Ascend Sierra Tower + Emotiva XPA-11 = Burnt Voicecoil

[jeeper]

Hi all - long time follower, but first time posting here... I have my HT setup with a Marantz AV7705, Emotiva XPA-11, and a bunch of speakers from Ascend Acoustics (front/surrounds) and RSL for Atmos.

The front L/R are the Ascend Sierra Towers, and Center is a Sierra Horizon. These are connected to the mono-blocks of the amp.

I was recently playing some music in stereo mode, not that loud (-8, -6 db tops), and turns out that I busted my midrange woofers. There was the distinct smell of burned rubber, and it the midrange from both towers were done. One completely gave out (no sound at all), while the other was distorted.

Contacted Ascend, and they were super nice and helped me get replacement woofers. They thought the amp was not powerful enough and probably clipped. I don't see how that might be the case...

Tested the amp with some other speakers, and there's no hum or pops when on, playing music, or when switching on/off.

Any thoughts on these corridors of knowledge what the issue might be? I just don't want this happening again...


Thanks in advance!
Jeeper

 

[Replicant 7]

-6db is very high, than factor in dynamic headroom your more than likely hitting +1 or more.

 

[jeeper]

-6db is very high, than factor in dynamic headroom your more than likely hitting +1 or more.

Thanks for the reply. Just to make sure if we're on the same page regarding volume... When I say -6db, this is from the volume control on the Marantz... Not really sure how all these tie together technically

 

[M Code]

Level is 1 point but what about distortion...
Depending upon the source media, if compressed like an MP3 stream can have high distortion...
Sometimes distortion may not be that audible but still it can take out a loudspeaker driver..

Just my $0.02...

 

[Replicant 7]

Thanks for the reply. Just to make sure if we're on the same page regarding volume... When I say -6db, this is from the volume control on the Marantz... Not really sure how all these tie together technically

Yep, that's what was talking about the volume display on your AVR. But really a SPL meter would do nicely. I mean just how accurate the db volume display really is on AVR'S. How old are your speakers.

 

[ryanosaur]

Also, a point of note… what are your trim levels set at for your mains? If you boosted them in any way, by chance, that could push potential levels up much higher.

Likewise… if a source is mixed hot, like some YouTube content can be, further care must be taken.

 

[shadyJ]

Clipping distortion should kill the tweeter first rather than the woofer. The level of clipping needed to kill a modern loudspeaker driver is a lot, and I think you would have noticed it. Either the midrange on that speaker is relatively fragile, or you just got carried away with the volume and blew the speakers. The Emotive amp looks powerful enough to destroy the speakers without needing to be driven into clipping.

 

[slipperybidness]

Clipping distortion should kill the tweeter first rather than the woofer. The level of clipping needed to kill a modern loudspeaker driver is a lot, and I think you would have noticed it. Either the midrange on that speaker is relatively fragile, or you just got carried away with the volume and blew the speakers. The Emotive amp looks powerful enough to destroy the speakers without needing to be driven into clipping.

Does the integrated transformer for ribbon tweeters change that any? Or, it is irrelevant, and the tweeter remains the most susceptible to distortion?

 

[Replicant 7]

Level is 1 point but what about distortion...
Depending upon the source media, if compressed like an MP3 stream can have high distortion...
Sometimes distortion may not be that audible but still it can take out a loudspeaker driver..

Just my $0.02...

There you are @M Code! Andrew and I where just talking about you the other day. We both where wondering. I use a meter or I should say use to when I'd jack the volume up high. I'd never let it get much passed 95db.

 

[jeeper]

Level is 1 point but what about distortion...

Depending upon the source media, if compressed like an MP3 stream can have high distortion...

Sometimes distortion may not be that audible but still it can take out a loudspeaker driver..


Just my $0.02...

Source was Tidal when this happenned... so no concerns regarding source.

Also, a point of note… what are your trim levels set at for your mains? If you boosted them in any way, by chance, that could push potential levels up much higher.


Likewise… if a source is mixed hot, like some YouTube content can be, further care must be taken.

No boosts. For music the adjustments was set at zero db.

 

[shadyJ]

Does the integrated transformer for ribbon tweeters change that any? Or, it is irrelevant, and the tweeter remains the most susceptible to distortion?

I don't know. I would guess that the measures needed to be taken to protect the tweeter would have to be done in the crossover circuit.

 

[M Code]

Source was Tidal when this happenned... so no concerns regarding source.

Just because the Tidal stream is not compressed...
But still doesn't confirm the stream doesn't have high distortion, and for some music tracks the distortion may not be as audible...

Just my $0.02...

 

[PENG]

Thanks for the reply. Just to make sure if we're on the same page regarding volume... When I say -6db, this is from the volume control on the Marantz... Not really sure how all these tie together technically

You can't just go by the volume setting. The bottom line is if the input level is high enough, even -10 or lower on the master volume can blow your speakers. The input level depends on the source contents, some may be recorded at higher level than normal, and may be compressed so you could be listening at high enough level for long enough to cook the voice coils. If it was clipping that killed it, you would heard the distortion and turned down the volume naturally.

So what kind of media contents and what was the media player used, network streaming (external dac and Foobar/JRiver, CD/BR players etc.) you were playing at the time?

Edit: I missed that it was Tidal.

 

[lovinthehd]

Just because the Tidal stream is not compressed...
But still doesn't confirm the stream doesn't have high distortion, and for some music tracks the distortion may not be as audible...

Just my $0.02...

You have some information on this compressed streams having high distortion? That's something I haven't seen particularly....

 

[lovinthehd]

FWIW I have some audio sources that run at higher levels than others...while a movie at -6 can be quite loud, the bets are off if that same volume level is used if you're playing music with a source with a higher signal level...I've used inbuilt streaming services in an avr that yield very high levels, much higher than other sources....(sometimes I even trim those down with the input level adjustment). I more would expect the tweeters to blow, tho. Did Ascend (Dave F particularly) comment further after you advised them what specific setup you were using?

 

[davidscott]

I used to have problems with my Polk model 7Bs back in the 80s. Blew one or both of the tweeters at least twice. Funny I never had that problem with my New Large Advents, Allison Sixes, DCM Time Widows, or my current Infinity Primus. Man, I loved the sound of those Polks but they seemed to always be in the shop being repaired.

 

[TLS Guy]

Hi all - long time follower, but first time posting here... I have my HT setup with a Marantz AV7705, Emotiva XPA-11, and a bunch of speakers from Ascend Acoustics (front/surrounds) and RSL for Atmos.

The front L/R are the Ascend Sierra Towers, and Center is a Sierra Horizon. These are connected to the mono-blocks of the amp.

I was recently playing some music in stereo mode, not that loud (-8, -6 db tops), and turns out that I busted my midrange woofers. There was the distinct smell of burned rubber, and it the midrange from both towers were done. One completely gave out (no sound at all), while the other was distorted.

Contacted Ascend, and they were super nice and helped me get replacement woofers. They thought the amp was not powerful enough and probably clipped. I don't see how that might be the case...

Tested the amp with some other speakers, and there's no hum or pops when on, playing music, or when switching on/off.

Any thoughts on these corridors of knowledge what the issue might be? I just don't want this happening again...


Thanks in advance!
Jeeper

I can tell what happened. That Emotiva amp fried those speakers from DC offset. Emotiva gear is junk, pure and simple. Obviously that amp is not properly protected from DC offset. Get rid of that amp now, unless you want to keep replacing woofer drivers.

There is never a cap in series with a woofer or mid woofer. Midranges and tweeters always have at least one cap in series with the drivers as part of the crossover. Caps will not pass DC. The clincher here is that the tweeters are OK, which are the most sensitive drivers to overdriving.

You have a power transistor which is failing and passing the DC rail voltage to the mid-woofers, when it gets to a certain temperature point. This will get rapidly worse and cause you a lot of grief.

In the early days back in the seventies, when direct coupled output stages first appeared, this became a problem. I got stung twice. It then became apparent that protection was required for DC offset. There are various ways of doing this. The best, which is used in many amps now, is optocoupler protection.

 

[PENG]

I can tell what happened. That Emotiva amp fried those speakers from DC offset. Emotiva gear is junk, pure and simple. Obviously that amp is not properly protected from DC offset. Get rid of that amp now, unless you want to keep replacing woofer drivers.

There is never a cap in series with a woofer or mid woofer. Midranges and tweeters always have at least one cap in series with the drivers as part of the crossover. Caps will not pass DC. The clincher here is that the tweeters are OK, which are the most sensitive drivers to overdriving.

You have a power transistor which is failing and passing the DC rail voltage to the mid-woofers, when it gets to a certain temperature point. This will get rapidly worse and cause you a lot of grief.

In the early days back in the seventies, when direct coupled output stages first appeared, this became a problem. I got stung twice. It then became apparent that protection was required for DC offset. There are various ways of doing this. The best, which is used in many amps now, is optocoupler protection.

It isn't hard to find out if dc is the culprit, until then I would consider it just a possibility, but I wouldn't be so sure that it is.

I won't buy an Emo amp myself though I doubt they are as bad as you say they are.

 

[Pogre]

I own the Sierra towers and Horizon too. I've had them very loud, 0 on my dial, and didn't have any troubles. I didn't play it that loud for more than a song or 2, but I measured north of 100 dB peaks at my seat 14' away. It was very loud. Uncomfortably loud, lol.

Long story short, they can handle a lot of unclipped power in my experience. My amp is capable of 300 wpc into 4 ohms. I can't imagine what it'd take to blow that midrange driver, but I'd expect the tweet to go first if it was clipping.

 

[Pogre]

I can tell what happened. That Emotiva amp fried those speakers from DC offset. Emotiva gear is junk, pure and simple. Obviously that amp is not properly protected from DC offset. Get rid of that amp now, unless you want to keep replacing woofer drivers.

There is never a cap in series with a woofer or mid woofer. Midranges and tweeters always have at least one cap in series with the drivers as part of the crossover. Caps will not pass DC. The clincher here is that the tweeters are OK, which are the most sensitive drivers to overdriving.

You have a power transistor which is failing and passing the DC rail voltage to the mid-woofers, when it gets to a certain temperature point. This will get rapidly worse and cause you a lot of grief.

In the early days back in the seventies, when direct coupled output stages first appeared, this became a problem. I got stung twice. It then became apparent that protection was required for DC offset. There are various ways of doing this. The best, which is used in many amps now, is optocoupler protection.

I don't know if this would be a factor, but they do have the midrange in its own sealed compartment and tuned to roll off naturally to the bass drivers.