Amp for DynAudio Audience speakers

[TLS Guy]

570 viewings to this post

I see this post has been viewed by 570 times. This is a topic that surfaces in various forms all the time. I wonder if some of the people viewing this thread could provide us contributors with a little feedback. In particular if the technical explanations are understandable.

Of course the principle obligation is to the OP. However his situation has allowed us to work through a real world situation involving a topic about which there seems to be continuous misunderstanding. I for one, would like feedback on the intelligibility or otherwise of this thread, and it usefulness to those who have or are viewing it.

 

[jostenmeat]

I see this post has been viewed by 570 times. This is a topic that surfaces in various forms all the time. I wonder if some of the people viewing this thread could provide us contributors with a little feedback. In particular if the technical explanations are understandable.

Of course the principle obligation is to the OP. However his situation has allowed us to work through a real world situation involving a topic about which there seems to be continuous misunderstanding. I for one, would like feedback on the intelligibility or otherwise of this thread, and it usefulness to those who have or are viewing it.

I've read through this thread before, do not recall every bit, but I found it very informative TLS. You've brought up facets on the need for power that I never knew of, or considered, and the "technical explanations" are simple enough for the layman, I believe. (I don't always get what you're saying, but in this thread I do).

Keep it up TLS, I for one appreciate it. I know you may have strong opinions on certain aspects that may differ from others, but I'm always interested in what you have to say, regardless. Cheers.

 

[PENG]

So how does this compare to Harman Kardon flagship receiver that is capable of 65 Amperes Current or the Denon PMA2000IVR which is capable of 120 Amperes Current?

http://usa.denon.com/pma2000_productsheet.pdf

Are these totally different things?

The specs of some HK flag ship stated clearly the +- 60 to 75A rating is "instantaneous". My interpretation of this spec is that the +-75A is a peak value for the total of all 7 channels (driven simultaneously) or +-10A per channel for a very short time interval, not continuous, far from it.

So no, it is not the same thing. I believe TLS was talking about continuous RMS values, not instantaneous peak values, huge difference.

 

[Davemcc]

I see this post has been viewed by 570 times. This is a topic that surfaces in various forms all the time. I wonder if some of the people viewing this thread could provide us contributors with a little feedback. In particular if the technical explanations are understandable.

Of course the principle obligation is to the OP. However his situation has allowed us to work through a real world situation involving a topic about which there seems to be continuous misunderstanding. I for one, would like feedback on the intelligibility or otherwise of this thread, and it usefulness to those who have or are viewing it.

I'm not a math and science kind of guy. As soon as the numbers and formulae appear, my eyes glaze over and my mind wanders. I'm pretty sure I get the general concept and your specific examples help to put things in perspective. I just hope you're available if this ever becomes an issue of concern for me.

Speaking of which, how does the Rotel RMB-1075 match up with the Dynaudio Focus 140? Should I be looking at an amp upgrade?

 

[AcuDefTechGuy]

I see this post has been viewed by 570 times. This is a topic that surfaces in various forms all the time. I wonder if some of the people viewing this thread could provide us contributors with a little feedback. In particular if the technical explanations are understandable.

Of course the principle obligation is to the OP. However his situation has allowed us to work through a real world situation involving a topic about which there seems to be continuous misunderstanding. I for one, would like feedback on the intelligibility or otherwise of this thread, and it usefulness to those who have or are viewing it.

I think I get the basics or "plain English" version, but I don't get a lot of the technical numbers - like the electrical physics and units (Current, Voltage, etc.) and how they relate to basic speakers and amps/preamps.

But overall, most explanations are excellent.

So Current is the Square Root of the Watts Divided by Ohms?

Example: 400 watts into 1 ohms --> 400/1 = 400. Then S.R. of 400 = 20 Amperes or 20A. So the Current is 20A per channel?

I think what I would like to see is the Take-Home Message.

For example, is the take-home message something like:

Amplifiers need to be able to handle the speakers, like the minimum impedance load? And minimum Current? Which is 3A or 4A? When this is taken care of, most amplifiers should sound neutral and not impart a sound of their own?

 

[TLS Guy]

I'm not a math and science kind of guy. As soon as the numbers and formulae appear, my eyes glaze over and my mind wanders. I'm pretty sure I get the general concept and your specific examples help to put things in perspective. I just hope you're available if this ever becomes an issue of concern for me.

Speaking of which, how does the Rotel RMB-1075 match up with the Dynaudio Focus 140? Should I be looking at an amp upgrade?

The published specs on the Focus range is sparse, but I know those drivers. The Rotel is a good match for them and has adequate current reserve. There is no point in changing amps.

Unfortunately these issues lie in the realm of electrical engineering, and some simple math is required to understand it. Published specs of speakers are usually wholly inadequate, and amp and especially receiver specs are often no better. The whole thing then becomes prone to error. Amp and receiver manufacturers need to publish max output current and into what load and for how long before it self destructs. If speaker manufacturers would publish their impedance curves, together with the phase response curve, showing the phase angle between current and voltage with frequency, then there would be no need for guessing or error.

Speaker revues do not even provide this information and they should.

 

[TLS Guy]

I think I get the basics or "plain English" version, but I don't get a lot of the technical numbers - like the electrical physics and units (Current, Voltage, etc.) and how they relate to basic speakers and amps/preamps.

But overall, most explanations are excellent.

So Current is the Square Root of the Watts Divided by Ohms?

Example: 400 watts into 1 ohms --> 400/1 = 400. Then S.R. of 400 = 20 Amperes or 20A. So the Current is 20A per channel?

I think what I would like to see is the Take-Home Message.

For example, is the take-home message something like:

Amplifiers need to be able to handle the speakers, like the minimum impedance load? And minimum Current? Which is 3A or 4A? When this is taken care of, most amplifiers should sound neutral and not impart a sound of their own?

Please see my reply to Davemcc and see why a simple take home message is impossible. In the OP's case we had the information we needed to be more precise, and that is what is usually lacking. The only take home message is that the customer can get short changed due to no fault of his own.

 

[TLS Guy]

The specs of some HK flag ship stated clearly the +- 60 to 75A rating is "instantaneous". My interpretation of this spec is that the +-75A is a peak value for the total of all 7 channels (driven simultaneously) or +-10A per channel for a very short time interval, not continuous, far from it.

So no, it is not the same thing. I believe TLS was talking about continuous RMS values, not instantaneous peak values, huge difference.

That is correct. I did not check the HK spec but the Denon spec was in the narrative and a little vague, but I think the 160 amps referred to the instantaneous peak power available from the power supply, which is not particularly relevant information, without knowing the whole design concept. I think it was a number used to impress by the "glossy" writer.

 

[TLS Guy]

I've read through this thread before, do not recall every bit, but I found it very informative TLS. You've brought up facets on the need for power that I never knew of, or considered, and the "technical explanations" are simple enough for the layman, I believe. (I don't always get what you're saying, but in this thread I do).

Keep it up TLS, I for one appreciate it. I know you may have strong opinions on certain aspects that may differ from others, but I'm always interested in what you have to say, regardless. Cheers.

Thanks for the feedback. That is the information I'm looking for. If there is something that needs clarification please ask.

 

[Davemcc]

The published specs on the Focus range is sparse, but I know those drivers. The Rotel is a good match for them and has adequate current reserve. There is no point in changing amps.

Unfortunately these issues lie in the realm of electrical engineering, and some simple math is required to understand it. Published specs of speakers are usually wholly inadequate, and amp and especially receiver specs are often no better. The whole thing then becomes prone to error. Amp and receiver manufacturers need to publish max output current and into what load and for how long before it self destructs. If speaker manufacturers would publish their impedance curves, together with the phase response curve, showing the phase angle between current and voltage with frequency, then there would be no need for guessing or error.

Speaker revues do not even provide this information and they should.

Thanks for the info. I have been thinking of getting another amp but I guess it's not as big an issue as I thought.

 

[TLS Guy]

Thanks for the info. I have been thinking of getting another amp but I guess it's not as big an issue as I thought.

I don't think what ever amp you buy, your speakers will sound any better. Your current amp will drive them to their max spl.

If you want improvement you will have to move up the food chain in terms of speakers.

 

[SpunkyDDog]

Of course the principle obligation is to the OP. However his situation has allowed us to work through a real world situation involving a topic about which there seems to be continuous misunderstanding. I for one, would like feedback on the intelligibility or otherwise of this thread, and it usefulness to those who have or are viewing it.

Well, I'm hoping I'm not a pain in the rear, but it seems you all tolerated my questions and postings. )

To your question/request regarding feedback: your posts, and many others, have been technical/understanding enough for me to understand where you're getting the numbers. I'm a little lost on the Amps/Current deal, but I have the gist (?). I guess the only thing I'm lost on regarding current is how do you know if the numbers you got from the amp will work for the speakers you're driving and when is it good to have enough headroom?

Well, let me give another real world scenario with some related info as I mentioned I would post earlier. So my CFO/Lovely wife approved of the borrowed sum of $500-$800 (I might even be able to go out still to get GTA IV ). So I've been pretty much set on buying either the Emotiva XPA-5 or the LPA-1. Listening to yours and other posters' suggestions, I learned that headroom would be good for power output (obviously) and the fact that a larger amp would probably last longer over the long run if I'm running all channels at higher volumes constantly, or playing a lot of opera/classical/orchestra (which is not far from my taste).

I almost bought the XPA-5; in fact, just 5 minutes ago I clicked out of the browser thinking to myself that I should be sure to think about it one last time. So, I thought to myself, "What's the difference really and would more wpc be worth the extra $300?" Well, looking at the numbers:

(From these sites: http://www.emotiva.com/xpa5.html and http://www.emotiva.com/lpa1.html)

LPA-1 offers 5 channels - 4 Ohm @ 225wpc and 2 channels @ 95wpc
XPA-5 offers 5 channels - 4 Ohm @ 350wpc

(If all calculations are correct...)

LPA-1 offers 7.5a per 5 channels and 4.87a per 2 channels with THD 0.04%
XPA-5 offers 9.35a per 5 channels with THD 0.007%

(Looking at the Dynaudio Audience 72 specs: http://www.dynaudiousa.com/products/audience/72/aud72spec.htm)

((210w IEC long-term Power Handling) / 7.8 ohms) ^ 0.5 = 5.18a
((210w IEC long-term Power Handling) / 3.1 ohms) ^ 0.5 = 8.2a

So these calculations result in a fluctuating current of 5.18a to 8.2a, of which I need to use to figure out how/what will drive the speakers sufficiently to its max wattage handling? So if I want an amp to drive these speakers at 8.2a, it seems the XPA-5 would more than enough? Am I missing something else in the number game or do I have the idea?

I know looking at the THD alone that the XPA-5 would make an orchestra's cello sound more like a cello; therefore, theoretically, making it a better choice on just that number, much less the wattage, if I was only going for clarity & quality. But the problem I have now is worrying if I'll need more current to power my speakers (?), much less be able to hold stable at a low 3.1 Ohms. I contacted Emotiva, but they have not replied to my inquiry, though it might need to take a little while before they get to it.

I'm a little eager to purchase since after Monday, hopefully, my damn "bad" carpet will be replaced and I'll be able to put my life back in order. I've been eating out for the past several days since I've moved almost every piece of furniture into my kitchen and bathrooms. Essentially, I only have 2 electronics hooked up: my laptop and wireless router. I decided the other day to calm down and not bother with hooking up my Yamaha RX-V663 this weekend just to play with my "new to me" Dynaudio Audience 72s. I think it's better to be safe and wait for the amp I guess...

 

[TLS Guy]

Well, I'm hoping I'm not a pain in the rear, but it seems you all tolerated my questions and postings. )

To your question/request regarding feedback: your posts, and many others, have been technical/understanding enough for me to understand where you're getting the numbers. I'm a little lost on the Amps/Current deal, but I have the gist (?). I guess the only thing I'm lost on regarding current is how do you know if the numbers you got from the amp will work for the speakers you're driving and when is it good to have enough headroom?

Well, let me give another real world scenario with some related info as I mentioned I would post earlier. So my CFO/Lovely wife approved of the borrowed sum of $500-$800 (I might even be able to go out still to get GTA IV ). So I've been pretty much set on buying either the Emotiva XPA-5 or the LPA-1. Listening to yours and other posters' suggestions, I learned that headroom would be good for power output (obviously) and the fact that a larger amp would probably last longer over the long run if I'm running all channels at higher volumes constantly, or playing a lot of opera/classical/orchestra (which is not far from my taste).

I almost bought the XPA-5; in fact, just 5 minutes ago I clicked out of the browser thinking to myself that I should be sure to think about it one last time. So, I thought to myself, "What's the difference really and would more wpc be worth the extra $300?" Well, looking at the numbers:

(From these sites: http://www.emotiva.com/xpa5.html and http://www.emotiva.com/lpa1.html)

LPA-1 offers 5 channels - 4 Ohm @ 225wpc and 2 channels @ 95wpc
XPA-5 offers 5 channels - 4 Ohm @ 350wpc

(If all calculations are correct...)

LPA-1 offers 7.5a per 5 channels and 4.87a per 2 channels with THD 0.04%
XPA-5 offers 9.35a per 5 channels with THD 0.007%

(Looking at the Dynaudio Audience 72 specs: http://www.dynaudiousa.com/products/audience/72/aud72spec.htm)

((210w IEC long-term Power Handling) / 7.8 ohms) ^ 0.5 = 5.18a
((210w IEC long-term Power Handling) / 3.1 ohms) ^ 0.5 = 8.2a

So these calculations result in a fluctuating current of 5.18a to 8.2a, of which I need to use to figure out how/what will drive the speakers sufficiently to its max wattage handling? So if I want an amp to drive these speakers at 8.2a, it seems the XPA-5 would more than enough? Am I missing something else in the number game or do I have the idea?

I know looking at the THD alone that the XPA-5 would make an orchestra's cello sound more like a cello; therefore, theoretically, making it a better choice on just that number, much less the wattage, if I was only going for clarity & quality. But the problem I have now is worrying if I'll need more current to power my speakers (?), much less be able to hold stable at a low 3.1 Ohms. I contacted Emotiva, but they have not replied to my inquiry, though it might need to take a little while before they get to it.

I'm a little eager to purchase since after Monday, hopefully, my damn "bad" carpet will be replaced and I'll be able to put my life back in order. I've been eating out for the past several days since I've moved almost every piece of furniture into my kitchen and bathrooms. Essentially, I only have 2 electronics hooked up: my laptop and wireless router. I decided the other day to calm down and not bother with hooking up my Yamaha RX-V663 this weekend just to play with my "new to me" Dynaudio Audience 72s. I think it's better to be safe and wait for the amp I guess...

Either one would do a good job. However, I can tell you that now and again you would probably clip the LPA-1, and spoil a big moment. The XPA-5 has power to spare. That is the position I prefer to be in. For two channel listening the XPA-5 has a maximum current delivery of 10.6 amps, for three channel listening, all channels fully driven, 10 amps. In the highly unlikely event you drove all 5 channels to the max you would have 9.4 amps. For practical purposes you have more than enough power. You may remember that 9.5 amps will deliver at least 250 watts to you speakers, under a worst case scenario. That is plenty!

I would go with the XPA-5. I think that will give you years of service. Please let us know how it sounds.

 

[PENG]

((210w IEC long-term Power Handling) / 7.8 ohms) ^ 0.5 = 5.18a
((210w IEC long-term Power Handling) / 3.1 ohms) ^ 0.5 = 8.2a

So these calculations result in a fluctuating current of 5.18a to 8.2a, of which I need to use to figure out how/what will drive the speakers sufficiently to its max wattage handling? So if I want an amp to drive these speakers at 8.2a, it seems the XPA-5 would more than enough? Am I missing something else in the number game or do I have the idea?

I'm a little eager to purchase since after Monday, hopefully, my damn "bad" carpet will be replaced and I'll be able to put my life back in order. I've been eating out for the past several days since I've moved almost every piece of furniture into my kitchen and bathrooms. Essentially, I only have 2 electronics hooked up: my laptop and wireless router. I decided the other day to calm down and not bother with hooking up my Yamaha RX-V663 this weekend just to play with my "new to me" Dynaudio Audience 72s. I think it's better to be safe and wait for the amp I guess...

Your could add another 13% to the current you calculated in order to account for the 28 degree phase shift (Cosine 28 degree=0.883). Without seeing the actual Impedance vs Frequency and Current Phase Shift vs Frequency curves it is not possible to tell whether the lowest impedance and maximum phase shift occurs at the same frequency. Again, 28 degree phase shift is not too much of a problem as it result in an extra 13% of current only.

Note that the worst, or near worst case scenarios may or may not occur at the frequencies that require high transient power/current in certain music, e.g. when the bass drums and/or timpani hit hard. It is difficult (if even possible) to answer your questions because it depends on so many variables, some technical, some a matter of your preference and habits.

In my opinion, any well made power amps rated for 400 WPC continuous, should get you adequate head room. It is good to have more, just to be 110% sure, but you may never need it.

 

[PENG]

I learned that headroom would be good for power output (obviously) and the fact that a larger amp would probably last longer over the long run if I'm running all channels at higher volumes constantly, or playing a lot of opera/classical/orchestra (which is not far from my taste).

I missed this part in my last response. Please note that your speaker's long term power handling rating is only 210 watts, so if you are going to be running all channels at higher volumes constantly you should make sure you do not end up overpowering the speakers. Practically speaking, you are naturally protected because at that level you will likely be subjected to a constant SPL of around 100 dB based on your room size and you will therefore be wearing hearing protection (but why would you do it then?).

If you listen to classical music, you will be fine because they typically demand lots of power for short intervals only. In that case, your speakers will become the limiting factor, not your amp. So if you feel wanting more when playing classical music then it is time to see your CFO again for speaker upgrades. Your 400 WPC amplifier will still be good for the larger Dynaudio speakers.

By the way, unless you get the amp, why not try out the RX-V663. At moderate listening volume it will do fine, just keep an eye on it and check that it doesn't get too hot and be sure to crossover at 80 Hz if you watch movies with a subwoofer.

 

[TLS Guy]

I missed this part in my last response. Please note that your speaker's long term power handling rating is only 210 watts, so if you are going to be running all channels at higher volumes constantly you should make sure you do not end up overpowering the speakers. Practically speaking, you are naturally protected because at that level you will likely be subjected to a constant SPL of around 100 dB based on your room size and you will therefore be wearing hearing protection (but why would you do it then?).

If you listen to classical music, you will be fine because they typically demand lots of power for short intervals only. In that case, your speakers will become the limiting factor, not your amp. So if you feel wanting more when playing classical music then it is time to see your CFO again for speaker upgrades. Your 400 WPC amplifier will still be good for the larger Dynaudio speakers.

By the way, unless you get the amp, why not try out the RX-V663. At moderate listening volume it will do fine, just keep an eye on it and check that it doesn't get too hot and be sure to crossover at 80 Hz if you watch movies with a subwoofer.

He will be fine. Those little drivers are conservatively rated. The voice coils are large and vented. He will have all the spl he needs. The bass response is good. When he gets his sub, I would set your mains to large and supplement from about 60 Hz down with the sub. Guard against having the sub too loud. Those drivers will take everything Hollywood sends their way. I have never come close to frying one of those drivers and I have used them under demanding professional conditions.

 

[AcuDefTechGuy]

LPA-1...with THD 0.04%...
XPA-5...with THD 0.007%...

...looking at the THD alone that the XPA-5 would make an orchestra's cello sound more like a cello; therefore, theoretically, making it a better choice on just that number...

I think everyone will agree that you will NOT hear any differences whatsover between the 0.04% & 0.007% THD.

Humans have hearing thresholds when it comes to THD, SNR, Crosstalk, F.R. Linear deviations.

Maybe we can get this squared away.

My impression is that the threshold for THD is 1% (20Hz-20kHz), SNR is 80dB (20Hz-20kHz), Crosstalk is - 30dB (20Hz-20kHz), and Linear deviation is 20Hz-20kHz +/- 1dB? So anything better than these numbers will not result in better sound quality?

Am I close?

 

[TLS Guy]

I missed this part in my last response. Please note that your speaker's long term power handling rating is only 210 watts, so if you are going to be running all channels at higher volumes constantly you should make sure you do not end up overpowering the speakers. Practically speaking, you are naturally protected because at that level you will likely be subjected to a constant SPL of around 100 dB based on your room size and you will therefore be wearing hearing protection (but why would you do it then?).

If you listen to classical music, you will be fine because they typically demand lots of power for short intervals only. In that case, your speakers will become the limiting factor, not your amp. So if you feel wanting more when playing classical music then it is time to see your CFO again for speaker upgrades. Your 400 WPC amplifier will still be good for the larger Dynaudio speakers.

By the way, unless you get the amp, why not try out the RX-V663. At moderate listening volume it will do fine, just keep an eye on it and check that it doesn't get too hot and be sure to crossover at 80 Hz if you watch movies with a subwoofer.

The thing is that when you look at a power spectrum meter, as I do when doing editing and archiving work, the power frequency energy spectrum is all over the map. Unless the OP plays continuous sine waves he will not blow his speakers. The issue is, he needs to have enough power for the huge rush of chorus over orchestra, or a sudden dramatic orchestration in opera. There are numerous parts in classical scores were the energy spectrum suddenly and briefly shoots off the clock.

For me an amp running out of gas at such a moment really spoils the performance. If he listens to compressed hard rock he will be deaf before the drivers blow, I promise you. However I'm certain the OP is not that kind of lunatic. You can tell by his posts, he and his wife are sensible people.

 

[PENG]

The thing is that when you look at a power spectrum meter, as I do when doing editing and archiving work, the power frequency energy spectrum is all over the map. Unless the OP plays continuous sine waves he will not blow his speakers. The issue is, he needs to have enough power for the huge rush of chorus over orchestra, or a sudden dramatic orchestration in opera. There are numerous parts in classical scores were the energy spectrum suddenly and briefly shoots off the clock.

For me an amp running out of gas at such a moment really spoils the performance. If he listens to compressed hard rock he will be deaf before the drivers blow, I promise you. However I'm certain the OP is not that kind of lunatic. You can tell by his posts, he and his wife are sensible people.

Exactly, that's pretty much what I said, except that I did want to make the point that a well made 400 WPC amp has the power to blow the drivers without clipping. And of course a sensible person such as the OP will not risk damaging his speakers. Basically it is the constant high volume that we need to be concerned about. Both the amp and the speaker can handle very high instantaneous currents.

I actually measured (and posted) the current output by my 3805, a 200W (350W 4 ohms) Adcom and a 300W (500W 4 ohms) Bryston 4B SST, they all produced peak currents in excess of 10A when the bass drum hit 90+ (too long ago I can't remember the exact numbers) dB at approximately 2m from the speaker. I could not hear any sign of clipping by any of them, not even the 3805. So do not think for a moment that a lesser amp will automatically clip when the going gets tough. It depends on many factors, one being the "duration" of the high power/current demand period. Again, well made amps, like well made speakers, can also handle much high instantaneous power/currents. Besides, a little bit of clipping during the low frequencies reproduction is not going to be that audible.

 

[TLS Guy]

Exactly, that's pretty much what I said, except that I did want to make the point that a well made 400 WPC amp has the power to blow the drivers without clipping. And of course a sensible person such as the OP will not risk damaging his speakers. Basically it is the constant high volume that we need to be concerned about. Both the amp and the speaker can handle very high instantaneous currents.

I actually measured (and posted) the current output by my 3805, a 200W (350W 4 ohms) Adcom and a 300W (500W 4 ohms) Bryston 4B SST, they all produced peak currents in excess of 10A when the bass drum hit 90+ (too long ago I can't remember the exact numbers) dB at approximately 2m from the speaker. I could not hear any sign of clipping by any of them, not even the 3805. So do not think for a moment that a lesser amp will automatically clip when the going gets tough. It depends on many factors, one being the "duration" of the high power/current demand period. Again, well made amps, like well made speakers, can also handle much high instantaneous power/currents. Besides, a little bit of clipping during the low frequencies reproduction is not going to be that audible.

We are in total agreement except for the last sentence. However you are dealing with an unashamed obsessional fanatic!