When do you need more amplifier?

[TankTop5]

Wasn’t sure if this should go in speaker or amplifier section so I put it here. I’ve heard the description that a speaker is not fatiguing to listen to but I think that might be more descriptive of the speaker/amplifier combo and listening distance/volume? My Dynaudios are currently for sale because my wife said I spent too much money but listening to them with my 40 watt NAD may not be the best idea. I listen at about 12’ and in the 80 decibel range but if I want to go any higher in volume they start to get uncomfortable to listen to, I’m guessing this is distortion or clipping from the amplifier, would that be correct?

The Dyn’s are rated at 6ohm and 200 watt max power at 86db/m

The NAD is rated 40wpc at 8ohms with dynamic power ratings in 8/4/2 ohms.

If I’m listening at 12’, without being a math whiz I think I can get into trouble real quick with this amp.

 

[Pogre]

This SPL Calculator is a pretty neat tool. You enter your amp power, speaker sensitivity and distance and it will calculate the power you need to reach whatever spl you're trying to achieve.

Your 40 watt amp is a little lean on power, but depending on sensitivity it could be enough, tho I can see an argument for more power in your situation.

*Edit: I just punched your info in and it calculated 93+ dB at your listening position. That's at the end of your power, but it's also pretty loud.

 

[Verdinut]

The Dyn’s are rated at 6ohm and 200 watt max power at 86db/m

The NAD is rated 40wpc at 8ohms with dynamic power ratings in 8/4/2 ohms.

If I’m listening at 12’, without being a math whiz I think I can get into trouble real quick with this amp.

What is the model of your NAD amplifier?

 

[Swerd]

My Dynaudios are currently for sale because my wife said I spent too much money but listening to them with my 40 watt NAD may not be the best idea. I listen at about 12’ and in the 80 decibel range but if I want to go any higher in volume they start to get uncomfortable to listen to, I’m guessing this is distortion or clipping from the amplifier, would that be correct?

Distortion or clipping would be my guess as well. The specs on your Dynaudio speakers and NAD amp suggest that too.

The question becomes, what does distortion or clipping sound like? Apparently many amp/speaker combos are under powered, and the owners aren't directly aware of it. What does clipping sound like when an amp is clipping at a low level, 10% for example? Often, it occurs for very brief moments in music, only at the peaks. What you say about your Dynaudio speakers and NAD amp remind me of that. You can't say anything is clearly wrong, but you are underwhelmed by their sound.

In my own experience, I found the differences from going from a smaller amp to a larger amp were subtle and hard to easily describe in words. A number of years ago I added an external 200 wpc amp to my existing AVR. The 2 channel amp drove my front left and right speakers. The AVR was a modest Denon rated at 70 wpc. So the power increase for the front left & right speakers was about triple, while everything else was unchanged.

At first, I couldn't say I noticed anything had changed. But soon I noticed that the speaker's bass seemed a little more crisp and firm (less bloated?) on certain musical selections. It was subtle, and depended on the music, so it wasn't always noticeable. Within a few weeks, I started noticing that the audible cues for comfortably loud sound had changed. I could listen at louder levels without noticing that it was uncomfortably loud. As a result, I started turning it down.

Apparently, with the 70 wpc AVR, I had judged when to turn it down by the amount of noise or distortion I was hearing. When I started using the bigger amp, those cues were less noticeable. It's not unlike driving a car, where I could estimate my speed by listening to the road noise. If I got new tires, or drove on smoother pavement, those cues changed and my sense of speed was off. The more powerful amp was apparently quieter, as in less noisy than the smaller amp, while at the same time, driving the speakers louder. I hope that makes sense.

Is your NAD an integrated amp or receiver that allows adding an external amp? If so, look for a used or new amp at least 120 wpc. There are often good deals on used 2 channel amps. See if that doesn't make a difference. But unlike listening to new speakers that are clearly better, don't expect the difference to be immediately noticeable.

 

[TankTop5]

What is the model of your NAD amplifier?

NAD 705

 

[highfigh]

Wasn’t sure if this should go in speaker or amplifier section so I put it here. I’ve heard the description that a speaker is not fatiguing to listen to but I think that might be more descriptive of the speaker/amplifier combo and listening distance/volume? My Dynaudios are currently for sale because my wife said I spent too much money but listening to them with my 40 watt NAD may not be the best idea. I listen at about 12’ and in the 80 decibel range but if I want to go any higher in volume they start to get uncomfortable to listen to, I’m guessing this is distortion or clipping from the amplifier, would that be correct?

The Dyn’s are rated at 6ohm and 200 watt max power at 86db/m

The NAD is rated 40wpc at 8ohms with dynamic power ratings in 8/4/2 ohms.

If I’m listening at 12’, without being a math whiz I think I can get into trouble real quick with this amp.

Speaker power ratings are almost useless- that's long-term power input, not a requirement.

There's no reason the NAD can't drive these speakers- I installed Dynaudio Audience speakers in a den, powered by a Denon AVR-987, in 2007- I changed the AVR with one that has more HDMI inputs and HEOS, but the speakers are still there and they still sound great at distances that are less than yours.

If the room has mostly hard surfaces, I would bet that the discomfort is from the reflected sound but a good thing to look at is the volume control- where is the indicator on the knob when it becomes uncomfortable? If it's above 12:00, you need more power. If you have a way to use an amp with more power without buying anything and it's still uncomfortable, I would recommend improving the room's acoustics. At 12', you should have no problem listening to Dynaudio speakers- their response is very smooth, without phase issues.

 

[Pogre]

At first, I couldn't say I noticed anything had changed. But soon I noticed that the speaker's bass seemed a little more crisp and firm (less bloated?) on certain musical selections. It was subtle, and depended on the music, so it wasn't always noticeable. Within a few weeks, I started noticing that the audible cues for comfortably loud sound had changed. I could listen at louder levels without noticing that it was uncomfortably loud. As a result, I started turning it down.

Apparently, with the 70 wpc AVR, I had judged when to turn it down by the amount of noise or distortion I was hearing.

Swerd, that is a great way to convey what the audible differences are in power when it's a big jump like that. Your experience mirrors mine.

 

[Swerd]

I cannot rule out what highfigh says. Try what he suggests and see if that leads to satisfaction. But my first guess is your speakers would do better with greater power.

With your NAD 705, you are in luck. You can easily add an external 2-channel amp. See the Pre Out and Main In jacks below. If you pull out those links, you can use the NAD 705 as a pre-amp and an external amp to drive the speakers.

 

[yepimonfire]

Distortion or clipping would be my guess as well. The specs on your Dynaudio speakers and NAD amp suggest that too.

The question becomes, what does distortion or clipping sound like? Apparently many amp/speaker combos are under powered, and the owners aren't directly aware of it. What does clipping sound like when an amp is clipping at a low level, 10% for example? Often, it occurs for very brief moments in music, only at the peaks. What you say about your Dynaudio speakers and NAD amp remind me of that. You can't say anything is clearly wrong, but you are underwhelmed by their sound.

In my own experience, I found the differences from going from a smaller amp to a larger amp were subtle and hard to easily describe in words. A number of years ago I added an external 200 wpc amp to my existing AVR. The 2 channel amp drove my front left and right speakers. The AVR was a modest Denon rated at 70 wpc. So the power increase for the front left & right speakers was about triple, while everything else was unchanged.

At first, I couldn't say I noticed anything had changed. But soon I noticed that the speaker's bass seemed a little more crisp and firm (less bloated?) on certain musical selections. It was subtle, and depended on the music, so it wasn't always noticeable. Within a few weeks, I started noticing that the audible cues for comfortably loud sound had changed. I could listen at louder levels without noticing that it was uncomfortably loud. As a result, I started turning it down.

Apparently, with the 70 wpc AVR, I had judged when to turn it down by the amount of noise or distortion I was hearing. When I started using the bigger amp, those cues were less noticeable. It's not unlike driving a car, where I could estimate my speed by listening to the road noise. If I got new tires, or drove on smoother pavement, those cues changed and my sense of speed was off. The more powerful amp was apparently quieter, as in less noisy than the smaller amp, while at the same time, driving the speakers louder. I hope that makes sense.

Is your NAD an integrated amp or receiver that allows adding an external amp? If so, look for a used or new amp at least 120 wpc. There are often good deals on used 2 channel amps. See if that doesn't make a difference. But unlike listening to new speakers that are clearly better, don't expect the difference to be immediately noticeable.

I would second this. I have often pushed my puny car stereo and heard my brother push his inefficient speakers too hard and there's a point where it begins sounding shrill, or perhaps another way to describe it is "brittle", and fatiguing. I don't have this problem on my ht setup. Turning the volume louder should result in a fuller, flatter (in term of bass and treble) sound due to the equal loudness contour of our hearing. Anything else suggests distortion, assuming reasonable levels of course.

Sent from my moto e5 play using Tapatalk

 

[PENG]

The Dyn’s are rated at 6ohm and 200 watt max power at 86db/m

The NAD is rated 40wpc at 8ohms with dynamic power ratings in 8/4/2 ohms.

If I’m listening at 12’, without being a math whiz I think I can get into trouble real quick with this amp.

Which Dyn? Regardless, if rated 6 ohms nominal, it may dip below that in certain ranges. I agree with Pogre, for speakers rated 6 hm, 200 W max, 86 dB/2.83V/m at 12' the 705 is at it's limit for sure. I would say for compressed music you are fine but for classical and jazz or anything that has 10 dB or more dynamic peaks that last longer than 20 ms, the 705 will likely produce audible distortions at you listening level. If you want SQ to improve, try sitting closer and turn the volume down to say 70-75 dB average spl.

 

[highfigh]

I would second this. I have often pushed my puny car stereo and heard my brother push his inefficient speakers too hard and there's a point where it begins sounding shrill, or perhaps another way to describe it is "brittle", and fatiguing. I don't have this problem on my ht setup. Turning the volume louder should result in a fuller, flatter (in term of bass and treble) sound due to the equal loudness contour of our hearing. Anything else suggests distortion, assuming reasonable levels of course.

Sent from my moto e5 play using Tapatalk

Car stereo have a hard limit for power output- the battery/charging voltage makes high power more difficult because it requires some kind of AC to provide higher voltage limits. With 12VDC, it will clip far sooner than it will with regular AV because the power needed in AV comes from the grid and 120VAC is almost always higher than what's needed. The shrill sound is probably from hard clipping.

Why/how would the bass and treble be flatter, when the reflections at different frequencies can cause constructive & destructive interference?

 

[highfigh]

FWIW, the Denon AVRs that have been connected to the Audience speakers were set to -10dB max volume and I have never received a comment that it wasn't loud enough. The homeowner likes loud, too. The sub takes a lot of the load away from the main speakers, but not at their second home, which also has three pairs of Dynaudio speakers (Excite 14) and they're able to do a very nice job of filling the place and the power reaching the speakers isn't really high..

 

[highfigh]

Which Dyn? Regardless, if rated 6 ohms nominal, it may dip below that in certain ranges. I agree with Pogre, for speakers rated 6 hm, 200 W max, 86 dB/2.83V/m at 12' the 705 is at it's limit for sure. I would say for compressed music you are fine but for classical and jazz or anything that has 10 dB or more dynamic peaks that last longer than 20 ms, the 705 will likely produce audible distortions at you listening level. If you want SQ to improve, try sitting closer and turn the volume down to say 70-75 dB average spl.

At 1W.channel, the speakers should be hitting their 86dB@1m mark, plus whatever is added by the room's reflections. At 8W, they should be producing 9dB higher SPL. Going to 16W and adding room reflections makes it 102dB@1m, right? How is it that an amp rated at 40W/channel would have a problem reaching clean 90dB in that room? Doesn't NAD still use soft clipping in their amps with better than average dynamic headroom?

 

[highfigh]

I cannot rule out what highfigh says. Try what he suggests and see if that leads to satisfaction. But my first guess is your speakers would do better with greater power.

With your NAD 705, you are in luck. You can easily add an external 2-channel amp. See the Pre Out and Main In jacks below. If you pull out those links, you can use the NAD 705 as a pre-amp and an external amp to drive the speakers.

View attachment 30288

Is that NAD LINK for some kind of torture?

 

[PENG]

At 1W.channel, the speakers should be hitting their 86dB@1m mark, plus whatever is added by the room's reflections. At 8W, they should be producing 9dB higher SPL. Going to 16W and adding room reflections makes it 102dB@1m, right? How is it that an amp rated at 40W/channel would have a problem reaching clean 90dB in that room? Doesn't NAD still use soft clipping in their amps with better than average dynamic headroom?

Sure, the issue is, he doesn't sit at 1 m, but 12 ft. Note that in his first post he asked:

"I listen at about 12’ and in the 80 decibel range but if I want to go any higher in volume they start to get uncomfortable to listen to, I’m guessing this is distortion or clipping from the amplifier, would that be correct?"

When he says "higher" we don't know how much higher, so I would like to be on the conservative side.

I never said anything about reaching clean 90 dB in that room, where did you get that from?

My comment about listening to 70-75 dB average for improved SQ is on the conservative side, and to avoid chance of clipping when listening to music that has 10 or more dB of dynamic peaks that last longer than 20 ms. I used 20 ms as example because NAD's dynamic rating is base on IHF.

Screen shot below shows at 12 feet, 50 W should produce about 95 dB spl, so for media contents that have 20 dB of peaks, the "clean", unclipped average spl would be 75 dB. So the answer to his question should be "yes".
Being a NAD, that unit should have soft clipping, but it is defeatable so that's something he should check, that soft clipping is engaged. Based on one measurements I have read, I think the 705 will likely do about 50 W into 6 ohms and 55 W into 4 ohms.

By the way, now that you mention it, I remember vaguely reading about the soft clip feature, that there is something about it that was revealed in one of those review/lab measurements. I don't remember what it was but will try to find it.

 

[Swerd]

The NAD 705 manual says this integrated amp has soft clipping which can be switched on or off at the rear panel.

Power is rated as follows:

Nad-705-Owners-Manual - hifi vintage
https://www.vintageshifi.com/repertoire-pdf/pdf/telecharge.php?...Nad-705...Manual...

 

[highfigh]

Sure, the issue is, he doesn't sit at 1 m, but 12 ft. Note that in his first post he asked:

"I listen at about 12’ and in the 80 decibel range but if I want to go any higher in volume they start to get uncomfortable to listen to, I’m guessing this is distortion or clipping from the amplifier, would that be correct?"

When he says "higher" we don't know how much higher, so I would like to be on the conservative side.

I never said anything about reaching clean 90 dB in that room, where did you get that from?

My comment about listening to 70-75 dB average for improved SQ is on the conservative side, and to avoid chance of clipping when listening to music that has 10 or more dB of dynamic peaks that last longer than 20 ms. I used 20 ms as example because NAD's dynamic rating is base on IHF.

Screen shot below shows at 12 feet, 50 W should produce about 95 dB spl, so for media contents that have 20 dB of peaks, the "clean", unclipped average spl would be 75 dB. So the answer to his question should be "yes".
Being a NAD, that unit should have soft clipping, but it is defeatable so that's something he should check, that soft clipping is engaged. Based on one measurements I have read, I think the 705 will likely do about 50 W into 6 ohms and 55 W into 4 ohms.

By the way, now that you mention it, I remember vaguely reading about the soft clip feature, that there is something about it that was revealed in one of those review/lab measurements. I don't remember what it was but will try to find it.


View attachment 30289

I saw the 12' distance but as I wrote, the room's reflections will definitely add to the perceived output- these speakers are very good at wide dispersion.

Let's face it- at low % of distortion, it's just not very audible. By the time it's easy to hear, the amp has run out of steam and the volume control is pointing straight up- that's the reason I mentioned the indicator.

70-75dB? Why so low? You don't seem to think this amp is capable of more than a whisper.

Don't get me wrong- I prefer to have more power than I will use, but the fact is, these speakers can and will sound very good with a 50W/channel amplifier, especially one that is rated for 3.5dB of dynamic headroom. Look at the chart in Swerd's link- 10dB peaks at 5W average won't be a problem.

Also, you only entered one as the number of speakers and the result for two is 97.7dB. If he uses a good sub, 95dB is pretty loud. Without a sub, it won't have the impact, but should still sound very good.

 

[Swerd]

To put a price on all this, I did a quick search for what I consider good quality, affordable 2-channel external amps in the range of 110-150 wpc (continuous power at 8 ohms, 20 Hz-20 kHz, <1% THD, unless otherwise noted) and came up with these:

USED at Audiogon
B&K ST2140, 140 wpc (measured at 1 kHz),$350
Parasound Halo A23 Stereo Power Amplifier, 125 wpc, $588
Audio by Van Alstine Synergy 300 Stereo Power Amplifier, 150 wpc, $1096

NEW
Parasound NewClassic 2125v2 Power Amplifier, 150 wpc, $599 at Audio Advisor
Marantz MM7025 2-Ch, 140 wpc, $599 at Accesories4less
Audio by Van Alstine Vision SET 120, 120 wpc, $899
Odyssey Khartago Stereo Amp, 110 wpc, $995

 

[PENG]

I saw the 12' distance but as I wrote, the room's reflections will definitely add to the perceived output- these speakers are very good at wide dispersion.

Let's face it- at low % of distortion, it's just not very audible. By the time it's easy to hear, the amp has run out of steam and the volume control is pointing straight up- that's the reason I mentioned the indicator.

The calculator I used, linked, does allow for room gain, if you read the fine print.

You don't have to convince me about the audibility of "low" distortion as I am a believer too. Just don't forget what the OP himself has told us, and I repeat (okay for the last time): "I listen at about 12’ and in the 80 decibel range but if I want to go any higher in volume they start to get uncomfortable to listen to, I’m guessing this is distortion or clipping from the amplifier, would that be correct? "

70-75dB? Why so low? You don't seem to think this amp is capable of more than a whisper.

May be to you, but 75 dB is hardly whisper to me. It is loud enough that it is the level I listen to most of the time, and I am sure I have hearing loss. Anyway, that's just my opinion based on the information provided, not facts..

Besides, I would have recommended 80 dB, he's already listening in the 80 range after all so yes he won't likely be happy with 75. As I mentioned, I tried to be more conservative, since he indicated in the 80 dB range he's near the limit in terms "comfort..".

Don't get me wrong- I prefer to have more power than I will use, but the fact is, these speakers can and will sound very good with a 50W/channel amplifier, especially one that is rated for 3.5dB of dynamic headroom. Look at the chart in Swerd's link- 10dB peaks at 5W average won't be a problem.

You seem to keep missing the fact that I wanted to allow for the often recommended 20 dB dynamic peaks. IOW, if the average is 85, and the OP is already listening at the 80 range, then he may be getting audible distortions during the odd peaks above 95 dB and the occasional peaks potentially up to or even exceed 105 dB. NAD's soft clipping may soften the harshness, but not eliminate it entirely. And I guess I have to emphasis that the specified dynamic rating is based on IHF, its stated clearly in the Owner's manual. That's why I mentioned earlier that my comments were based on peaks longer than 20 ms. It is debatable whether 20 ms is long enough for it to be realistically useful, I don't know the answer but here's a link for some interesting reading:

https://books.google.ca/books?id=-5UPyE6dcWgC&pg=PA306&lpg=PA306&dq=is+ihf+standard's+20+ms+long+enough+for+music&source=bl&ots=wxImqnyIe_&sig=ACfU3U2RLTrjPwDIq9cQ8F9WH0iYr1K-6g&hl=en&sa=X&ved=2ahUKEwi_3uyGq9jjAhUTG80KHWovAM4Q6AEwAXoECAkQAQ#v=onepage&q=is ihf standard's 20 ms long enough for music&f=false

Also, you only entered one as the number of speakers and the result for two is 97.7dB. If he uses a good sub, 95dB is pretty loud. Without a sub, it won't have the impact, but should still sound very good.

I used to enter 2 speakers too for stereo and 7 for 7.1 etc, until I was corrected, by @yepimonfire if I remember right, or someone else if not him, that by THX standard, the 85 dB average, 105 dB peak thing was based on "each speaker", i.e. one at a time. We don't have to agree on the merit obviously as it is just a standard. In fact, personally I would agree with you on this.

The bottom line is, the OP told us at higher volume he's getting uncomfortable......., and I would concede that it may not be from the amplifier, though it seems likely it is, because he's only getting uncomfortable if he go higher in volume. Another thing to consider is, the NAD 705, unless refurbished, would be 27 years old, so it may be getting tired and is telling the OP its deserves an early retirement.

 

[PENG]

As promised, found one side effects of NAD's soft clipping feature, revealed in a Stereophile review on the C372, a very powerful NAD integrated amp.

In that case, the power output was reduced from the measured 190 W to 125 W to 8 ohms when soft clipping was engaged. For those not interested in reading the whole review, JA found that:

At clipping (1% THD+N),the NAD gave out 190W with both channels driven (22.8dBW),slightly higher than the specified 180W. Engaging Soft Clipping increased the distortion above a few watts output due to the waveform rounding that occurs, and reduced the continuous 1% power to 125W into 8 ohms (21dBW, fig.4, upper trace).

Read more at https://www.stereophile.com/content/nad-c-372-integrated-amplifier-measurements#msvmlOf52WiJy30R.99