# High voltage amps vs High current amps



## Deathjunior (Aug 2, 2011)

So I finally got my amps and speakers in hopefully installing them in the coming months check out the photo below, Anywho in the meantime I have some questions for my SQ installs High Voltage vs High current amps. Whats the downside to a high voltage amplifier aside from maby cost? High voltage examples being linear power HV 2.2's and the older PPI models.


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## nick650 (Feb 7, 2011)

what the hell are you talking about??????

Amps are all 14.4 volts and they all draw different amounts of current. Please explain to further help you.


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## Viggen (May 2, 2011)

possibly you mean high vs low current amps? I think that's what many SQ home people state class D stuff can't sound as good as a good class A amp, doesn't have the current.


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## nick650 (Feb 7, 2011)

Viggen said:


> possibly you mean high vs low current amps? I think that's what many SQ home people state class D stuff can't sound as good as a good class A amp, doesn't have the current.


What the hell are you talking about?


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## TrickyRicky (Apr 5, 2009)

*The Power Supply*
The purpose of the supply is to convert the auto's battery voltage to a higher voltage.* For example, if an amplifier is to produce 100 watts into a 4 ohm speaker, we need 20 volts RMS. This implies that we need about +/-28 volts. (20 volts R.M.S. = 28.28 volts peak). We call that the "rail" voltage.* Since the amplifier's output transistors cannot pull all the way up to this rail, we actually need a slightly higher voltage.

The process is to convert the 12 volts DC into AC, feed it to a transformer and convert it back to DC again.

Converting the 12 volt battery voltage to AC is simple, a PWM (pulse width modulator) IC feeds a bank of MOSFETS (MOSFETs are switching transistors perfectly suited for this task).
The 12 volt power is switched at a very high frequency, somewhere between 40 and 150 kHz. Slower switching speeds require a larger transformer, but high speeds have more switching loss. Advanced transformer core materials, faster rectifiers, and clever winding methods have enabled us to utilize very high frequencies. Some of today's better amplifiers have very small power supplies that produce enormous amounts of power.

*Regulated Power Supplies*
Most early audio amplifiers contained unregulated power supplies. Regulated supplies require very high quality filter capacitors (called "low ESR" capacitors), output chokes, and an optically isolated voltage feedback circuit. Regulation occurs by controlling the switching pulse width from 0 - 100% to compensate for changes in the battery and rail voltage. The same action occurs when the audio level increases. As the amplifier draws more power from the supply, the rail voltage drops. Again, the regulator circuitry senses this drop and responds with an increased pulse width.

The high frequency PWM waveform is rectified (converted to DC) and applied to the output filter choke and capacitors. This output of this circuit is the + and - DC rails that feed the power amplifier.

*Unregulated Power Supplies*
Unregulated power supplies are less expensive than regulated supplies. They do not require an output choke, voltage sense or isolation circuitry. Because the duty cycle is nearly 100%, capacitor ripple current is much lower in unregulated supplies. Lower ripple current requires less expensive capacitors throughout.

Often we hear that unregulated designs have more "headroom". That means that the amplifier will produce extra power during transients. Most home audio amplifiers employ unregulated power supplies. The power supplies in these amplifiers run at 60 Hz, thus the filter capacitors must be 200-500 times larger than those used in high frequency switchers. The extra capacitance in home audio amplifiers results in extra headroom. Headroom for anything other than very short transients simply doesn't exist in the unregulated designs. The following is an example of specifications for an unregulated vs. regulated amplifiers.

Unregulated designs have a higher supply voltage at low power, causing higher voltage on the output transistors. This reduces the amplifier's efficiency.

Small amplifiers (less than 100 watts) cannot justify the extra cost of the regulation circuitry, so we often see unregulated supplies in these amplifiers.
*The Amplifier Section, Class AB and A*
Class AB and A amplifiers are similar, so we'll discuss both here. Class AB amplifiers have transistors that pull up to the positive rail and transistors that pull down to the negative rail. This corresponds to the action of pushing the speaker cone out and in.

Class AB means that the output transistors do not always have current on them. For example, when the upper transistors are pulling up towards the positive rail (pushing the speaker out), there is no current in the lower transistors. When the output signal swings through zero, towards the negative rail, the output transistor must go through a transition from zero current to a non-zero current. The best analogy that I can think of is driving an old car with too much slop in the steering. As you go from one side of the road's crown to the other, the steering crosses a "dead" zone, and you tend to over-steer. Special temperature compensated bias circuitry reduces this dead zone, known as notch distortion. The figure below shows the output of a class AB amplifier with too little bias and the resulting distortion. Notch distortion increases at higher frequencies and low volume levels. Some modern designs have reduced this type of distortion to very low levels.

Class A means that every transistor is always conducting current. They are very similar to class AB amplifiers, but the bias circuitry is set so that there are very high currents in the output transistors. Because these amplifiers do not have this "dead zone', less feedback is required to achieve low distortion.

A 100 watt amplifier may dissipate nearly 100 watts internally even when there is no audio output. This type of design is impractical in the harsh auto environment. Many class A amplifiers pedaled for the automotive market are not really class A. They are huge power wasters in the home as well.


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## rc10mike (Mar 27, 2008)

Probably talking about high voltage amps like A/B that make their full power at 4 ohms and high current amps like D that make their power a 1 ohm, in that case there's already quite a few threads on it...


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## daishi100 (Aug 29, 2011)

Death junior 

I know what your talking about, you mean like a $120 power akoustic 2000w amp vs a $700 650.1 kicker amp. There was an awesome explanation of the differences in an offsite thread, I'll see if I can find it.


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## daishi100 (Aug 29, 2011)

Found it, http://www.diymobileaudio.com/forum...04-voltage-high-current-explanation-tips.html

It was on site my bad  awesome explanation though


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## ChrisB (Jul 3, 2008)

If you listen to modern day electronic music, I'd suggest using that high voltage amplifier for your mids and highs versus placing it on your subwoofer. My experience with high voltage amps used on a sub resulted in my drum and bass NOT having any bass as the amp cut out on me. When I contacted a certain someone and told him the problem I was having I was told "try listening to real music!"


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## TrickyRicky (Apr 5, 2009)

ChrisB said:


> If you listen to modern day electronic music, I'd suggest using that high voltage amplifier for your mids and highs versus placing it on your subwoofer. My experience with high voltage amps used on a sub *resulted in my drum and bas*s NOT having any bass as the amp cut out on me. When I contacted a certain someone and told him the problem I was having I was told "try listening to real music!"


:laugh::laugh::laugh: Did you try it? J/K Chris.:laugh:

Am assuming your listing to that techno stuff, whats it call again..... dub step.


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## ChrisB (Jul 3, 2008)

TrickyRicky said:


> :laugh::laugh::laugh: Did you try it? J/K Chris.:laugh:
> 
> Am assuming your listing to that techno stuff, whats it call again..... dub step.


I like some dubstep too, in moderation. Usually when I'm driving, I use music as background noise and I tend to listen to stuff that does not trigger any emotions. Leave it to me to be that "exception" to the norm.:laugh:

Then again, just yesterday I was rocking out to some Steve Miller Band... Does that qualify as "real music"?


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## Deathjunior (Aug 2, 2011)

Why do I feel like no one who has posted a reply knows who linear power is? I don't blame you at all since they are just now restarting production of thier product

However, no none of what you have stated is at all what I meant. 
Accept tricky ricky who explained the situation well.
I know the difference between pulse width modulated, and what a rail is and all the other things you guys seemed to ask. Maby this question is to out dated for most of those in today's world of amps. Anywho what the older model Linear Power HV amps had was a higher volt rail system they were a hand built amp that by converting the voltage of the inputs could produce massive amounts of power. They were rated at .0001 THD at very small voltages say 45 and 15. We have a 2 channel running in an Audi TT right now on 10 gauge wire pushing close to 200 rms per channel says our meter, and the output voltage is running around a 26. This is what i meant by high voltage. The amp is owned by and was installed by Richard of team linear power Region 6, 2010 world sq world champion. The bigger blue Linear power amps he has can run a vacuum cleaner... apparently its actually been tested.


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## TrickyRicky (Apr 5, 2009)

Chris have used LinearPower before, as a matter of fact he sold me nearly all his collection when he decided to switch to Lunar.

But I think your getting confused, rail voltage is where the high voltage is at, not at the speaker terminals. The 8002SW has about a 120 +/- rail voltage, the 2502IQ about 90v and the 5002IQ around 100-110 rail voltage. In order to run a vacuum from an amplifier you would have to tap into the bridge rectifier diode module and you will see how one side is negative and one side is positive (when using the ground) when you measure both you get the total voltage which can be very high. 

I've met Richard early this year and had the pleasure of meeting Jeri McCord (who actually design and engineer the 5002IQ and the Stroker subwoofer and other great products). 

The amplifier you got is a 2.2HV? Thats the same as the 2502IQ but has a few parts different but maily the same board and output transistors. The 2502IQ was my favorite (had 5 of them at one point) also the 5002IQ. Currently using a 4503IQ and am happy with its performance, never cut off no matter how hot the day was (and some days it was 108 degrees here in Oklahoma).

One neat thing about most Linear Power amps was that they could actually produce same power at either 4-ohms or 2-ohms stereo. This is accomplished by switching the tabs inside the amplifier. When the tabs are at "4" the toroid has a few more winds to produce a higher voltage, then when switched at "2" the toroid had less winds to produce about 10v less (one each side of the rail).


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## Deathjunior (Aug 2, 2011)

I'm happy at least someone gets it, but what would be the downside to an amp like a linear power, cause to be honest there not exactly crazy expensive, not compared to a lot of amps, Audison thesis, mcintosh, why would I want to even get an amp from them, when these guys are so much smaller and a whole lot easier to wire since they don't use huge cables like 0 gauge. The amps not in my car its in my friends audi. I'm just trying to see if there is a downside at all compared to say my 2,Polk PA660's or my PA1200.1 in comparison. Cause Richard has this big blue four channel amp and he claims it can power my whole car no problem, and based on the 2.2's performance in the audi and in his truck I'm kinda inclined to believe it. Which makes me wonder considering I have 3 amps going into my system, kinda just wondering if my choice was sound or not lol. I have been doing installs for years, but I wasn't really even born when Linear power started out so it's kinda hard to dig up info on a product from so long ago. Granted I got all three of my amps for 470 brand new.


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## Chaos (Oct 27, 2005)

It's all relative. 

In the end, Ohm's Law doesn't change.

There is a finite amount of power (current, for the purposes of this discussion) available within a certain voltage range (12.5~14 vDC) in every vehicle.

How the power supply of your audio amplifiers cope with this condition depends on the design topology.


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## ChrisB (Jul 3, 2008)

Deathjunior said:


> Why do I feel like no one who has posted a reply knows who linear power is? I don't blame you at all since they are just now restarting production of thier product


Oh, I know Linear Power quite well as I am the resident forum Linear power basher! 

Here is the listing of LP amplifiers that I owned:

2 - 5002
1 - 1752
1 - 2.2 HV
1 - LP150
1 - DPS 500

The above were not worth a flip on subwoofers at either 4 or 8 ohms mono with my "musical" tastes. Believe me, I tried to give them a fair shake in TWO vehicles that both had high output alternators and advanced technology AGM batteries. No dice!

**********************************************************

5 - 1502IQ
2 - 652
1 - DPSQ50

The above were decent on mids and highs, but every now and again I could tell when the 1502IQs ran out of steam. At least they didn't shut down completely like the others did on my subs.
**********************************************************


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## Deathjunior (Aug 2, 2011)

ChrisB said:


> Oh, I know Linear Power quite well as I am the resident forum Linear power basher!
> 
> Here is the listing of LP amplifiers that I owned:
> 
> ...



This right here is exactly what I was wondering, do they have any issues and what are they. I want to hear examples on both sides what they can and can't do. Cause like I said I wasn't really around for linear. I was born into the overseas chinese built era lol. I think my amps will be enough I just kinda wish I didn't have so many as I'm basically coating my floor with amplifier.... But damn will it look good lol. 
What do you mean ran out of steam, did they just have issues with low notes or something? Or can they not handle the load when it comes to subwoofers that aren't paper cone style like the Blues IB10 kit?


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## TrickyRicky (Apr 5, 2009)

Chris didnt like the 1502IQ because he stated it had some weird noise, but when he sold it to me I didnt notice anything. It depends on what amplifier you plan on using for the Iso-Kit. Because those IsoKits from Blues handle only about 400-600watts total and am pretty sure they dont need more than that and can go down to 200watts and still sound good. So it depends what amp your using or plan on using for the IsoKit. Just remember that certain LP's were made for woofers such as the dps500, 5002, 8002SW, 4.1HV the rest can be for mids and tweeters.

The last generation were the DPS and HV line before those was the IQ line, and before that it was the non-IQ line and so on and so on. 

Are they good, well they are A/B which are mostly for SQ not for SPL. Everyone knows that they are only upto 60% efficient while other like D are higher in efficiency. Class GH being the most efficient of them all and sound has been compared to A/B topology.

What you need to understand is that most A/B will create double power and have of it will be dissapeated in heat. So those 5002 are really making 1200watts but half of it is heat. But they use some of the best output transistors and components and are very reliable aslong as you use them properly (with the taps in the right setting).


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## Viggen (May 2, 2011)

nick650 said:


> What the hell are you talking about?


I don't know... I am not into all the technical stuff. However local home audio shop states I need a high current amp for my old Infinity kappa speakers, which my present Parasound HCA-1500's aren't (compared to Bryston). They claim a good 100w high current amp from Bryston will drive my Kappa's better then my 205w Parasound amps. They also state class D stuff (been considering a wyred4sound amp) also isn't high current. I have no clue why.... I am a funeral director & not a engineer 


Ahhhh, linear power. Every time I read that name I think of bubble gum. Anyone remember those adds??


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## SQ_MGB (Apr 24, 2008)

Deathjunior said:


> Why do I feel like no one who has posted a reply knows who linear power is? I don't blame you at all since they are just now restarting production of thier product
> 
> However, no none of what you have stated is at all what I meant.
> Accept tricky ricky who explained the situation well.
> I know the difference between pulse width modulated, and what a rail is and all the other things you guys seemed to ask. Maby this question is to out dated for most of those in today's world of amps. Anywho what the older model Linear Power HV amps had was a higher volt rail system they were a hand built amp that by converting the voltage of the inputs could produce massive amounts of power. They were rated at .0001 THD at very small voltages say 45 and 15. We have a 2 channel running in an Audi TT right now on 10 gauge wire pushing close to 200 rms per channel says our meter, and the output voltage is running around a 26. This is what i meant by high voltage. The amp is owned by and was installed by Richard of team linear power Region 6, 2010 world sq world champion. The bigger blue Linear power amps he has can run a vacuum cleaner... apparently its actually been tested.


The big blue amp I have is a 3.2HV and it's a two channel, not a four channel. We did not install that amp into the TT, we only installed the 2.2HV and it performed well.

Also, to clarify, I was NOT a world champion in any class, I was only Region 6 and National SQ POINTS champion in 2010.

As was stated before, there is a thread on here debating high current vs high voltage that has a lot of good info in it.

I believe my 2.2HV makes somewhere around 175-185 watts per channel, but I don't recall testing it in the TT? We only swapped it in to compare it against his RE amp and we were only using the left channel at first, not mono. When we used the amp in bridged mode, the little subs were NOT happy. I'm not sure where the voltage numbers you mentioned are coming from?

As far as running out of steam goes, I've used Linear Power since 1987 and the closest thing I've ever experienced to "running out of steam" was in my MGB when I used a pair of DPS200's to handle amp duties. To get the volume I wanted (ie, have the top down and drown out wind noise) I had to have the volume up to 32-34 out of 35 on the headunit. When I swapped to DPS350's, I could get the same volume at 25-28. Maybe it was the difference in gain settings, maybe the difference was power, don't know, don't care. I just know it got louder and that's what I was after. Never once did the amps (200's or 350's) sound "strained." I just got tired of having to turn the volume knob wide open to listen to the radio.

Hope that clarifies things somewhat on the different cars.


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## TrickyRicky (Apr 5, 2009)

Is that you Richard (SQ_MGB)? Welcome to the world of DIYMA. Dont let this guys talk you out of here, they tend to bash on LP a lot, but am still here.

I was also confused where he was talking about 45v and 15v. Because thats not from the speaker plugs, unless he is reading his multimeter wrong. I mention the rail voltage is pretty high on Linear Power amps, because I myself have measured the 5002IQ at 110v. I havent measure other brands but I wouldnt be surprise to see the same voltage on a 2000watt amplifier from a different brand when LP has the same voltage on a 500watt amp. Talk about reliability and headroom.


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## ChrisB (Jul 3, 2008)

TrickyRicky said:


> I mention the rail voltage is pretty high on Linear Power amps, because I myself have measured the 5002IQ at 110v.


I thought the rail voltage was higher on them due to the fact that they were originally designed to work at higher impedance loads? I remember a time in the history of car audio when 8 ohm, single voice coil subwoofers were actually common items. I also remember a time when most ran cassette decks that could not reproduce much content below 50 Hz. I can say that I don't recall any component or coaxial sets marketed for car audio that were 8 ohms though. While there may have been some, I don't remember seeing any.


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## TrickyRicky (Apr 5, 2009)

ChrisB said:


> *I thought the rail voltage was higher on them due to the fact that they were originally designed to work at higher impedance loads?* I remember a time in the history of car audio when 8 ohm, single voice coil subwoofers were actually common items. I also remember a time when most ran cassette decks that could not reproduce much content below 50 Hz. I can say that I don't recall any component or coaxial sets marketed for car audio that were 8 ohms though. While there may have been some, I don't remember seeing any.


Its higher with the taps set at 4 (which is 110v) at 2 the rail is about 85-90v. This goes for any LP that has the tap's. As for the speakers, there is a reason why some are 8-ohms I've read on another thread how 8-ohm speakers have higher sensitivity (most over 92dbs) so no need for lots of power. But the speakres that are under 4-ohms are as bad as 81db in sensitivity so you would need more power (remember double power only gains a 3db). I wouldn't be surprise if they come out with 1-ohm componenets pretty soon or even dual 1-ohm voice coil coaxils just to get more power out of the amps.


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## ChrisB (Jul 3, 2008)

TrickyRicky said:


> As for the speakers, there is a reason why some are 8-ohms I've read on another thread how 8-ohm speakers have higher sensitivity (most over 92dbs) so no need for lots of power.


Ahh, true... Also, remember subs back in the day required HUGE enclosures and didn't take as much power to get loud. Then again, I can't really say that I miss building a 3 cubic foot ported enclosure for a single 10" subwoofer. While in college, my now attorney had a single 12" Savard in a bandpass box. That enclosure was 12 cubic feet in size and took up the WHOLE trunk of his car!


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## SQ_MGB (Apr 24, 2008)

TrickyRicky said:


> Is that you Richard (SQ_MGB)? Welcome to the world of DIYMA. Dont let this guys talk you out of here, they tend to bash on LP a lot, but am still here.
> 
> I was also confused where he was talking about 45v and 15v. Because thats not from the speaker plugs, unless he is reading his multimeter wrong. I mention the rail voltage is pretty high on Linear Power amps, because I myself have measured the 5002IQ at 110v. I havent measure other brands but I wouldnt be surprise to see the same voltage on a 2000watt amplifier from a different brand when LP has the same voltage on a 500watt amp. Talk about reliability and headroom.





ChrisB said:


> Ahh, true... Also, remember subs back in the day required HUGE enclosures and didn't take as much power to get loud. Then again, I can't really say that I miss building a 3 cubic foot ported enclosure for a single 10" subwoofer. While in college, my now attorney had a single 12" Savard in a bandpass box. That enclosure was 12 cubic feet in size and took up the WHOLE trunk of his car!


Hi Ricky, yes it's me. Thanks for the welcome. I'm not sure where he's getting his voltage numbers because we never put a meter on the amps (any of them) when we were changing them back and forth to see the difference. The battery voltage seems to hover around 13.4-13.6 until he really beats down on it and then it drops to around 12.8. I have no idea what the output voltage is, so I'm not sure where the 45 and 15 numbers are coming from.

I do know the four Elemental 7kv's we HAD in the car didn't like the 2.2HV bridged at all. They were fine when I ran them off one channel at 4 ohms, but 4 ohm bridged knocked one dustcap off and loosened another one. They were a lot more "punchy" when we had the 2.2HV on them, if that's the right word. They just had a different sound when he went to the class d amp, it just didn't sound as tight. The owner of the TT is using a pair of 10's now and likes it better.

ChrisB, that brings back some memories! I haven't heard the name Savard in a loooong time! I also can't say I miss building a 2-2.5 cu.ft. box for a single 12" sealed, and even larger ported. Thanks for the trip down memory lane!


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## Deathjunior (Aug 2, 2011)

Yea richard, I'm trying to do a little bit of research on the amps, mostly cause to me there one of the best sounding amps i have probably heard for such a small size. Even just the one in the audi on the MB quartz sounds really good. So I'm kinda worried I could have made a better choice when it came down to choosing my amps. For the voltage calculations I basically went off of the numbers that the owner had said and did the math from there though his numbers were more than likely a guess it made sense considering that were more than maxing out the MB quartz power capabilities and it kinda confuses me how it creates so much clean power. So I came on here hopefully to learn a few of the differences between the linear powers and regular class A/B both pro's cons lol. Little did I know I would find only a few who knew the product and stir up a bit of old memories.


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## AKheathen (Sep 10, 2011)

mk, i got kinda lazy, since the discussion seemed to have side-tracked to a linear power discussion when i skimmed, so i'll respond to the o.p. direct. you really need to compare the specific amps in question directly. the more rails sag, the lower sq, imho, with exception. now, if you are looking at a cheater amp, well, you drag it way down to the bottom, then you are likely not going to see much in the way of decent sound, though the power will be nice, on the other hand, you run an amp at higher impedance than minimum, you are not going to get much sag, and it can function a bit more effectively. take for instance a zr amp. typically, you can get the same power at 2.66 as you will see at 2ohms, though it may sound allot better at 3-4ohms, since it's not being drug way down. the 2.66 cap on power gain illustrates where rail sag is really starting to drop in efficiency and effect, now you turn around and look at it's predecessor (zr1000->xs100, i.e.) and the initial rail voltage is pretty low, and set, so you need to drag it down to get decent output, but better sound can be had just before minimum+.... i guess what i'm saying, is pick what meets your needs, and then pick the amp that you can set up near highest efficiency and less strain, and my experience has always seen better sound as a result


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