Protection Mode issue

[ramirezz]

Hi

I run a 7.4.2 system with a denon 4700 running as pre-amp (in pre amp mode). I used to power my speaker with a XPA-9 and some other random amp without any issues.

I recently bought a XPA-DR2 and a XPA-DR3 to upgrade the sound of my front and suround speakers. They are rather large towers (excempt the center) from Nubert (Nuvero Series), see: www.nubert.de/nuvero-serie/510/ . The Denon Pre-Amp is connected to the DR2 and DR3 using this cables (all new cables): Mogami 2534 Quad Stereo Paar, Cinch RCA - XLR male. 

Now I run into issues, which have not been there before. The DR3 amp goes into protection mode in (very) loud movie scence. I believe to have played same scence with the XPA-9, never ever going into protection mode. The issue is perfectly reproducable for the same scene in the same volume (the amp always goes into protection mode in the exact same point in times). I tried to swap the DR3 and the DR2, however, also the DR2 goes into protection mode in the exact same point in time. Any idea what could cause this? As said, the XPA-9 never did this, only the DR2 and DR3 are doing it. The scence are loud, but not defening loud. Lots of base, certainly.

Help would be highly appreciated.

[KeithL]

It's possible that you're exceeding the power capabilities of your speakers.

Our amps will go into protect if they see something like a badly clipped signal or a bad cable connection.

However they will also go into protect if they detect certain bad things happening with the speaker itself.

For example, if you you overdrive some speakers badly, and drive the speaker's voice coil out of the magnet gap, or bounce the driver off the end stops...

This can cause a sudden "jump" in the speaker's impedance which the amplifier may see as a "load fault" - and treat the same way as a shorted or open cable...

(Really excessive bass levels, or a very powerful but very short transient, can cause this to happen.)

(It could also suggest that a part in the speaker is failing - but that is unlikely.)

The fact that both amps do this, and that it happens at the exact same spot, suggests that this is what's happening...

(And odds are that the XPA-9 simply wasn't powerful enough to cause the speaker itself to misbehave.)

You may just have to turn the volume down a little bit...

Nov 4, 2021 10:31:21 GMT -5 ramirezz said:

Hi

I run a 7.4.2 system with a denon 4700 running as pre-amp (in pre amp mode). I used to power my speaker with a XPA-9 and some other random amp without any issues.

I recently bought a XPA-DR2 and a XPA-DR3 to upgrade the sound of my front and suround speakers. They are rather large towers (excempt the center) from Nubert (Nuvero Series), see: www.nubert.de/nuvero-serie/510/ . The Denon Pre-Amp is connected to the DR2 and DR3 using this cables (all new cables): Mogami 2534 Quad Stereo Paar, Cinch RCA - XLR male. 

Now I run into issues, which have not been there before. The DR3 amp goes into protection mode in (very) loud movie scence. I believe to have played same scence with the XPA-9, never ever going into protection mode. The issue is perfectly reproducable for the same scene in the same volume (the amp always goes into protection mode in the exact same point in times). I tried to swap the DR3 and the DR2, however, also the DR2 goes into protection mode in the exact same point in time. Any idea what could cause this? As said, the XPA-9 never did this, only the DR2 and DR3 are doing it. The scence are loud, but not defening loud. Lots of base, certainly.

Help would be highly appreciated.

[leonski]

I just looked at the Nuvero 60 speaker.

2 things jUMP out

First? VERY low sensitivity. 83db 1 watt and 86db @2.83volts

Second? Together with the first, above, they are 4ohm speakers....nominal.

Multiple speakers of this type will require a 'better than average' amp to get the most out of 'em......

Other specs listed but my German is a LITTLE Rusty.....!

[ramirezz]

Hi leonski and @keithl for the reply. Highly appreciated!

I do not have lots of experience in this area, but very much willing to learn a long the way. Big part of the fun for me. So:

-> First? VERY low sensitivity. 83db 1 watt and 86db @2.83volts

Yeah, That is what I picked up as well. I do understand the 83db 1 watt, and further math behind it, when the room gets bigger / the sound gets louder. Howeer, Whats the story with the 86db @2.83 how does that get into play with amplifiers?

-> Together with the first, above, they are 4ohm speakers....nominal.

Yes, however, similar to emotiva with the X Watt per Channel, they make a strong claim, that their speaker are really delivering on the 4ohm's claimed (other than many 8ohm speaker). However, could this pose an issue here?

-> Multiple speakers of this type will require a 'better than average' amp to get the most out of 'em......

Yes, that is what I was suspecting. Therefore I got the sdr2 (to drive two nuvero 110) and an sdr3 (to drive the nuvero 60 and two 140). What means "Better than average"? Can sdr2 / sdr3 be considered "above average"? I am aware that in the hifi community "above average" can be very much subject to be debated. For me some random Sonos speaker is "above average" ;-).

-> Other specs listed but my German is a LITTLE Rusty.....!

What else could be important? I could happily translate. Maybe also the nominal power handling (DIN EN 60268-5, 300 h), which is at 440W for the 140 and 280W for the 60.

-> You may just have to turn the volume down a little bit...

Could be it. But I believe that I was able to play them louder with the XPA9 without ever going into protection mode (did not measure it though). Is it possible, that the sdr2/sdr3 is stricter, and quicker goes to protection mode? Could there also be something wrong with the speaker cables (I replace one one adding the new amps)? Is it possible that the sdr3 throws more watt into the speaker, without them playing louder?

Maybe some of the questions are stupid, if so, I do hope for lenience ;-)

Further I just noted, that I put my post into the legacy amp part of the forum. I guess this is not really correct. sry, for that. Maybe this can be moved.

[leonski]

Nov 4, 2021 16:40:55 GMT -5 ramirezz said:

Hi leonski and @keithl for the reply. Highly appreciated!

I do not have lots of experience in this area, but very much willing to learn a long the way. Big part of the fun for me. So:

-> First? VERY low sensitivity. 83db 1 watt and 86db @2.83volts

Yeah, That is what I picked up as well. I do understand the 83db 1 watt, and further math behind it, when the room gets bigger / the sound gets louder. Howeer, Whats the story with the 86db @2.83 how does that get into play with amplifiers?

-> Together with the first, above, they are 4ohm speakers....nominal.

Yes, however, similar to emotiva with the X Watt per Channel, they make a strong claim, that their speaker are really delivering on the 4ohm's claimed (other than many 8ohm speaker). However, could this pose an issue here?

-> Multiple speakers of this type will require a 'better than average' amp to get the most out of 'em......

Yes, that is what I was suspecting. Therefore I got the sdr2 (to drive two nuvero 110) and an sdr3 (to drive the nuvero 60 and two 140). What means "Better than average"? Can sdr2 / sdr3 be considered "above average"? I am aware that in the hifi community "above average" can be very much subject to be debated. For me some random Sonos speaker is "above average" ;-).

-> Other specs listed but my German is a LITTLE Rusty.....!

What else could be important? I could happily translate. Maybe also the nominal power handling (DIN EN 60268-5, 300 h), which is at 440W for the 140 and 280W for the 60.

-> You may just have to turn the volume down a little bit...

Could be it. But I believe that I was able to play them louder with the XPA9 without ever going into protection mode (did not measure it though). Is it possible, that the sdr2/sdr3 is stricter, and quicker goes to protection mode? Could there also be something wrong with the speaker cables (I replace one one adding the new amps)? Is it possible that the sdr3 throws more watt into the speaker, without them playing louder?

Maybe some of the questions are stupid, if so, I do hope for lenience ;-)

Further I just noted, that I put my post into the legacy amp part of the forum. I guess this is not really correct. sry, for that. Maybe this can be moved.

1 watt at 8 ohms is 2.83 volts.     1 watt at 4 ohms is 2.0 volts.        When you  double or 'halve' the POWER you increase or decrease by 3db.......So?   the difference in sensitivity between the 2 measures is 3db......

BTW?  This is the FIRST manufacturer I've seen who will go this far in a spec.   Many builders just say......'We have a4 ohm speaker of 86db @ 2.83 volts', which is 2 watts.....NOT 1, at 4 ohms.....

Amplifiers of the SAME WATTAGE are NOT all the same capabiility into any given speaker.    Some speakers are simply More Difficult to 'drive'.    This means a couple things.    The impedance of the speaker may 'dip' to a point that the amplifier is uncomfortable with.    I may also mean that the speaker represents a more REACTIVE load.   This means that while a speaker is generally spec'd as having a certain impedance....which in many cases is just ADVISORY, this same speaker ALSO can look like a capacitor (stores an electrical charge) OR an Inductor. (stores a magnetic 'charge')    Most amplifiers will take a modest amount of this sort of abuse.   But 2 amps which measure IDENTICALLY into a resistor may not respond the same into any given speaker.    Especially one which has big swings in REACTANCE......This reactance is usually measured in DEGREES (plus or minus) with ZERO degees being pure resistive.   One way of the swing is looking more like a capacitor while the OTHER way looks like an inductor.     For purposes of this reply, I'm treating Impedance and Resistance as the same thing, which they technically are NOT....Impedance may be thought of as resistance at a frequency (AC) not the DC used to measure resistance.
NO SUBSTANTIAL agreement exists about a Standard Speaker Load and what it should 'look like' electrically....

Nominal power handling is one of those 'iffy' specs.     Is that similar to what I'm accustomed to calling 'peak power'?        I just generally turn it DOWN if I hear distortion.   I try to keep it simple.

One other thing here......and it is a bit off 'into the weeds' but Copper, while an excellent conductor DOES warm with use in a voice coil.   It has 'resistance' which expresses itself as a tempreture rise.
Don't forget that your entire signal chain from plugging the amplifier into the wall to the sound made by the speaker is MAYBE 5% or 6% efficient.   The rest is HEAT.  As it turns out?    As the Copper warms,
it's electrical characteristics change, too.   And not in 'our' favor.  As temp rises, so does resistance....making things worse.....   I highly stressed speaker may have a voice coil hot enough to fry an egg.....well, maybe not
THAT hot, but for sure it'll burn you if you grab ahold...    Check out the provided link......

www.cirris.com/learning-center/general-testing/special-topics/177-temperature-coefficient-of-copper

[ramirezz]

Hi Everybody, sry for oppening up this old discussion again. However, I still struggling with the setup with the DR3. I now watched about 1000h in movies and games, however, using the DR3 I can not quite turn the volume up loud enough, before it going into protection mode. Same with the DR2 I did end up using my XPA-9 for my front LR and Center again, just to be able to get enought volume in. The XPA-9 never does this. The sound is oke, even in high volumes with the XPA-9. Same cables used in both cases. @keithl recommended to turn down the volume somewhat. That works, however watched HOTD yesterday, the screems of the dragons are just not loud enough like that.

As stated above, its only certain scenes (and I can repeat it for one scene with the same volume at any time). The boxes are not cheap (LR about 2500$ each) and have excellent reviews and reputation in germany. However, I have huge issues with using them with my DR3 and DR2. Any ideas? Maybe the cables nevertheless? I use Mogami 2534 Quad Stereo Audio (Cinch RCA - XLR male) with my Denon 4700 to connect to my Amp:
www.amazon.de/gp/product/B07BLLRJST/ref=ppx_yo_dt_b_asin_title_o04_s00?ie=UTF8&th=1 . From the Amp to the boxes I use 6mm copper cables.

Any Ideas, help? Would hate to sell them, look(ed) so promising and sound awsome as long as no protection mode kicks in.