200 Hz overtone. THD is a measure of how much junk gets added between the input and output.

Clipping is when the sine wave gets flattened, when the amplifier cant supply enough rail voltage. The flat top becomes a square wave, as clipping increases.

The same way a Fourier series can recreate a square wave using sine waves (the fundamental frequency plus the added overtones) ... so does the amplifier. You keep sending more power (area under the curve), but alot of this power is lost to heat, since the overtones are counteracting the fundamental cone movement. In the same way a sub will act when you wire dual voice coils opposingly. More input power without added cooling (convection). This is where the added heat comes from.

Summary:

Woofer death is usually due to overheating. Overheating is usually due to distortion created during clipping. Clipping is preventable... so don't be a dummy.

PS - I'm one of those poor souls who use Audiopipe amps. Ironically enough, I've abused them for a couple years of competition and World Finals. Now I'm using them in my SQ setup. When gains are set properly, 99% of class D amps will have indistinguishable SQ for sub-bass. Subwoofer distortion is not noticeable in modest quantities (

i was not saying he would hear the difference, i was saying that it will be a cleaner signal, hence cleaner power to his sub, and yes go BULLS

 

[VWBobby 10+ year member]

Trying to research a little, but what is the big difference with the newer digital amps?

Class-D does not mean digital, contrary to the WiKi article. Its just the type of amplifier/power supply. Class D has a higher switching rate than a Class A, AB, B, BD amp. It is nearly off most of the time except during the actual bass/music hits. A typical A/B amp has a base current running all the time and 'switches' into class B during peaks and dips. This isn't exactly how the amps work, but it gives you a better idea.

Here is a link that explains it in detail: Audio Amplifier Classes — Reviews and News from Audioholics

 

[gunz4me2 10+ year member]

I'm waiting on the big brown truck to drop off a Stetsom V 1K5 H! I know it utilizes a Programmable IC, but I wonder if it is a true digital class D as it is advertised to be?

 

[AndyWood7 10+ year member]

Sorry, wasn't asking for differences between amp classes. More comparing Analog Class D to Digital Class D. They mention something about error control?

 

[AndyWood7 10+ year member]

MB Quart Onx not CEA 2006 certified?

 

[VWBobby 10+ year member]

I'm waiting on the big brown truck to drop off a Stetsom V 1K5 H! I know it utilizes a Programmable IC, but I wonder if it is a true digital class D as it is advertised to be?

That looks like a nice amp! Very small footprint for the power output, must be very efficient. I know the newer amps are using a "1 chip" type design for some of the preamp circuitry. I guess some of the chip makers are starting to come up with some all-in-one solutions for amplifier manufactures to make it simple and have less noise/higher efficiency.

One of the only things I know about the "digital" Class-D amps, they have a comparator that looks for errors or spikes in the output and reduces them. The music is actually running at a much higher frequency (modulation) and the amplifier has to bring it back down to the original frequency at the speaker terminals. I think the error correction is for any power supply ripple, flaw, etc that could introduce distortion or stray DC signals. //content.invisioncic.com/y282845/emoticons/wink.gif.608e3ea05f1a9f98611af0861652f8fb.gif

Similar to if you had no filtering on a large power amp.... any spikes in the AC line or source material will be amplified 10x in the power amplifier section (for example).

 

[gunz4me2 10+ year member]

That looks like a nice amp! Very small footprint for the power output, must be very efficient. I know the newer amps are using a "1 chip" type design for some of the preamp circuitry. I guess some of the chip makers are starting to come up with some all-in-one solutions for amplifier manufactures to make it simple and have less noise/higher efficiency.
One of the only things I know about the "digital" Class-D amps, they have a comparator that looks for errors or spikes in the output and reduces them. The music is actually running at a much higher frequency (modulation) and the amplifier has to bring it back down to the original frequency at the speaker terminals. I think the error correction is for any power supply ripple, flaw, etc that could introduce distortion or stray DC signals. //content.invisioncic.com/y282845/emoticons/wink.gif.608e3ea05f1a9f98611af0861652f8fb.gif

Similar to if you had no filtering on a large power amp.... any spikes in the AC line or source material will be amplified 10x in the power amplifier section (for example).

Since the weather is nasty as can be, I have to play with it on the test bench in the house. When it comes to amplification I am impressed. The only thing I don't care for is that noisy fan. Hopefully, my plans for a rear seat delete with the amp-rack under it will stifle most of my fan noise. After all, I have a few amps with fans that I plan on using in my rebuild later this year:

 

[whitedragon551 5,000+ posts]

PG Xenon 600.1 Will do your power at 1,2 or 4 ohms and can be had for cheap. I wouldnt touch that Audiocrap with a 10ft pole.

 

[AndyWood7 10+ year member]

How about a MB Quart ONX1.1000D vs a Sundown SAZ 1200D?

 

[AndyWood7 10+ year member]

I'm looking at a Soundstream DTR1.900D also.