Can you really damage speakers with a "powerful" amp?

gadgetluvr

Active Member
I've just ordered the the Denon AVR-X2700H and Wharfedale DX-2 (5.1 setup) package on the recommendation of a well known retailer. I wasn't aware you had to match amps to speakers, and now I'm worried the amp might be too powerful and will damage my speakers.

I (now) understand connecting speakers to an amp that's a lot more powerful than what the speakers can handle results in the speakers unable to dissipate the heat/power being generated by the amp, which then burns up the voice coil and suspension in the speaker - and destroys it. The amp puts out 150W per channel, the speaker specs state "Recommended amplifier power 20-60W".

Is this a real issue? If I want to keep the speakers (they were the cheapest 5.1 speakers I could find!) is there any way I can mitigate the issue?

Many thanks in advance.
 

kbfern

Distinguished Member
In a 5.1 speaker system connected to an x2700 there will be no problem.

The max the denon will be putting out will be around 60 watts per chanel

You will not do any damage to the speakers as you would hear distortion if you were driving them to loud and would then lower the max volume.

There are also volume limits you can set in the avr menu if you want to be catious.
 

gadgetluvr

Active Member
Oh that's a relief, thank you! May I ask how you worked out the 60W/channel figure?

I'll also investigate the volume limits you have suggested. My understanding intially was you might not always hear the distortion if the amp was delivering too much power but you could still be damaging the speaker elements.
 

Gasp3621

Distinguished Member
My understanding intially was you might not always hear the distortion if the amp was delivering too much power but you could still be damaging the speaker elements.

If you are worried that the speakers will be damaged can we assume you listen loud typically? Why i mention this is cause few owners of DX2 has said that the speaker limits will be heard when pushed loud and i could sense some disappointment. They are rather small sealed cabinets with tiny 3" drivers so not really ideal for high SPL in first place. Small room with the speakers wall mounted/against walls and moderately loud levels should be ideal for them.

Problem is av-receiver manufacturer shows you so many figures in the spec sheet and you have looked the wrong one which is 1 speaker driven for higher distortion 6ohm load.
 

kbfern

Distinguished Member
The spec of the Denon X2700 is 95w per channel into 8 Ohm with 2 channels driven so with 5 channels driven this will drop even lower (around 60w max) no maths applied here.
 

noiseboy72

Distinguished Member
"Power" kills speakers in 2 ways. The most common is due to high distortion, which creates much larger proportions of high frequency information, much of it clipped, so that the high frequency driver overheats or simply fails due to excessive voltage generating excessive current through the voice coil.

The 2nd way is due to a clean high power signal causing the voice coils either to heat up and burn out or to be pushed out of the magnetic flux field due to over excursion. Once the coil leaves the magnetic circuit it becomes a simple resistive coil instead of a motor and quickly fails. This heating effect takes minutes to affect the speakers, unlike distortion which might only need a few seconds at very severe levels

You would be very lucky to find any domestic hifi amplifier that can cause scenario 2. It only really happens when you are over driving the speaker by a factor of 5 or more. Av amps are limited by their power supply and although I would argue that "all channels driven" is not a true indication of their maximum usuable power any more than just quoting the stereo figure is, clipping and distortion is what would kill the speakers if left unchecked.

Most problems occur during parties and system "testing" when the distortion is largely ignored until the following use when the damage becomes clear.

Occasional peaks and brief distortion while you reach for the volume control in a hurry are unlikely to cause any damage- and in most domestic settings that sort of volume level is unlikely to be tolerated for long.

In short, I really wouldn't worry. You can never fully protect a domestic amplifier from abuse, but 99% of the time its just not an issue. Most damage occurs when people crank the volume to see what their system can do, so don't do this and just enjoy listening to it at a reasonable and comfortable volume :)
 

Joe Fernand

Distinguished Member
AVForums Sponsor
You can ‘kill’ loudspeaker drivers with any amp if you play movies/music at daft levels.

You don’t say what size your room is and what your expectation of the system is.

Joe
 

Gasp3621

Distinguished Member
The spec of the Denon X2700 is 95w per channel into 8 Ohm with 2 channels driven so with 5 channels driven this will drop even lower (around 60w max) no maths applied here.

Yes that is quite close for lower distortion and maybe it (60w) sounds low for someone as we see these 150w stickers in the front display of av-receivers. But also how usefull the all channels driven figure is to real life material: movies. Well most professionals says less so cause not all channels won´t be driven continuosly long times like in the test situation playing sine wawe. Mostly short times and there is good amount of peak power available. Also some people forget that subwoofer takes care the most power hungry range with it`s own amp. If the speakers would be larger and more efficient with higher sensitivity in small-med sized room this Denon should be able to play so loud that normal people (not you :D ) would most likely run out of room before nearing the limits.


The X2700H is no slouch for low price. Audio Vision (de) measured for 2600H which is same:


95w for 5channels driven 4ohm load
150w for 2channels driven 4ohm load, ASR measured 136w for rated lower distortion 2ch driven 4ohm and even more when the distortion isn´t limited, peak power over 200w for 2channels 4ohm.

This shows that Denon doesn´t skimp on the powersupply in the 600$ range model either. X2700H isn´t actually low budget model like it usually is seen in UK. In US Denon has S range models below X1600H.


DX2 speakers spoken here has nominal impedance of 4ohm as the aim was to make them more efficient.
 

Conrad.

Moderator
I've had two experiences here.

One was when I caused a feedback loop from my PC by clicking the "listen to this device" checkbox by accident. This sent what I can only imagine was a 5kHz sine wave at full power into both channels. That burnt out both my tweeters in seconds. Speakers rated as 50-120w, amp rated as 300wpc into 8ohms.

The other was when I was testing using an external DAC after my pre amp. I forgot that my digital outputs on my pre-amp were at line level and hooked up the DAC without putting it into pre-amp mode first thereby bypassing all volume control and sending a line level signal into the power amp.

This time no damage, but very loud music for a few seconds (and of course, being line level, adjusting the pre-amp volume did nothing). In this case speakers rated at 50-500W (Much larger floorstanders) and amp rated at 350wpc into 8ohms.

I'm guessing this would have blown bookshelves, but then if I had bookshelves I wouldn't need such a powerful amp.
 

kbfern

Distinguished Member
@Gasp3621 thanks for pointing out his speakers are 4 Ohm, I had looked but could not find that info.

That being the case in this instance maybe the OP could set the X2700 to 4 Ohm output and that will slash the amps output and thereby reduce any chance of his avr from providing too much power.


Of course apart from this the owner does have control of the volume control and also as previously suggested can set limits on volume from within the menu settings.

 

gadgetluvr

Active Member
Many thanks for all your replies, I do appreciate your time and your knowledge on this subject.

If you are worried that the speakers will be damaged can we assume you listen loud typically?
No, I don't actually. It will primarily be for TV/movie watching so fairly moderate volumes.

In short, I really wouldn't worry. You can never fully protect a domestic amplifier from abuse, but 99% of the time its just not an issue. Most damage occurs when people crank the volume to see what their system can do, so don't do this and just enjoy listening to it at a reasonable and comfortable volume :)
That is good to know. I don't intend testing out the limits of the system - I just have to keep the remote control away from my 4-year old (and the wife too possibly! :))

You don’t say what size your room is and what your expectation of the system is.
Apologies for not being clear. My lounge is about 6m x 4m - probably average for UK standards and small for US standards I'd imagine. I do intend moving country over the next few months and fairly certain my next place will be open plan, which I now realise might pose bit of an issue with the DX-2s :-( Unfortunately, I don't quite want to stretch to more expensive speakers at the moment so maybe there's more creative ways of getting the sound to "envelope" ?

this Denon should be able to play so loud that normal people (not you :D ) would most likely run out of room before nearing the limits.
That's the quickest someone has worked out I'm not normal :-D !

95w for 5channels driven 4ohm load
Thanks for digging that up. Realise it's for the 2600H but I'd imagine the 2700H would at least match that. That brings me back to my original concern though - the DX2's recommend 20-60W, so there seems like a real chance for some sort of damage even at moderate volumes?

I'm guessing this would have blown bookshelves, but then if I had bookshelves I wouldn't need such a powerful amp
Thanks for sharing that. That's sort of the thing I was worried about.


Many thanks again for everyone's input, I'm enjoying the learning.
 
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gadgetluvr

Active Member
at being the case in this instance maybe the OP could set the X2700 to 4 Ohm output and that will slash the amps output and thereby reduce any chance of his avr from providing too much power.

Of course apart from this the owner does have control of the volume control and also as previously suggested can set limits on volume from within the menu settings.

I'll investigate that option thanks, sounds like that might be the solution to making sure there's no inadvertent damage to the speakers if I do end up keeping them!
 

Gasp3621

Distinguished Member
No, I don't actually. It will primarily be for TV/movie watching so fairly moderate volumes

That brings me back to my original concern though - the DX2's recommend 20-60W, so there seems like a real chance for some sort of damage even at moderate volumes?

No there won´t be any issues with your use! I would keep the impedance switch always at 8ohm position, unless you are putting your receiver in a place where it doesn´t have enough ventilation getting very hot which can reduce the life of it. I thought you would be blasting them like @kbfern does usually. :laugh: People who usually ask these kind of things tend to go balls to walls.

Check crossover settings after Audussey run. I would assume ~120hz would be ideal for them and such small sealed speakers are best close to walls/wall mounted. The center channel was ported though if i remember correct so if you keep the port open leave some space behind and don´t place it inside cabinet. Read some basics about speaker placement especially if you wall mount them (tweeters at seated ear height - speakers not too close each other etc), the small sealed sub i would put front corner close to LCR as it has to play quite high and your room is bit on large side for it anyway. Follow the on-screen Audussey setup and you should be fine. Keeping the mic in close area, far away from any walls though, room totally silent etc. Use the cardboard stand for the mic. You can do the 3mic positions first..

Settings for the subwoofer (rear):

Connect to LFE/R (red)
Auto sense On
Phase to 0
Crossover knob to max (150hz)
Volume knob to 12clock
 

rccarguy

Active Member
Nope I wired up wharfedale diamond 9.0 to my ATI amp..200w into 8ohm 300w into 4ohm

No fires started
 

gadgetluvr

Active Member
No there won´t be any issues with your use! I would keep the impedance switch always at 8ohm position, unless you are putting your receiver in a place where it doesn´t have enough ventilation getting very hot which can reduce the life of it. I thought you would be blasting them like @kbfern does usually. :laugh: People who usually ask these kind of things tend to go balls to walls.

Check crossover settings after Audussey run. I would assume ~120hz would be ideal for them and such small sealed speakers are best close to walls/wall mounted. The center channel was ported though if i remember correct so if you keep the port open leave some space behind and don´t place it inside cabinet. Read some basics about speaker placement especially if you wall mount them (tweeters at seated ear height - speakers not too close each other etc), the small sealed sub i would put front corner close to LCR as it has to play quite high and your room is bit on large side for it anyway. Follow the on-screen Audussey setup and you should be fine. Keeping the mic in close area, far away from any walls though, room totally silent etc. Use the cardboard stand for the mic. You can do the 3mic positions first..

Settings for the subwoofer (rear):

Connect to LFE/R (red)
Auto sense On
Phase to 0
Crossover knob to max (150hz)
Volume knob to 12clock
Why do you suggest keeping the impedance setting at 8 ohm when Denon seems to suggest matching it to the speakers? There shouldn't be any ventilation issue btw where I will eventually place the AVR.

Thanks for the tips re speaker settings. Re crossover settings, you initially suggested 120 hz. but under "subwoofer settings" at the end you suggseted "max/150 hz." - what have I missed?
 

Gasp3621

Distinguished Member
Why do you suggest keeping the impedance setting at 8 ohm when Denon seems to suggest matching it to the speakers? There shouldn't be any ventilation issue btw where I will eventually place the AVR.

Thanks for the tips re speaker settings. Re crossover settings, you initially suggested 120 hz. but under "subwoofer settings" at the end you suggseted "max/150 hz." - what have I missed?

I meant 120hz from the receiver menu after Audussey assuming you don´t get any higher figures, then don´t lower them. For the sub you want to turn that knob to max always, it´s probably already bypassed when you connect to LFE. Receiver handles bass management.

As for the impedance switch, let´s take Denon X5200W measurements which is basically same as 6000 range these days, minus few channels.

Congratulations to Denon for making the world’s worst impedance selector switch of all time. With the low setting engaged, no matter how many channels were driven, the output was limited to about 25 watts/channel with one channel driven and significantly less with all channels driven (18 watts for seven channels driven). Denon jumped on the impedance switch bandwagon to get the UL 4 ohm rating, but severely choked off performance in doing so. This is likely due for two reasons, inadequate heat sink area to keep the receiver running cool enough for the rating, and an overzealous and cautious safety engineer that took things just a little too far. Regardless of whatever speaker impedance you have, under NO circumstance do I EVER recommend using the low impedance setting. Just leave it at the default 8 ohm setting and forget there is even an option to change it.

More here:
 

gadgetluvr

Active Member
I meant 120hz from the receiver menu after Audussey assuming you don´t get any higher figures, then don´t lower them. For the sub you want to turn that knob to max always, it´s probably already bypassed when you connect to LFE. Receiver handles bass management.

As for the impedance switch, let´s take Denon X5200W measurements which is basically same as 6000 range these days, minus few channels.

Congratulations to Denon for making the world’s worst impedance selector switch of all time. With the low setting engaged, no matter how many channels were driven, the output was limited to about 25 watts/channel with one channel driven and significantly less with all channels driven (18 watts for seven channels driven). Denon jumped on the impedance switch bandwagon to get the UL 4 ohm rating, but severely choked off performance in doing so. This is likely due for two reasons, inadequate heat sink area to keep the receiver running cool enough for the rating, and an overzealous and cautious safety engineer that took things just a little too far. Regardless of whatever speaker impedance you have, under NO circumstance do I EVER recommend using the low impedance setting. Just leave it at the default 8 ohm setting and forget there is even an option to change it.

More here:
aah I see, wasn't aware that the receiver would override the sub-settings, thanks will note that for when my 2700H eventually arrives!

That's crazy btw re what the Denon amps do get that 4 ohm rating! I'll call them up now and see if I can get any more info on what the 2700H does at that setting. It'll be ridiculous if it drops down to as low as 25W/channel. And that was a good article btw, thanks!
 
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Gasp3621

Distinguished Member
aah I see, wasn't aware that the receiver would override the sub-settings, thanks will note that for when my 2700H eventually arrives!

That's crazy btw re what the Denon amps do get that 4 ohm rating! I'll call them up now and see if I can get any more info on what the 2700H does at that setting. It'll be ridiculous if it drops down to as low as 25W/channel. And that was a good article btw, thanks!

It´s the same with other brands so no need to blame Denon. ECO mode "On" and impedance switch at 4ohm is two things you shouldn´t use generally. You get more power to lower impedance load if you keep it at 8ohm position so don´t worry about the silly switch. Make sure there is enough ventilation on top and sides, then you are good to go!
 

gadgetluvr

Active Member
It´s the same with other brands so no need to blame Denon. ECO mode "On" and impedance switch at 4ohm is two things you shouldn´t use generally. You get more power to lower impedance load if you keep it at 8ohm position so don´t worry about the silly switch. Make sure there is enough ventilation on top and sides, then you are good to go!
Will do, thanks! Amazing how many different variables are in play if you want to do this properly. I'm coming from an all-in-one Panasonic 5.1 system which, to be fair, wasn't too bad however I am hoping this will be a step up in terms of sound plus I needed more than the 2 HDMI inputs the Panasonic had.
 

The Dreamer

Distinguished Member
That is good to know. I don't intend testing out the limits of the system - I just have to keep the remote control away from my 4-year old (and the wife too possibly! :))

In the audio settings of your AVR, you can set a maximum volume, such that no matter what your kids and wife get up to (or you), you will never overdrive your speakers.

You find it by going to Audio->Volume->Limit.

Limit
Make a setting for maximum volume.​
60 – 80 (–20 dB – 0 dB)​
Off(Default)​

HTH
 

gadgetluvr

Active Member
In the audio settings of your AVR, you can set a maximum volume, such that no matter what your kids and wife get up to (or you), you will never overdrive your speakers.

You find it by going to Audio->Volume->Limit.

HTH
Thanks, that’s one of the first things I’d planned on doing.
 

SOUNDVISION

Active Member
Oh that's a relief, thank you! May I ask how you worked out the 60W/channel figure?

I'll also investigate the volume limits you have suggested. My understanding intially was you might not always hear the distortion if the amp was delivering too much power but you could still be damaging the speaker elements.
Most AV Receiver Manufacturers exaggerate the truth, it is never going to be what they say of100 watt per channel, in real power terms realistically you will get 60 watt per channel if that, that's why a lot of people buy power amps to give more power to the speakers because AV Receivers are not giving enough.
Especially for 2ch music, AV Receivers always come short of power compared to a Stereo Amp that has more power per channel
 

gadgetluvr

Active Member
Most AV Receiver Manufacturers exaggerate the truth, it is never going to be what they say of100 watt per channel, in real power terms realistically you will get 60 watt per channel if that, that's why a lot of people buy power amps to give more power to the speakers because AV Receivers are not giving enough.
Especially for 2ch music, AV Receivers always come short of power compared to a Stereo Amp that has more power per channel
Not sure why they wouldn't put more realistic figures across multiple channels (other than headline grabbing power figures), I mean it's highly unlikely anyone would buy an amp like this and connect just the one channel! I've spent over 2 hours on hold to Denon (thank God for speaker phone!) over 2 calls before giving up - I just wanted to ask them continuous power figures in 5.1.2 mode. Really hope I don't need to call them for any technical issues if this is the level of service that their sales option gives!
 

Gasp3621

Distinguished Member
Not sure why they wouldn't put more realistic figures across multiple channels (other than headline grabbing power figures), I mean it's highly unlikely anyone would buy an amp like this and connect just the one channel! I've spent over 2 hours on hold to Denon (thank God for speaker phone!) over 2 calls before giving up - I just wanted to ask them continuous power figures in 5.1.2 mode. Really hope I don't need to call them for any technical issues if this is the level of service that their sales option gives!

It wouldn´t sell as good if there is 7x60w as they can market 1ch figure with high THD around 150-200w so person who see this sticker will jump on it. For normal person he doesn´t understand that the 7x60w spec can be more than he ever needs. Also the all channels driven (ACD) test figures won´t really translate that good for real world program material. You aren´t powering the speakers full range, subwoofer(s) with own amp is taking big load off. All speakers won´t be drawing power continuosly, only very short times. Speaker choice is also critical, larger more efficient speakers with higher sensitivity helps big time. Look some of the pro cinema spekers, you can run them to ear bleeding levels with budget receiver.

" While some enthusiasts may rightly want All Channels Driven (ACD) tests all the time, it’s often impractical and not a real world test condition since there is never any time when real program material will require full-bandwidth power from ACD simultaneously. - Audioholics "




10% THD spec = useless, but sells better!



Big figure printed in red to sell, printed in small the real 2ch spec (80w).

Here is more if you want to read the whole article:
 

rccarguy

Active Member
Most AV Receiver Manufacturers exaggerate the truth, it is never going to be what they say of100 watt per channel, in real power terms realistically you will get 60 watt per channel if that, that's why a lot of people buy power amps to give more power to the speakers because AV Receivers are not giving enough.
Especially for 2ch music, AV Receivers always come short of power compared to a Stereo Amp that has more power per channel

Avr amps can provide enough power in 2ch mode, I think bottom of the range
Not sure why they wouldn't put more realistic figures across multiple channels (other than headline grabbing power figures), I mean it's highly unlikely anyone would buy an amp like this and connect just the one channel! I've spent over 2 hours on hold to Denon (thank God for speaker phone!) over 2 calls before giving up - I just wanted to ask them continuous power figures in 5.1.2 mode. Really hope I don't need to call them for any technical issues if this is the level of service that their sales option gives!

Just buy power amps and never look back. I have 2.1kW on tap and that's all channels driven full range 0.05%thd
 

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