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"Official" Audyssey thread (FAQ in post #51779) - Page 1975

post #59221 of 70896
Guys,

Let's forget about subwoofer trim settings for the time being and concentrate on this example:

You have a very large room with very low efficiency speakers. Audyssey sets the trims of each speaker to the upper range like +9-11 dB. The speakers don't have a gain control.

Whats the next step? Will you tear yourself apart for risking damage to your speakers or you will just call it a day and move on?
post #59222 of 70896
Quote:
Originally Posted by mogorf View Post

Guys,

Let's forget about subwoofer trim settings for the time being and concentrate on this example:

You have a very large room with very low efficiency speakers. Audyssey sets the trims of each speaker to the upper range like +9-11 dB. The speakers don't have a gain control.

Whats the next step? Will you tear yourself apart for risking damage to your speakers or you will just call it a day and move on?
In this example, if:
A) your speakers have low sensitivity
and
B) your amps have no gain setting/adjustment

I personally would (and did) use measuring equipment to measure for compression/distortion to the maximum SPL desired at the MLP. I measured my 89db/w/m Boston Acoustics E100's at the MLP with full range sweeps at 75db, then 85db, 95db and finally 105db and compared all the traces. In my room at 10', the traces were identical with the XPA-1's. From calculations though, I realized that I was approaching the rated power handling limits of the E100's (400watts @ 8ohms), to hit THX Reference at 10', and I'd planned on moving the setup to a bigger HT, so I ended up with Legacy Audio Focus SE's rated at ~95db/w/m @ 4ohms with a rated power handling of 500 watts (with the XPA-1's capable of pushing 1000watts @ 4ohms with minimal distortion), giving me the headroom I desired.

IF the setup in your example proved capable of reproducing the desired max SPL without distortion, then all's well and good. If the system showed distortion, I would determine the cause of the distortion, i.e. is the system distorting because the amp is underpowered? Because the speakers cannot physically produce the required SPL? Because the amp's input cannot handle the maximum output range of the avr?

Regardless of the cause and origin of the distortion there are only two viable options to me:
a) either play at lower volumes
or
b) upgrade as necessary to achieve the desired goal.


Max
post #59223 of 70896
Quote:
Originally Posted by djbluemax1 View Post

In this example, if:
A) your speakers have low sensitivity
and
B) your amps have no gain setting/adjustment

I personally would (and did) use measuring equipment to measure for compression/distortion to the maximum SPL desired at the MLP. I measured my 89db/w/m Boston Acoustics E100's at the MLP with full range sweeps at 75db, then 85db, 95db and finally 105db and compared all the traces. In my room at 10', the traces were identical with the XPA-1's. From calculations though, I realized that I was approaching the rated power handling limits of the E100's (400watts @ 8ohms), to hit THX Reference at 10', and I'd planned on moving the setup to a bigger HT, so I ended up with Legacy Audio Focus SE's rated at ~95db/w/m @ 4ohms with a rated power handling of 500 watts (with the XPA-1's capable of pushing 1000watts @ 4ohms with minimal distortion), giving me the headroom I desired.

IF the setup in your example proved capable of reproducing the desired max SPL without distortion, then all's well and good. If the system showed distortion, I would determine the cause of the distortion, i.e. is the system distorting because the amp is underpowered? Because the speakers cannot physically produce the required SPL? Because the amp's input cannot handle the maximum output range of the avr?

Regardless of the cause and origin of the distortion there are only two viable options to me:
a) either play at lower volumes
or
b) upgrade as necessary to achieve the desired goal.


Max

Thanks for your input Max. But in case of average Joe who doesn't have such sophisticated measuring gear accopmanied will such high level of skills to use it, will most probably think this way.

My system seems OK, becasue each speaker channel trim came out within the upper limit of +12 dB, i.e. around 9 - 11 dB, so the trims did not max. out. Average Joe will ask himself: am I at risk for damaging my speakers or I'm good to go. In my opinion Joe is good to go and should worry not for blowing out any of his speakers! smile.gif

Should he experience distortion as he approaches 0 dB ref. level when he cranks up MV he should follow your way for determining problems. But nothing is there to look around at the trim settings, right?
Edited by mogorf - 1/20/13 at 4:24am
post #59224 of 70896
Quote:
Originally Posted by pepar View Post

I don't think there has been any disagreement over whether or not clipping can damage speakers.

Mogorf posted this: "Keith my friend, clipping of a sinusoidal signal means it's being transformed into a square wave. Feed this into a speaker and the speaker will play it. It will sound distorted, but the speaker does not care, it just plays what is fed into it. Feed a speaker with a distorted signal or a pure signal makes no difference for the speaker. You can't distroy a speaker with a clipped signal because the peak-to-peak voltage does not change. A speaker can only be destroyed by mechanical or thermal overload. A clipped signal will cause neither of these two cases."

Feri also posted a message saying that clipped signals don't destroy speakers.

That looks like disagreement with other posts (no need to quote them, they are numerous) stating that clipping does desteroy speakers.
post #59225 of 70896
Quote:
Originally Posted by djoberg View Post

Can you imagine what a thrill it was to actually hear (before I even read the results) that the sub was working during the calibration? tongue.gif I had the volume (this is an OLD sub and they didn't call it gain back then) set to 11 o'clock and the trim level read -9dB (I've never been so happy to see a minus sign cool.gif). Now I need to turn the sub volume down a bit more so I can get the trim level closer to the "safest range" (should we call it that, instead of the "ideal range"?), so I'm thinking I'll try the 9 o'clock level on the Velodyne.

 

What combination of gear is this with? Is this the Onk and the Velo? If so, then clearly the problem lies with the SVS sub.

post #59226 of 70896
Quote:
Originally Posted by pbarach View Post

Mogorf posted this: "Keith my friend, clipping of a sinusoidal signal means it's being transformed into a square wave. Feed this into a speaker and the speaker will play it. It will sound distorted, but the speaker does not care, it just plays what is fed into it. Feed a speaker with a distorted signal or a pure signal makes no difference for the speaker. You can't distroy a speaker with a clipped signal because the peak-to-peak voltage does not change. A speaker can only be destroyed by mechanical or thermal overload. A clipped signal will cause neither of these two cases."

Feri also posted a message saying that clipped signals don't destroy speakers.

That looks like disagreement with other posts (no need to quote them, they are numerous) stating that clipping does desteroy speakers.

Perhaps we'll have to agree to disagree as I am quite certain clipping can destroy tweeter in a speaker system with passive crossovers.
post #59227 of 70896
Quote:
Originally Posted by Tasdom View Post

i know this has been beat to death but based on my system, what would be the optimal starting crossovers for this set up:

Klipsch RF-7II Mains FREQUENCY RESPONSE: 30Hz-24KHz ± 3dB
Klipsch RC-64II Center FREQUENCY RESPONSE: 59Hz-24KHz ± 3dB
Klipsch RS-52II Surrounds FREQUENCY RESPONSE: 58Hz-24KHz ± 3dB
Klipsch RW-12D Subs x 2 FREQUENCY RESPONSE: 24-120Hz +/-3dB
Onkyo PR-SC5508 Pre/Pro
Emotiva XPA-5

Audyssey set everything to 40hz after calibration. I can apply individual settings to each speaker if they need not be uniform to all.

Thanks for any input!

 

See if these FAQ answers help:

 

c)2.   Why do I often see advice to raise the Crossovers to 80Hz?


c)3.   I have big tower speakers at the front. Shouldn't I set these to Large'?


c)4.   Is it OK to change the Crossovers from Audyssey's recommendation?

post #59228 of 70896
Quote:
Originally Posted by p3Orion View Post

Quote:
Originally Posted by kbarnes701 View Post

Both will do the job but the boom stand is so much easier to use it's worth the 20 bucks it costs. Repays you time and again in time saved.

d)1.   Do I really need to put the Audyssey mic on a tripod or stand?

I purchased the items recommended in this thread: On Stage Stands MS7701 Tripod Boom Microphone Stand and On Stage CM01 Video Camera/Digital Recorder Adapter. Thanks to whomever for the links.

I had reservations about getting a boom mic stand since I didn't know what else I would use it for. I sell items on ebay from time to time and have wanted to get a tripod to make taking pictures easier for quite a while. Can a digital camera be attached to the adapter and boom mic stand?

 

Yes - the thread on the Audyssey mic is a standard tripod thread. But the mic stand won’t give you anything like the stability of a tripod for photography. It amy be OK indoors and with a lightweight compact camera, but don't even think of putting an SLR on it.

post #59229 of 70896
Quote:
Originally Posted by mogorf View Post

Guys,

Let's forget about subwoofer trim settings for the time being and concentrate on this example:

You have a very large room with very low efficiency speakers. Audyssey sets the trims of each speaker to the upper range like +9-11 dB. The speakers don't have a gain control.

Whats the next step? Will you tear yourself apart for risking damage to your speakers or you will just call it a day and move on?

 

No - the speakers don't have amps inside them, so it will be impossible to clip the inputs as there, er, aren't any. Oranges and apples, Feri.

 

Good try at getting out of being wrong though - 'forgetting' the discussion and changing it to another discussion entirely wink.gif


Edited by kbarnes701 - 1/20/13 at 4:55am
post #59230 of 70896
Quote:
Originally Posted by mogorf View Post

 
My system seems OK, becasue each speaker channel trim came out within the upper limit of +12 dB, i.e. around 9 - 11 dB, so the trims did not max. out. Average Joe will ask himself: am I at risk for damaging my speakers or I'm good to go. In my opinion Joe is good to go and should worry not for blowing out any of his speakers! smile.gif
 

 

 

You don't have active speakers, with amps in them, IIRC. So this example is irrelevant to the discussion about clipping the amp input on an active speaker (eg a sub). If your speakers were active designs, the answer is the same as it has been before. So yes, in this irrelevant example, Joe is good to go. There is a FAQ section devoted to what happens if the trims max out on the main/surround channels - it is a separate topic to the one under discussion.

 

e)6.   What do I do if my trim levels are at the limits of their adjustment ('maxed out')?

 

 

post #59231 of 70896
Quote:
Originally Posted by Theresa View Post

Quote:
Originally Posted by pbarach View Post

Mogorf posted this: "Keith my friend, clipping of a sinusoidal signal means it's being transformed into a square wave. Feed this into a speaker and the speaker will play it. It will sound distorted, but the speaker does not care, it just plays what is fed into it. Feed a speaker with a distorted signal or a pure signal makes no difference for the speaker. You can't distroy a speaker with a clipped signal because the peak-to-peak voltage does not change. A speaker can only be destroyed by mechanical or thermal overload. A clipped signal will cause neither of these two cases."

Feri also posted a message saying that clipped signals don't destroy speakers.

That looks like disagreement with other posts (no need to quote them, they are numerous) stating that clipping does desteroy speakers.

Perhaps we'll have to agree to disagree as I am quite certain clipping can destroy tweeter in a speaker system with passive crossovers.

 

Everyone is certain, Theresa - except Feri! 

post #59232 of 70896
Quote:
Originally Posted by kbarnes701 View Post


Everyone has active speakers Keith!!!!!!!!!!!!!! Whaddaya think the amps in the AVR are for? Care to take a break before posting again? smile.gif
post #59233 of 70896
I intend to get around to re-running Audyssey today. I had to replace my right tweeter as the old one was intermittent and also moved my speakers a bit.
Back to weather, its zero degrees F. (-18 C) right now and this is supposed to be close to being the high. Its supposed to be even colder tomorrow. My multi-amp setup will be useful for heating my condo.
Edited by Theresa - 1/20/13 at 5:12am
post #59234 of 70896
Quote:
Originally Posted by pbarach View Post

Mogorf posted this: "Keith my friend, clipping of a sinusoidal signal means it's being transformed into a square wave. Feed this into a speaker and the speaker will play it. It will sound distorted, but the speaker does not care, it just plays what is fed into it. Feed a speaker with a distorted signal or a pure signal makes no difference for the speaker. You can't distroy a speaker with a clipped signal because the peak-to-peak voltage does not change. A speaker can only be destroyed by mechanical or thermal overload. A clipped signal will cause neither of these two cases."

Feri also posted a message saying that clipped signals don't destroy speakers.

That looks like disagreement with other posts (no need to quote them, they are numerous) stating that clipping does desteroy speakers.

Believe it or not, you can destroy a speaker even with one pure and genuine sine wave!! How?

Hook up a high power amp with low power rated speakers, crank up the volume and wait for the smoke!! For the fun of it connect your subwoofer to a nuclear power plant. What will you hear? 50 or 60 Hz, well..for a fraction of a moment surely! And then comes the smoke! OK, kidding aside.

Let's look at a sine wave and a square wave. A sine wave contains only one frequency. Transform it into a square wave and apart from that one sine wave as a fundamental an ideal (repeat: ideal) square wave will contain an infinite number of frequencies above the fundamental (not limited to harmonics only).

Let's translate this into our world. Playing a square wave will simulate a full band playback. Just like playing real world program materials (film or music). As long as the peal-to-peak voltage value of the sq wave and the sine wave are the same, there is no risk of damaging your speaker.
post #59235 of 70896
Quote:
Originally Posted by mogorf View Post

Quote:
Originally Posted by kbarnes701 View Post
 

Everyone has active speakers Keith!!!!!!!!!!!!!! Whaddaya think the amps in the AVR are for? Care to take a break before posting again? smile.gif

 

Now you are just being ridiculous, Feri. You know very well that 'active' speakers are speakers with internal amps and 'passive' speakers are driven by external amps. This latest attempt to change the subject by trying to shift the discussion to trim level setting on passive speakers is just unbelievable. 

 

Has someone hacked your AVS account?  I find it hard to believe this is really you posting. First you start a crusade to try to persuade everyone that there is some problem in setting trims to +/- 3.5dB, then you assert that clipping cannot destroy a speaker, now you say you don't know what an 'active' speaker is.... I find it hard to believe.

 

For the record, this is what I said that prompted the ludicrous response above:

 

"You don't have active speakers, with amps in them, IIRC." (My bolding)

post #59236 of 70896
Quote:
Originally Posted by kbarnes701 View Post

Now you are just being ridiculous, Feri. You know very well that 'active' speakers are speakers with internal amps and 'passive' speakers are driven by external amps. This latest attempt to change the subject by trying to shift the discussion to trim level setting on passive speakers is just unbelievable. 

Has someone hacked your AVS account?  I find it hard to believe this is really you posting. First you start a crusade to try to persuade everyone that there is some problem in setting trims to +/- 3.5dB, then you assert that clipping cannot destroy a speaker, now you say you don't know what an 'active' speaker is.... I find it hard to believe.

Every speaker in a HT system is hooked up to an amplifier. Whether they are in the same box or not it doesn't matter. AVR's typically only have power amps on-board for the satellites, while the sub only has line out.

Glad to could learn something new from me! smile.gif
post #59237 of 70896
Its the harmonics generated by clipping that can destroy tweeters.
As for active speakers what I mean is pre-amp output to miniDSPs to amplifier inputs. One amp channel for every speaker driver. Clipping the midwoofers' amps results in no harmonics reaching the tweeters so they are immune to the above mentioned harmonics generated by clipping. Active crossover's/speaker's have several more important benefits.
post #59238 of 70896
Quote:
Originally Posted by kbarnes701 View Post

What combination of gear is this with? Is this the Onk and the Velo? If so, then clearly the problem lies with the SVS sub.

Yes, the Onkyo and Velodyne. Audyssey worked flawlessly with the Velodyne and I must say this sub has never sounded so good!

SVS is closed for the weekend but I've already emailed and called them, plus Jack is fully aware of the problem and suspected it was either the sub or AVR. I'm thinking they'll just send me a new amp.
post #59239 of 70896
Quote:
Originally Posted by Theresa View Post

I intend to get around to re-running Audyssey today. I had to replace my right tweeter as the old one was intermittent and also moved my speakers a bit.
Back to weather, its zero degrees F. (-18 C) right now and this is supposed to be close to being the high. Its supposed to be even colder tomorrow. My multi-amp setup will be useful for heating my condo.

It's -6F here in West Central Minnesota with an expected HIGH tomorrow of -13!!
post #59240 of 70896
Quote:
Originally Posted by Theresa View Post

Its the harmonics generated by clipping that can destroy tweeters.
As for active speakers what I mean is pre-amp output to miniDSPs to amplifier inputs. One amp channel for every speaker driver. Clipping the midwoofers' amps results in no harmonics reaching the tweeters so they are immune to the above mentioned harmonics generated by clipping. Active crossover's/speaker's have several more important benefits.

Theresa, why harmonics? What is the base frequency in that case?

Do you agree with me that even one sine wave can destroy any speaker not just the tweeter if the sine wave is powerful enough?
post #59241 of 70896
Quote:
Originally Posted by djoberg View Post

It's -6F here in West Central Minnesota with an expected HIGH tomorrow of -13!!

I'm originally from Sauk Centre so I'm familiar with the area. Its not supposed to be as cold as where you are here in the Twin Cities, thank goodness.
post #59242 of 70896
Quote:
Originally Posted by Theresa View Post

I intend to get around to re-running Audyssey today. I had to replace my right tweeter as the old one was intermittent and also moved my speakers a bit.
Back to weather, its zero degrees F. (-18 C) right now and this is supposed to be close to being the high. Its supposed to be even colder tomorrow. My multi-amp setup will be useful for heating my condo.

Quote:
Originally Posted by djoberg View Post

It's -6F here in West Central Minnesota with an expected HIGH tomorrow of -13!!

yea well it's a balmy 8 degress here now...so ha ha i'm in paradise.biggrin.gif
post #59243 of 70896
Quote:
Originally Posted by mogorf View Post

Quote:
Originally Posted by kbarnes701 View Post

Now you are just being ridiculous, Feri. You know very well that 'active' speakers are speakers with internal amps and 'passive' speakers are driven by external amps. This latest attempt to change the subject by trying to shift the discussion to trim level setting on passive speakers is just unbelievable. 

Has someone hacked your AVS account?  I find it hard to believe this is really you posting. First you start a crusade to try to persuade everyone that there is some problem in setting trims to +/- 3.5dB, then you assert that clipping cannot destroy a speaker, now you say you don't know what an 'active' speaker is.... I find it hard to believe.

Every speaker in a HT system is hooked up to an amplifier. Whether they are in the same box or not it doesn't matter. AVR's typically only have power amps on-board for the satellites, while the sub only has line out.

Glad to could learn something new from me! smile.gif

 

Feri, I honestly think something is wrong. Or it isn’t you. 

 

I suggest you research active (ie powered) speakers before we go any further. If you genuinely don't know the difference between active and passive speakers and the benefits of the former, there is no way to continue this meaningfully.

post #59244 of 70896
Quote:
Originally Posted by djoberg View Post

Quote:
Originally Posted by kbarnes701 View Post

What combination of gear is this with? Is this the Onk and the Velo? If so, then clearly the problem lies with the SVS sub.

Yes, the Onkyo and Velodyne. Audyssey worked flawlessly with the Velodyne and I must say this sub has never sounded so good!

SVS is closed for the weekend but I've already emailed and called them, plus Jack is fully aware of the problem and suspected it was either the sub or AVR. I'm thinking they'll just send me a new amp.

 

Yes - a new amp for the sub would be an easy test/fix. Thank god it's SVS you are having to deal with and not Onkyo! :)

post #59245 of 70896
Quote:
Originally Posted by djoberg View Post

It's -6F here in West Central Minnesota with an expected HIGH tomorrow of -13!!
.

Wow, that is hard for me believe. It will be 70 degrees F here today.
post #59246 of 70896
Quote:
Originally Posted by mogorf View Post

Every speaker in a HT system is hooked up to an amplifier. Whether they are in the same box or not it doesn't matter. AVR's typically only have power amps on-board for the satellites, while the sub only has line out.

Glad to could learn something new from me! smile.gif

Are you really trying to redefine the terms "active" and "passive" regarding speakers? This is getting more than a little ridiculous.
post #59247 of 70896
posts deleted
post #59248 of 70896
Quote:
Originally Posted by Theresa View Post

Its the harmonics generated by clipping that can destroy tweeters.

I did not know that. I thought a clipped sine wave was essentially DC and that that was what overheated the voicecoil causing windings to lift into the gap and/or burn out?
Edited by pepar - 1/20/13 at 8:27am
post #59249 of 70896
What matters is the total power being delivered to the speaker driver. When an amplifier clips, it's usually because its input signal voltage is so large that the amp is delivering its maximum possible power long before and after the input signal gets to its peak. I wouldn't expect square waves at very small signal levels to cause problems in most cases.

One can describe a clipped signal (or square wave) as the sum of a large number of sine waves of varying amplitudes and frequencies. (That's called Fourier analysis.) When compared to a pure sine wave at the same frequency as the square wave, the square wave contains many additional high-amplitude, high-frequency sine waves. Saying that those high frequencies damage speaker drivers is just another way of describing the same situation. People often forget to mention that it's their amplitudes which matter, though.
post #59250 of 70896
Is it true that most blown speakers are due to clipping of inadequate amplifiers than from too much undistorted power being delivered to them? That has always been my belief.

When I listen to hi-res multichannel music at high volumes - and it seems easier to do that because it is so clean - some material causes clipping. My ears tell me it is my amp beginning to clip, and this causes me to consider bigger amps.

Jeff
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