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why are tube amps sporting such low RMS numbers?

30hz MAGIC, thank you for responding to my post.

If the amplifier is connected to a dedicated 20 ampere circuit with a line voltage of 125 volts, that equates in a perfect world to 2500 watts. Of course the world is not perfect and the available power will be less.

The first picture is taken from the Parts Express web page. The second picture is taken form the owners manual for this amplifier. It is interesting that the advertising copy gives a rating into a 2 Ohm load and the instruction manual does not.


It appears that the Pyle amplifier meets you current needs and you are happy with the way it sounds and it has been reliable up to this point. A quick look on the internet returns some rather favorable reviews.

And it appears that your tastes in sound reproduction may differ from what might be considered by some on AK as nominal. That is your choice. And it is your choice to risk hearing damage, a fairly high risk if you listen at the levels that you have indicated (130 dB SPL, even 120 dB SPL can result in almost instantaneous hearing damage). To keep this somewhat simple I have left out any discussion of weighting as applied to SPL measurement.



If the amplifier is connected to a dedicated 20 ampere circuit with a line voltage of 125 volts, that equates in a perfect world to 2500 watts. Of course the world is not perfect.

I did try to find information relating to the measured real world performance of this amplifier and all I found was information similar to what is posted on the Parts Express web page and the owners manual.

So no information supporting the claim of 8000 watts peak. And by the way, to be technically correct there is no such thing as peak watts or RMS watts. A watt is a watt. It is a unit of work equal to one joule per second.

The term RMS (Root Mean Square) is applied to the voltage and or current.
The term has come into common usage to signify power that is calculated using the RMS values for voltage and current.



"Sundown SA-15 can do 150 on burp, 1000watts, my friend."

It is my understanding, that in general when measuring SPL "on burp", it is done, at a single frequency and if possible at the resonant frequency of the cabin and for a short duration, just a few seconds.

This is a horse of a different color and in general does not have a correlation in home audio.

I can take 4 APC-30 speakers and less than 150 watts and produce a peak SPL of over 130 dB at 1 meter from the speakers. Again, this has no correlation in home audio.

I took a quick look at the specifications for the speaker that you mentioned, see the third picture. it appears from the manufacturer’s web page, the sensitivity is about 87 dB per watt at 1 meter, so 1000 watts, which is an increase of 30 dB, would produce a maximum SPL of about 117 dB less any power compression.

Any increase in SPL above this figure would have to come from the resonant frequency of the speaker enclosure, the resonant frequency of the cabin and the fact the acoustic energy is being contained in the small volume of the cabin.



I am interested in the particular configuration that was used to obtain an SPL of 150 dB with an audio power of 1000 watts using the speaker that you mentioned.


Are these specifications inaccurate?


Again, this has no correlation in home audio.


Getting back to your original question. You like what you like and by you own admission:

"Our audio dreams are such difference between each others. Your chasing reality, precision, accuracy. I'm chasing artificial, imagination, a lie.

I want my experience to be over the top and unrealistic.
Colors to some are only colors until there's too many of them, only then are they beautiful.
To others they are a nightmare, but not to me",

You do not have the same interests in audio as some on AK.

There have been some very good explanations as to why some here prefer tube type amplifiers and some good explanations of the SPL that can be achieved. In this context, extremely high SPL is not necessarily the driving factor.

There are other issues such as the the order (not amplitude) of the harmonic distortion that is produced by tube amplifiers.
 
SuperjazzyJa said:
The watts/dB with regard to speaker sensitivity assessment is pretty good. However, the power handling spec is meaningless. The speakers in my secondary system are only rated to handle 25 watts each. I once had the opportunity to prove this to a neighbor. My wife and sons were out. I subjected the speakers to approximately 50 watts each for over an hour. No harm done. I did this because he insisted that my 60 wpc Onkyo receiver was going to blow them. Clipping is what blows speakers, NOT more watts than the speakers are rated for. The only reasons I can think of for manufacturers to even give such specs are to cover their butts in case someone blows a speaker and a lot of consumers want such a rating. The first reason is so that if someone blows a speaker by driving a 100 watt amp into clipping powering a speaker rated @ 25 watts and blows it, the warranty is void. The second is because most people believe those specs to be true.
Click to expand...

This thread has now officially jumped the shark.
 
It has...

I tried to steer it back with my closing comments in my previous post, but it is where it is.

"Clipping is what blows speakers, NOT more watts than the speakers are rated for."

Not exactly. Speakers are damaged when supplied with more power than they can handle, regardless of the manufactures specifications.



Speaker do not care about the shape of the waveform.

A number of complex and related things happen when an amplifier is driven into clipping.

Clipping may cause an increase in the overall effective power output of an amplifier, and that increase in power may result in a power level that is greater than the speaker can handle.

But if the exact same effective power is supplied to the speaker as an unclipped single, the result would be the same.

The key is effective power. That is the DC equivalent power in joules per second. Speakers basically have three power related failure modes, overheating of the motor assembly including the voice coil and former and over extension and excessive physical forces, which can result in several types of mechanical failures.

These failures are caused by excessive power, not the shape of the waveform.

One can feed direct current to a speaker driver and as long as the thermal capability and or the physical force capability is not exceeded, no damage will be done. It is all about power. The power the driver can actually handle, not necessarily the manufacturer's power handling rating.

To be clear, some amplifiers do not behave well when driven into clipping.

But per one of the OP's posts and somewhat back on track, and somewhat back to what the OP is discussing, I am still interested in the configuration of the speaker that the OP mentioned that resulted in an SPL of 150 dB when being driving with 1000 watts.
 
I hate to see somebody jumped on for their choice of amp. Does it matter who made it or what the rating is, or whether it will actually perform at it's rated output if the OP is happy with it? One of the common ties that bind at AK is the search for budget gear, and it seems like the OP has found something that works for him. It's not at all uncommon for fairly expensive HT set ups to run "budget" PA amps on the subs. That's all the OP is doing, just on a lower budget.

As long as he stays in Illinois, I say more power to him! :thmbsp:

As for the whole tubes vs SS for dedicated sub duties, I think we can all put that one to bed.
 
Jeffery, I agree as I indicated in a previous post.

I cautioned him about listening at elevated SPL, but acknowledged his different preferences.

If he is happy with his return on investment, then that is all that is required.
 
JBL GUY said:
It has...

I tried to steer it back with my closing comments in my previous post, but it is where it is.

"Clipping is what blows speakers, NOT more watts than the speakers are rated for."

Not exactly. Speakers are damaged when supplied with more power than they can handle, regardless of the manufactures specifications.



Speaker do not care about the shape of the waveform.

A number of complex and related things happen when an amplifier is driven into clipping.

Clipping may cause an increase in the overall effective power output of an amplifier, and that increase in power may result in a power level that is greater than the speaker can handle.

But if the exact same effective power is supplied to the speaker as an unclipped single, the result would be the same.

The key is effective power. That is the DC equivalent power in joules per second. Speakers basically have three power related failure modes, overheating of the motor assembly including the voice coil and former and over extension and excessive physical forces, which can result in several types of mechanical failures.

These failures are caused by excessive power, not the shape of the waveform.

One can feed direct current to a speaker driver and as long as the thermal capability and or the physical force capability is not exceeded, no damage will be done. It is all about power. The power the driver can actually handle, not necessarily the manufacturer's power handling rating.

To be clear, some amplifiers do not behave well when driven into clipping.

But per one of the OP's posts and somewhat back on track, and somewhat back to what the OP is discussing, I am still interested in the configuration of the speaker that the OP mentioned that resulted in an SPL of 150 dB when being driving with 1000 watts.
Click to expand...

http://m.youtube.com/watch?v=nMN5qavR9r4

Seems I was wrong about the SA-15 doing near 150db. Granted, that was a prototype video I saw 5 years ago. Memories just bad, sorry. I mean.... Still though, 142db with 1000watts.
I have near 4500watts.
 
I don't think anybody is jumping on the OP.

If you're going to come on an audio forum that is made up of many well seasoned and experienced members and toss around numbers like 8000 watts, and 140 db, and then want to support it by parroting the claimed specs on the shiny box of your PYLE amplifier, you should probably expect some doubtful and scrutinizing posts.

To add insult to injury, the OP seems to want to ignore many posts intended to be helpful and informative to him.
 
House de Kris said:
I'm not kcbluesman, but I'm guessing it is this statement you made:

"Clipping is what blows speakers, NOT more watts than the speakers are rated for."
Click to expand...

The statement is true and I stand by it 100%. If telling the truth is jumping the shark, I weep for the future. If I had time to tell of every time that I have tested this statement or witnessed other people testing it, the post would be the equivalent of a 2000 page book! I have seen speakers only rated to handle fractions of the power they were given survive just fine. I have also seen drivers, usually tweeters give up the ghost after only a few seconds of clipping when powered by amps that could not develop much more than a quarter of what the speakers were rated for.

Most specs given in the owner's manual of audio gear and posted on the backs of speakers have no real meaning. Frequency range of any piece of gear and the weight of an amp in relation to it's rated output are among the very few meaningful specs that a manufacturer will provide.
 
SuperjazzyJa said:
The statement is true and I stand by it 100%. If telling the truth is jumping the shark, I weep for the future. If I had time to tell of every time that I have tested this statement or witnessed other people testing it, the post would be the equivalent of a 2000 page book! I have seen speakers only rated to handle fractions of the power they were given survive just fine. I have also seen drivers, usually tweeters give up the ghost after only a few seconds of clipping when powered by amps that could not develop much more than a quarter of what the speakers were rated for.

Most specs given in the owner's manual of audio gear and posted on the backs of speakers have no real meaning. Frequency range of any piece of gear and the weight of an amp in relation to it's rated output are among the very few meaningful specs that a manufacturer will provide.
Click to expand...

If the truth is important to you, why spread such misinformation? Take the time to actually understand the the variables involved with clipping rather than just repeating the old under-powered amp myth.

Yes, a clipping amp can blow tweeters. But it is not the clipping that causes the problem...it is that the power going to them exceeds their capabilities (regardless of their rating). If the amp were not clipping, but putting out the same power, the tweeters would be equally damaged.

And yes, sometimes people continue to turn up the volume on a clipping amp....which increases the output at the higher frequencies to a point beyond what the tweeters can handle. Again, it is the power, not the clipping, that does the damage.

A 2000 page book? Let's assume one story of damaged speakers per page....you are seriously telling us that you have personally tested or witnessed a speaker being damaged by clipping 2000 times? Come on, dude...you are flying WAY over the shark with this kind of claim. And in any case, how would you know that it was clipping that did the damage? What is it about clipping that does the damage? Can you explain it, please?
 
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kcbluesman said:
What is it about clipping that does the damage? Can you explain it, please?
Click to expand...

I'd be interested in learning this too, from someone who knows the truth. But, please, not in this thread. Start a new one to share your experiences. I'm sure you'll get many replies and a very lengthy thread.

To take this thread back on topic, the question raised was, "Why are tube amps sporting such low RMS numbers?" Because it is diffucult (I didn't say impossible, just difficult) to produce tube amps sporting high RMS numbers that the buying public could afford.
 
bowtie427ss said:
I don't think anybody is jumping on the OP.

If you're going to come on an audio forum that is made up of many well seasoned and experienced members and toss around numbers like 8000 watts, and 140 db, and then want to support it by parroting the claimed specs on the shiny box of your PYLE amplifier, you should probably expect some doubtful and scrutinizing posts.

To add insult to injury, the OP seems to want to ignore many posts intended to be helpful and informative to him.
Click to expand...

Just common sense that 4500RMS will reach 140db's....
Plus, never tossed around 8000watts. If you were paying attention you would have noticed I said I KNEW it wasn't an 8000watt amplifier. Where were you on that one?

I'm not ignoring those posts either, iI'm just reading them and taking in the info I can. I don't need to reply to listen, apparently you don't understand that. I will be honest, some of it I don't even understand. But YOU however, make an idiotic claim that I'm ignoring them?!?

Gtfo...
 
House de Kris said:
I'd be interested in learning this too, from someone who knows the truth. But, please, not in this thread. Start a new one to share your experiences. I'm sure you'll get many replies and a very lengthy thread.

To take this thread back on topic, the question raised was, "Why are tube amps sporting such low RMS numbers?" Because it is diffucult (I didn't say impossible, just difficult) to produce tube amps sporting high RMS numbers that the buying public could afford.
Click to expand...

I'm waiting for this thread. Funny I hear so much about distortion but what exactly happens to the woofer?
 
kcbluesman said:
.....
What is it about clipping that does the damage? Can you explain it, please?
Click to expand...

When an amplifier (mainly solid state) is driven into clipping, the squared top and bottom of the waveform add harmonics, or a LOT of high frequency content. In most speaker systems, the woofers handle most of the power, and the tweeters are rated for much lower power. The power produced by these artificially generated harmonics is what burns out the tweeters. Tube amplifiers driven into clipping don't quite "flat top" the signal, so the higher harmonics generated have less power than with a solid state amp. Note that this applies to harmonic distortion generated within the amplifier. It shoud always amplify and pass all harmonics that are in the original signal.

As for speaker power ratings, there are often assumptions that the speaker will be reproducing "normal" music, where the peak to average ratio comes into play. Acoustic Research published a full set of numbers for the AR-3A.....

11 watts rms at any frequency for an indefinite period of time
23 watts for at least 11 seconds
overloads of 400 watts for 2 seconds.

The assumption is that the average listening level will be around 10 watts or so and a 400 watt musical peak would be 16 dB over that average. Unlike IHF, dynamic headroom, and other inflated (bogus) amplifier ratings, 2 seconds is actually long enough to handle some musical transients.

Speaker manufacturers will also often specify power in terms of the amplifier to be used. In the above example, if AR wanted to publish "good" numbers just to play that game, they could simply have said that the speaker is suitable for use with a 400 watt amplifier and one would assume that they are 400 watt speakers.
 
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