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Jim Coash

The truth about amps, power and efficiency

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Greetings:  I am enjoying being part of the Carver website.  There are so many things to read and nearly all of them bring back memories of my experiences with audio, sound re-enforcement and customers.  It is abundantly clear to me that, in some ways, things haven't changed much.  The confusion about the relationship between power, volume and speaker efficiency is still one of the least understood concepts.  Of all the topics I dealt with during my years the number one question(s) had to do with power. Bob Carver helped me to answer those questions more than anyone else but like me he had difficulty getting people to listen to the truth.  Often I lost a potential sale simply because I chose to answer a question honestly only to have someone call me stupid or arrogant and walk out of my store.  My wife told me for years that if I would simply have played the game the same way the appliance store sound jockeys did that we would have been much better off financially.  I'm sure she was correct but my Dad brought me up to be brutally honest and often that worked against me on the sales floor.  I have just been reading some of the posts in the amp section of the website and gritting my teeth.  So, be warned, if you can't handle the truth, just back away slowly and continue to live in the world of specifications and illusion.  Now, where do I start?
 
First.  A common question asked of me when someone first walked into my store was also the most dangerous for me. Someone  would be standing in front of a system we had set up and after a polite passage of time I (or one of my people) would walk up casually and ask how I might be able to help.  No one trusted salesmen, then or now, and with ample reason. My advice today is still the same as it has been all of my life; the chance that you will actually run into a salesperson who is A) honest, B) knowledgeable or C) actually interested and capable of helping you are slim to none.  That is what made me and a few other true A/V professionals stand out from the crowd.  I knew what the answer to my opening question would be because it was nearly always the same.  "No thanks, I'm just looking".  If I said OK and walked away, I had no chance. Instead I would ignore the answer and take a cue from their body language.  There were plenty of variations.  Usually I would say something like this.  "I couldn't help but notice that you seem interested in that Carver amplifier and I just happen to have a CD with me that I can play for you" and I would just open the drawer, drop it in, set the volume level, press play and walk a few steps away.  When the music started and it sounded so good I would then suggest that if they wanted to adjust the volume or select another track that they should feel free.  When they did, we had a rapport established.  If they seemed less than interested in the music I would ask if there was something else prefer that I play or if they might have brought a favorite disc in with them.  Of course, in the early years I was using vinyl.  When you notice that the customer is showing interest the next step is to elicit some questions from them.  Once they began speaking you had an opportunity.  Keep in mind that I did not work in a mall at an appliance store.  If they were there it was because they pulled into the lot and walked into the store that clearly said "Stereo Showcase" on the sign.  That was a big clue in and of itself.  Most of my customers were male but not all and making women feel comfortable was extremely important because much of the time they would be a large part of the decision. If there was a child or children with them I would bring a toy with me and ask her if it was OK to let them play so that we could talk.  That was a big ice breaker and often she would give me a grateful smile, unfold her arms and join the conversation.  Women are very good customers but often they are more concerned with they way the equipment looks, how easy it is to operate and, of course, the cost.  I felt that every component and every system be clearly labeled with with make, model number and price.  In each system I would show what was included with the package, what the warranty coverage was, what the system discount was and that we would be glad to deliver the equipment and install it.
 
The cool thing was that by the time this had happened we were friends.  Usually this was their first experience with this treatment and there was no threat or pressure at all.  Now I just had to negotiate the minefield of questions.  While this was happening I would be busy.  I might move the speakers away from the wall and a little further apart or cue up another selection on a different source so that they could see how easy it was to play a tape of choose a radio station.  Often that would make someone say something like "Does it sound better if the speakers are like that"?  I needed to be careful.  The easy answer was yes but it might be that they were concerned about having enough room or needing "special" placement for it to work.  The best answer was something like "These speakers will sound good almost anywhere you put them but if you have a favorite chair you might like to arrange them for the best sound from that spot".  In later years as more people began shopping for integrated A/V systems we had a TV set up between the speakers and then you could quickly start the VCR or video disc player, cue up a dramatic scene with great audio and move a chair or two to a place where the picture and sound would be superior.  All you had to do was gesture to them when they noticed what you were doing.
 
After a good demo you could nearly always tell if they were impressed and interested.  Sometimes I would see a "spec" sheet or business card in hand from Highland, Fretter or ABC Warehouse.  Naturally I knew what they had, what was on "sale" and what they had been told by the folks over there.  Sometimes the next thing said was that they had seen the big sale and that was what had sparked their interest.  Once again, be careful.  Depending on the people involved I might say something like "Oh, you mean the huge once in a lifetime sale that only runs until midnight and if you don;t get back soon, they will all be gone"!  That might be too strong for some.  A better approach was often to say "Does this system sound as good as the one you heard earlier"?  I rarely lost on that one but sometimes I would get "No, but their speaker were 4-way and the amp had twice as many watts".  Now we were really down to brass tacks.  I would carefully suggest that if my package was comparable in price why were the number or size of speakers in the box relevant and if my system clearly had enough power to fill their room with music why would having more power, at least on the spec sheet important?
 
Once they understood that I would not lie to them and that I had an answer for each of their questions that I could explain to them in terms they could understand,  I had a big advantage.  Now was the time for the absolute truth.  First, there is no specification that is more important than what the system actually sounds like and that appliance stores thrive on using specifications to distort the truth.  In some cases I actually had people tell me that they hadn't actually heard the system over there because it wasn't hooked up.  Not only were all of mine ready to play but if they said that the speakers were too big or too small of the wrong color I would instantly change that while they stood there.  At times all I needed to do was press the "B" speaker switch but even if I had to step into another room while they listened to bring in a pair of speakers that they did like it was no problem whatsoever.  I would also move people to a different system or completely build a system custom to their requests while they watched.  People love that kind of thing and it re-enforced my knowledge, how easy it was to hook things up and my willingness to find exactly what they wanted in terms of features, size, performance and price.  Anyone who worked in my store was required to do this and they had to do it as though it was second nature and while they continued to answer questions.  If someone said "Can I get this Carver system with those KEF speakers"? the answer was of course and by the time they said it I was already moving whatever needed to be moved to make it happen.
 
Inevitably the question would come.  "How many watts are those speakers"?  This is the single most dangerous and difficult question to answer and where lost sales usually come from.  If you make a statement that your client feels sure is a lie, you are toast and yet the only honest answer, the truth, is the wattage ratings on speakers are essentially meaningless.  So many times this brings a look of skepticism that average salespeople cannot overcome.  The real problem is to keep their confidence long enough to prove the point.  They have already heard all of the other salespeople and their friends talk about, brag about how many watts their speakers have/are.  Speakers do not have watts; amplifiers do.  Any well designed speaker can handle the full output of even the largest amplifiers provided they are not driven into distortion.  One of my favorite things to say was "How many horsepower are the tires on your car"?  I would get this weird look as though I was an idiot.  Your tires do not have horse power.  Your engine does.  Speakers do not have watts.  Your amplifier does.  How could I prove this?
 
My favorite was was to step up to the system that had the Carver 1.5 amp in the system, show them the "spec" sheet, point out the rated power, disconnect the large speakers from the system and place a pair of small bookshelf speakers on top of the big speakers and crank it up.  Really loud.  For this to work you must have the preamp set at neutral (no tone controls of loudness button) and it is a good idea to have the infrasonic filter on.  You can then point out that you have a 600/WRMS per channel amp driving a tiny speaker, perhaps a Boston Acoustics A-40 or a Paradigm Atom which have spec sheets that say "amplifier power recommended 25-100 watts" and that the LEDs on the Carver are clearly approaching the top.  Yet, there is no distortion, no distress and other than the lack of deep bass, the speakers sound wonderful.  They will play like that for an hour before the crossover gets warm.  The same demonstration was done each weekend I had a wedding reception to play. I used the largest amplifiers available, Carver 1.5 Pros, often run mono for double the wattage driving one pair of E/V SX-200 speakers all night long at very high SPLs without any problem whatsoever.  For 35 years I played hundreds of gigs like that with dozens of different amps and speakers.  During those years I NEVER damaged a single driver in any speaker!  Why?  I never allowed the amps to clip, never used any EQ or even tone adjustment and always used the low cut on the equipment to eliminate infrasonic information.  I was also using the active crossover that was part of the E/V system and the matching SBa-200 subs (one or two) with the crossover set at the factory at about 100 hz.
 
That is the absolute truth.  There is plenty more to say on the subject but I want to let that sink in and allow your comments.  
By the way, if you doubt me on this, ask Bob.  You can also look up the E/V Sound Bible on line or the JBL white paper on speakers and power.  They will back me up.  I did lose a few customers this way but I locked in a whole lot more.  Jim
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Jim...first welcome to the forum and second that was a very interesting read. Thanks for the insite. If I'm reading this correctly, you are saying you can run more than double the watts of amplifier power into speakers rated less for siginificant periods of time without damage to the voicecoils as long as no distortion is present. This is my simplistic view of your post.

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One of my favorite things to say was "How many horsepower are the tires on your car"?  I would get this weird look as though I was an idiot.  Your tires do not have horse power.  Your engine does.  Speakers do not have watts.  Your amplifier does.
 
I love this metaphor!
 
Jim, thanks so much for taking the time to write about your experiences. It should be required reading for any salesperson in *any* business, it's the principles that matter. Over the decades I've run into only three or four good, competent, knowledgeable audio gear salespeople. And I've suffered through hundreds of indifferent clowns who just needed to get out of my way. Guess who got my repeat business? emwink.gif
 
Once again, glad to have you with us! 

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"No thanks, I'm just looking". If I said OK and walked away, I had no chance. Jim

 

That's probably a true statement for most people. But I'm not my wife so I'm not in a store just "looking". I'm there to either do my own research on a product or make a purchase. So a sales staff has a 50/50 chance with me. If I'm doing research, I won't really need assistance unless and I have a question or two and then I will engage them. Otherwise I only need their help to actually buy the item.

 

While it's unfortunate, today my experience has been that most sales people do not know the products they are selling and as such the generalization is to dismiss ALL sales folk their usefulness.

 

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Welcome aboard Jim! And thanks for the great Saturday Morning Read!
 
As I remember, in the '70s there were specification standards for amps that read "xxx watts/channel, both channel driven, 20 - 20k Hz  with less than 0.xx % THD.
Those standards seem to have disappeared.
 
About 25 years ago I bought a carver C-1, m-1.0t and Klipsch KG-4 speakers. I knew then that clean bass requires power in reserve and that clipping is a speakers worst enemy.
While the Klipsch's are rated at 100 watts @ 6 ohms, and the 1.0t is rated at 200 watts/ch @ 8 ohms, it would seem the amp would be able to destroy the Klipsch's. 
Never happened. 
Even under heavy Tequila influence rocking to Montrose! party.gif
 
More power is always the answer!!
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Jim...first welcome to the forum and second that was a very interesting read. Thanks for the insite. If I'm reading this correctly, you are saying you can run more than double the watts of amplifier power into speakers rated less for siginificant periods of time without damage to the voicecoils as long as no distortion is present. This is my simplistic view of your post.

 

I'm in a quandary too, I think he's saying that a driver rated for 100w can take an infinite amount of wattage input as long as it's not distorted or the volume doesn't exceed the drivers limits.  But once the driver starts receiving in excess of it's rated power input it will  start distorting there fore thats it's limit has been met and the volume must be reduced.  It's not the silent watt that hurts, it's the modulation, sound, etc. delivered at higher volumes.  The m 1.0T MKII is rated lets sayat 550W output.  When turned on it's silent even though the output is 225W RMS.  The drivers are not responding to the wattage because there is no sound.  Once sound is delivered the drivers respond, and their limitations can't be exceeded or damage will be done.  I believe thats his point.  Lets see.

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I only realized this truth a few years ago. It took a bit for it to sink in! Along the same lines, it's important to understand that having too little power is much more dangerous than having plenty.. Clipping destroys speakers!! Great read.. thanks!

Chris

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Many of the sales people I've come across are clueless but I've been lucky enough to have met a few good ones.
Here's a story about one of my earliest experiences with retail sales and personal audio gear.
 
I was already pretty knowledgeable about audio when I went shopping for my 1st component stereo system.
(I'd been in theater since the age of 7 and done technical sound (reinforcement/recording) since my early teens.
It was the early 70's, I was in my early 20's, and I was stationed at Camp Mercury, NV (Nevada Test Site).
There was no base exhange or retail stores so shopping for anything required a 65 mile trip into Las Vegas.
 
I spent several weekends going from store to store looking at what was available versus what I could afford.
Upon arrival at each store I'd thank the "greeter" and let them know I would find them when/if I had questions.
While inspecting/drooling over the gear they had on display I would listen to their banter with other customers.
Then I would either pick out one that knew the equipment, or go directly to the owner/manager for assistance.
If he was savvy (there were almost no female sales people) and I was able to develop a rapport I would proceed.
Most of the time I'd end up leaving quietly but I did find a few honest, helpful sales people that I began to trust.
 
On the 3rd weekend I went directly to what had become my favorite store (Gareheim Music) and salesman (Tony).
I picked out the components I wanted (Pioneer SA-6100 and Technics SL-1200 TT) and auditioned speakers.
(I think I wound up with a pair of Sansui's because they were on sale and I'd spent more than I'd planned on the TT.)
He helped me load my trunk and offered to buy lunch but I had a long drive back and was anxious to hit the road.
20140208094723772.jpg 
 
I went back to Tony several times before I completed my tour and moved back to Chicago in 1976.
I upgraded to a Pioneer SA-8500 and added a CT-F6161 cassette deck and a Technics ST7600 tuner.
20140208095558266.jpg 
 
I recommended Tony to all my friends and we kept in touch until he died in a car accident in 1992.
Some sales people DO make a difference. 
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Interesting. I did sales too for a while and worked the same way. I have said the same thing for years and still people don't believe it. I used a different analogy. I would say imagine you and I running around a track. I'm have your arm pulling you to keep up with me. As long as I am pulling smoothly I can even pull you faster than you may normally run but if I start running out of energy and started running in a herky jerky motion while still pulling you along by your arm what do you think will happen. Most realized their arm or shoulder joint could get damaged. I could then relate distortion caused by an amp clipping and damaging the speaker. It got a lot of laughs sometimes but I like your analogy better.
 
I always got repeat sales and new customers from referrals.  Never tried to over sell of BS them.
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About 25 years ago I bought a carver C-1, m-1.0t and Klipsch KG-4 speakers. I knew then that clean bass requires power in reserve and that clipping is a speakers worst enemy.
While the Klipsch's are rated at 100 watts @ 6 ohms, and the 1.0t is rated at 200 watts/ch @ 8 ohms, it would seem the amp would be able to destroy the Klipsch's. 
Never happened. 
Even under heavy Tequila influence rocking to Montrose! party.gif

 
This seems like a good thread to relate the *one* time (so far!) that I UN-intentionally destroyed a speaker with a Carver amp:
 
Back in college, I had a setup with my homemade speakers that I lugged in and out of the dorm. Two 15" woofers, in two cabinets, per side. Plus a cabinet each side for the mids/tweeters. 8 ohms per combo, passive crossovers and ran in parallel for 4 ohms. All driven long, loud, and often by my one TFM-45 (sourced by a high-speed portable CD player. Kids...)
 
Across the hall was a fellow audiophile. He had some nice gear, including a Carver receiver (no idea which, sorry) and a pair of Klipsch KG-4's. Sounded absolutely fantastic! BTW, we once made a trip into the city to a hifi store, where we all agreed their KG-4's sounded just so-so. We chalked it up to the tiny, cinderblock-walled dorm room working well for our speakers.
 
Anyhow, one day he wanted to try my amp in his system. No problem! We listened for a bit, accordingly, then he wanted to really crank it. Mind you, he was always bragging about how tough his KG-4's were and how indestructible they were. So he cued up some Rush, turned the volume up...
 
We heard the first note and three drum beats of "Tom Sawyer" before white smoke filled the room. It was that quick, and from both speakers! yikes.gif
 
After we opened the windows and let the smoke clear out, my buddy made a call to the Klipsch factory. He explained the situation to them, to which they replied, "A Carver amp? Yeah, that'll do it!" To Klipsch's credit they mailed him new drivers and crossovers, and he sent the old burned ones back to them(yes, all woofers were toast!). Only cost him shipping! What a great company!
 
I've used that TFM-45 for two decades after that, with all kinds of speakers, without a problem. I only just recently checked it for DC offset (fine), and there's no way for DC to propagate through it from the input. So it must have been just too much instantaneous voltage or current that caused those poor little KG-4's to combust. 
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About 25 years ago I bought a carver C-1, m-1.0t and Klipsch KG-4 speakers. I knew then that clean bass requires power in reserve and that clipping is a speakers worst enemy.
While the Klipsch's are rated at 100 watts @ 6 ohms, and the 1.0t is rated at 200 watts/ch @ 8 ohms, it would seem the amp would be able to destroy the Klipsch's. 
Never happened. 
Even under heavy Tequila influence rocking to Montrose! party.gif

 
This seems like a good thread to relate the *one* time (so far!) that I UN-intentionally destroyed a speaker with a Carver amp:
 
Back in college, I had a setup with my homemade speakers that I lugged in and out of the dorm. Two 15" woofers, in two cabinets, per side. Plus a cabinet each side for the mids/tweeters. 8 ohms per combo, passive crossovers and ran in parallel for 4 ohms. All driven long, loud, and often by my one TFM-45 (sourced by a high-speed portable CD player. Kids...)
 
Across the hall was a fellow audiophile. He had some nice gear, including a Carver receiver (no idea which, sorry) and a pair of Klipsch KG-4's. Sounded absolutely fantastic! BTW, we once made a trip into the city to a hifi store, where we all agreed their KG-4's sounded just so-so. We chalked it up to the tiny, cinderblock-walled dorm room working well for our speakers.
 
Anyhow, one day he wanted to try my amp in his system. No problem! We listened for a bit, accordingly, then he wanted to really crank it. Mind you, he was always bragging about how tough his KG-4's were and how indestructible they were. So he cued up some Rush, turned the volume up...
 
We heard the first note and three drum beats of "Tom Sawyer" before white smoke filled the room. It was that quick, and from both speakers! yikes.gif
 
After we opened the windows and let the smoke clear out, my buddy made a call to the Klipsch factory. He explained the situation to them, to which they replied, "A Carver amp? Yeah, that'll do it!" To Klipsch's credit they mailed him new drivers and crossovers, and he sent the old burned ones back to them(yes, all woofers were toast!). Only cost him shipping! What a great company!
 
I've used that TFM-45 for two decades after that, with all kinds of speakers, without a problem. I only just recently checked it for DC offset (fine), and there's no way for DC to propagate through it from the input. So it must have been just too much instantaneous voltage or current that caused those poor little KG-4's to combust. 

 

LOL! I liked that story.

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This has been a great thread to read. Welcome to the site Jim. I am glad to see you were an honest sales person. I usually know what I am looking for when I go shopping, and my experience is sales people are not as knowledgeable as they should be. I think you will feel welcome here. Have a great day,

 

BarryG

 

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I felt that every component and every system be clearly labeled with with make, model number and price.  In each system I would show what was included with the package, what the warranty coverage was, what the system discount was and that we would be glad to deliver the equipment and install it.
God bless you.  You're an admirable man.
 
If I go into a store, and the prices aren't plainly labeled, I'm probably out-the-door regardless of my interest or the likelihood that I can afford the product.  I have no time to track down a salesman so that I can beg him to tell me how much money they want for "whatever" I happen to be curious about.
 
The worst example of this is buying or servicing a car.  The "salesman" can't sell the car, he has to get "approval" from "the manager" before signing any paperwork.  I understand that the price goes up somewhat due to sales tax, but then they pile on the extras, like charging a hundred dollars to have a low-wage secretary send the title and registration paperwork to the state (Documentation Fee); or a hundred-fifty for having a low-wage car-wash boy "Detail" the car (two weeks ago, when the car went through the used-car cleanup program).   It's as outrageous as being charged "Disposal Fees" or "Shop Supplies" when paying for vehicle service work.  The restaurants I go to don't put an "Environmental Surcharge" on the tab because the grease they cook my fries in has to be filtered occasionally, and replaced periodically.
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Yes, I agree that there were a few that really knew their products back in the day, but most did not know and all the wanted to do is make a sale!

 

This is a true story:

I read all the ads on Carver gear and I used to drool over the gear in the local Hi-Fi shop but I never could afford the Carver gear. So I ended up with some Yamaha gear and Marantz speakers. Later on my home was robbed and all my stereo gear was gone..... So my insurance company tell me to go to a local appliance store and not any of the Hi-Fi shops so I was a lil disappointed. So, I'm looking around and not a big selection of audio gear until i see the Carver gear set-up! WOW, so I picked out the following: CARVER M-500t MK II amp, CARVER 4000t pre amp, CARVER TX-11a tuner and a CARVER DTL-200 cd.

 

This is where the un-educated salesman comes in:

So I go to the local Hi-Fi shop to look at speakers and this salesman is trying really hard to sell me on some Polk SDA's (the one with the umbilical cord) and I must say that I was really impressed with the sound. I don't recall what he was using to push them but they really sounded good to me, so I buy them. Upon hooking them up to my Carver gear I had problems. The ad said the M500t amp "Runs cool to the touch!", well it was getting so hot that it shut down. Very disappointed, I wrote a letter to Carver stating such and they responded the following: Thanks for your purchase in Carver, but we find that the speakers and the floating magnetic ground are incompatible!! Well, needless to say i was pissed. So I bring the letter and speakers back to the Hi-Fi shop and ask for the manager, his response was that his guy should have known better as they are not compatible. He also informed me that they were going out of business and I had to settle for a "in store" credit. The shelves were bare except for a pair of Klipsch Cornwall II's.....

 

So, that is my story!

 

Thanks,

 

RonW.

 

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...I am enjoying being part of the Carver website.  There are so many things to read and nearly all of them bring back memories of my experiences with audio, sound re-enforcement and customers.  It is abundantly clear to me that, in some ways, things haven't changed much.  The confusion about the relationship between power, volume and speaker efficiency is still one of the least understood concepts. 
 
...I have just been reading some of the posts in the amp section of the website and gritting my teeth...
 
I'm curious; I'm pretty sure everyone here has a grasp of the concept of amp power versus speaker efficiency.  Are you referring to any post(s) in particular.
 
Also, I wanted to clarify something you stated as I think I might challenge your comment if I understand it correctly.  
 

"You can then point out that you have a 600/WRMS per channel amp driving a tiny speaker, perhaps a Boston Acoustics A-40 or a Paradigm Atom which have spec sheets that say "amplifier power recommended 25-100 watts" and that the LEDs on the Carver are clearly approaching the top.  Yet, there is no distortion, no distress and other than the lack of deep bass, the speakers sound wonderful.  They will play like that for an hour before the crossover gets warm."
 
 In my experience, you can play a small speaker quite loudly, but it is physically impossible to output 600 watts into a speaker with a RMS rating of, say, 100 watts, (which would probably translate to a maximum rating of @ 300 watts for very short periods), without doing permanent damage.  Doing so will, in my experience, cause overheating damage to voice coils & other sensitive parts at a minimum.  
I agree it is perfectly possible (& preferable) to have ample amplifier reserve power over & above the speaker's rating, but the example you gave appears to be misleading....
 
I welcome your rebuttal/clarificaton!
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  • Today's Quiz

When testing the limits of their systems with high powered amplifiers, which outcome would most audiophiles prefer?

1. Blown speakers
2. Fired crossovers
3. Shorted output transistors
4. Permanent hearing damage
5. A few popped 50 cent fuses

Take your time - this is a toughie.

RR

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  • Today's Quiz

When testing the limits of their systems with high powered amplifiers, which outcome would most audiophiles prefer?

1. Blown speakers
2. Fired crossovers
3. Shorted output transistors
4. Permanent hearing damage
5. A few popped 50 cent fuses

Take your time - this is a toughie.

RR

None of the above. emsmilep.gif

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....I have just been reading some of the posts in the amp section of the website and gritting my teeth...

 

Yeah, that happens quite a bit; for example, colloquially someone might interchange efficiency and sensitivity, but in the universal language of mathematics they are entirely different concepts. 

 

I used to try to correct these errors of ignorance, but got a rep as being a tight-ass, so I usually let them slip by 

 



.....I'm curious; I'm pretty sure everyone here has a grasp of the concept of amp power versus speaker efficiency. ....

I'm not so sure that everyone has such a grasp

 

e.g. there is no such thing as a highly efficient speaker, most people that say so are talking about sensitivity which is entirely different.

 

Any electro-acoustic transducer is highly inefficient; most of the power it's exposed to is wasted as heat

 

Loudspeaker efficiency is defined as the sound power output divided by the electrical power input, and they all are inefficient.

 

Now, the portion of input that's not wasted as power is transduced from electrical current into acoustic pressure, and that's where the sensitivity of the transducer can be high or low 

 


 

The 'who has watts, the amp or the speaker?' debate is also a bit off

 

The answer is neither

 

A Watt is an SI unit of  electrical power; power is the rate at which work is done; work is force applied across a distance

 

In the case of an amplifier-loudspeaker combination, the amplifier provides a voltage to the loudspeaker, not watts

 

The loudspeaker, being the amplifier's load,  reacts to the applied voltage by producing waste heat (due to its high inefficiency) and sound pressure

 

This is where the work is done (in the voice coil) and where the voltage exposed, in combination with the load impedance of the transducer, determines the rate at which this work is done, and therefore the power consumed

 

 
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..... In my experience, you can play a small speaker quite loudly, but it is physically impossible to output 600 watts into a speaker with a RMS rating of, say, 100 watts, (which would probably translate to a maximum rating of @ 300 watts for very short periods), without doing permanent damage.  Doing so will, in my experience, cause overheating damage to voice coils & other sensitive parts at a minimum.....
 
In the OP's example, the top lights of the 600W amplifier were lit; this doesn't mean that 600W RMS was exposed to the load
 
Music has a 10-20dB peak-to-average ratio (wasn't it Paul Klipsch who said "what the world needs is a good 15 Watt amplifier"?)
 
As such, transients may be reaching 1200W (for about 15 milliseconds), but the average exposure is more like 12 watts
 
The transients will come and go before the load has time to complain, and its average exposure is within its thermal rating 
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...<Snip> The 'who has watts, the amp or the speaker?' debate is also a bit off <Snip>
 
You can't interchange the term watt with regards to power generation (electrical watt) and power consumption (work).
 
One is a measure of electrical current flow, the other is a measure of physical work or movement.  
 
An amplifier provides a continuously variable voltage to the loudspeaker, and it also sources the current to the loudspeaker as well. Therefore, an amplifier absolutely produces wattage. To insinuate otherwise is silly.
 
In your example, you imply the amplifier is not "working" because mechanical motion (work) is not being done. You go on to state that the transducer is "working" because it is moving in response to the voltage and current flow applied to it.
 
Electrical power generation wattage is defined by P =I x E. If you connect an amplifier to a straight piece of wire, current flow will occur and the wire will heat up. This is the work you speak of being done. If the amplifier increases the voltage applied, more current will flow until one of two things happens: the wire opens or the amplifier can no longer source additional current into the wire. If the amp produces voltage, it must, by definition, produce current. Current flow and the wire heating up is the work in this electrical circuit.
 
The watt rating for the transducer is related to the power consumed (converted to mechanical movement and dissipated as heat). In typical real life applications, the current flow through the transducer doesn't exceed the capacity of the wire long enough to cause an open to occur. To Rich's point, the voltage and current flow (wattage) applied to the speaker, as an average, isn't enough to destroy the transducer wiring.
 
In defense of TNRabbit, I too accept your challenge: Send me any speaker truly rated at 100 watts RMS and I will connect it to my M1.0t MKII Opt 002 amp. I will drive it with the C-1 tone controls bypassed (flat) and I guarantee you that if I set it to light the top LEDs continuously for any significant amount of time, you will be buying replacement drivers for your speaker.
 
 
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...<Snip> The 'who has watts' date=' the amp or the speaker?' debate is also a bit off <Snip>[/quote']
 
You can't interchange the term watt with regards to power generation (electrical watt) and power consumption (work).
 
You definitely can, they are analogous equations; like electrical impedance and acoustical impedance, like inductance and inertia, like capacitance and mass,  they use the same math and describe the same principle (work being done)
 
You might be confusing work (Watts, regardless of type) with Electrical energy (Watt-hours) 
 
One is a measure of electrical current flow(Watt hours), the other is a measure of work (Watts).  
 

 

.....An amplifier provides a continuously variable voltage to the loudspeaker, and it also sources the current to the loudspeaker as well. Therefore, an amplifier absolutely produces wattage. To insinuate otherwise is silly.
 
I disagree; an amplifier (in the sense of an audio amplifier) provides a voltage source (in the case of Sunfire amplifiers, an ideal voltage source) and only current proportional to its load impedance (the loudspeaker I = E/R);  no load means no current flow, no watts.  Yes, there is current flow internally, but that's considered as waste in the efficiency calculations; no watts from an amp without a load
 
Re-stated
an audio amplifier provides an output voltage proportional to its voltage input
A transconductance amplifier provides an output current proportional to its voltage input
Neither output watts 
 

 

..In your example, you imply the amplifier is not "working" because mechanical motion (work) is not being done. You go on to state that the transducer is "working" because it is moving in response to the voltage and current flow applied to it.
 
That's not explicitly what I stated; I claim no dependence upon physical motion for work consumption.  I simply stated that the work is not happening in the amp; it's the voice coil (load) that, when exposed to current flow, consumes wattage 
 

 

....Electrical power generation wattage is defined by P =I x E. If you connect an amplifier to a straight piece of wire, current flow will occur and the wire will heat up. This is the work you speak of being done. If the amplifier increases the voltage applied, more current will flow until one of two things happens: the wire opens or the amplifier can no longer source additional current into the wire. If the amp produces voltage, it must, by definition, produce current. Current flow and the wire heating up is the work in this electrical circuit.
 
Yes, this is correct. why  re-state what I said in a matter of disagreement?
 
You can see the corollary directly
 
Work = force times distance
Watts = voltage times current
voltage = force
current = distance
Watts = work 
 

 

...In defense of TNRabbit, I too accept your challenge: Send me any speaker truly rated at 100 watts RMS and I will connect it to my M1.0t MKII Opt 002 amp. I will drive it with the C-1 tone controls bypassed (flat) and I guarantee you that if I set it to light the top LEDs continuously for any significant amount of time, you will be buying replacement drivers for your speaker.
 
If you re-read the OP, you'll see that signal < about 100 Hz was also routed to a subwoofer; while the amplifier may have been at max headroom (given about 1200W peaks) the average value of voltage applied will be in the near 12W range; then exclude signal that has the potential to run the driver into over-excursion (it's relieved of bass) and I think the OPs driver would be safe (he mentions having done this demo numerous times)
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  • Today's Quiz

When testing the limits of their systems with high powered amplifiers, which outcome would most audiophiles prefer?

1. Blown speakers
2. Fired crossovers
3. Shorted output transistors
4. Permanent hearing damage
5. A few popped 50 cent fuses

Take your time - this is a toughie.

RR
 
I won't try to speak for most audiophiles- you guys are always surprising me! But for myself:
 
2. Means I have to get to and dismount a speaker, take it apart, and get stinky varnish/electrolyte on my hands before I put it all back together and in place.
 
3. Means I have to get to and dismount an amp, take it apart, and curse the scarcity and price of obsolete big silicon before I  put it all back together and in place.
 
4. Means I'll have to buy *more* amps and *more* speakers to get back *more* lost effective volume. I'm running out of room as it is!
 
5. Means instantly interrupting the music just when it's getting good. Plus it tends to have a long time constant clip-limiting compression effect as it nears blowing. 
 
On the other hand,
 
1. Means that weak driver needed to die before its excursion limits and power compression started affecting my sound quality. Bragging rights, plus now I can go get tougher, more *sensitive* speakers! party.gif
 
 
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Not sure I should even post here, I would hate to look like a school yard bully or trouble maker again but..... it seems to me that the OP is on a mission to enlighten the forum as a whole with his wisdom which to me at least comes off as just a little bit condescending considering the wealth of knowledge we have here. Certainly some of us are more knowledgeable than others when it comes to different areas of  electronics and some of us myself especially could use a bit of learning.
 
This being said not sure why the subject at hand is of great concern considering that most of us own older electronics that are not within spec unless they have been recently restored or upgraded by one of the techs here and we all know it is not a good idea to crank up the sound with an older amp putting both the amp and possibly valuable speakers at risk of damage not to mention the risk of hearing damage and the simple fact most of us even if we have restored gear do not listen to music loud enough and long enough to damage our speakers anyways.
 
 
Certainly there is a lot of  myths out there floating around on the internet that having been repeated often enough are accepted as fact regardless of whether there is any real factual evidence or truth to them. It seems to me that trying to debunk these every time you see one is like fighting with windmills a waste of time and your energy and knowledge would be better spent helping those who want the help rather than going about trying to right every incorrect statement.
 
 
Just my 2 cents carry on however you wish just an observation here.
 
REGARDS SNOW 
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