"System" SINAD

[Sokel]

@Sokel Thanks for taking those measurements and sharing them. Very interesting.

The amount of distortion looks terrible, but I don't have a good frame of reference for such whole system measurements. I bet it is actually a very good result and my own system (that subjectively sounds good) might do a lot worse. It seems like a very good way of testing and maybe trouble-shooting our setups.

Perhaps you have posted details of your system elsewhere, but could you please re-post them here so that we can corellate them with the measurements?

It's easy to get a rough idea looking at Amir's measurements,of course mine is not ideal (far-far from it,only the fact that is in an actuall room 2.8 meters at MPL is enough to screw things up big time) but you get a rough picture.

Here's a very good speaker in comparison

(I'll say it again,my measurements are not comparable to this state of the art ones)

My system is a little unusual as it's installed by professionals,it was the only way to get some decent sound at my big dedicated room (not yet fully treated,low needs another round of not quite cheap stuff).
Speakers are big-ish (around 150 litters) 3-way semi-actives powered by Ice power 1200as2 for lows and 300a2 for mid-highs.
Everything else is pretty much average.

 

[tktran303]

Thanks @Sokel

The distortion may look “terrible” to some readers, but only because your graphics contains lots of data. Consider greying out things below noise floor; or alternatively, not showing H6+

That is a formidable system-

Smooth in-room response
Extension down to 31.5Hz WITH high SPL
Monotonically decreasing distortion with frequency
H3 always less than H2, and low high order harmonics
100dB at LP @2.8m- that’s almost 109dB @1m!
If that’s only 1 speaker playing… heck, even if it’s a pair playing…

Most Impressive!

My guess is that you have plenty of woofers. The equivalent of a least 2 15” woofers is my scientific wild arse guess

 

[Sokel]

Thanks @Sokel

The distortion may “terrible” to some readers, but only because your graphics contain it has a lot of data. Consider greying out things below noise floor; or alternatively, not showing H6+

That is a formidable system-

Smooth in-room response
Extension down to 31.5Hz WITH high SPL
Monotonically decreasing distortion with frequency
H3 always less than H2, Low high order harmonics
100dB at LP @2.8m- that’s almost 109dB @1m!
If that’s only 1 speaker playing… heck, even if it’s a pair playing…

Most Impressive!

My guess is that you have plenty of woofers. The equivalent of a least 2 15” woofers is my scientific wild arse guess

Yes,that's the right speaker,both speakers together result in an odd high-freq extension when I have set the mic distance with the laser measure which is precise.
If I move it to miss even 0.5 cm it looks ok.
Of course I use EQ to iron low's a little.The downside of my big room is I will never have RT under 0.6 s but at least is smooth up there.

 

[Sokel]

My guess is that you have plenty of woofers. The equivalent of a least 2 15” woofers is my scientific wild arse guess

What you see it's only a 10" scanspek in a 110 litters ported enclosure (the rest is for the sealed mid-highs),room and port helps with that 31Hz.
I have a amateur near-field (not isolated,mid-highs where playing also) for those:

and their distortion chart:

Ok,now I will say something that can be viewed both ways.
If I swamp the amps and put the weakest (icePower 300a2) at lows distortion goes way up,but highs get a small hit too (probably by the lower specs of 1200as2).
So either good power does a good job or 300a2 is not up to the task regardless having a good amount of power too.

Edit:Typos,bad English.etc

 

[-Matt-]

The distortion may look “terrible” to some readers, but only because your graphics contains lots of data. Consider greying out things below noise floor; or alternatively, not showing H6+

It wasn't particularly the complexity of the graph (I could still see where the noise floor was). It's more that I'm used to looking at dac and amp graphs with over 100dB of SINAD rather than loudspeaker (or whole system) measurements.

Obviously, in an ideal world, you'd want the total harmonic distortion to be below the noise floor. It is therefore quite shocking to see distortion 10s of dB above this (even though this is quite normal for speakers at high spl). This should serve as a reminder that speakers are the part of the audio reproduction chain that are in most desperate need of radical technological development and improvement. Worrying about dac SINAD in this context seems totallyrather pointless!

 

[Sokel]

It wasn't particularly the complexity of the graph (I could still see where the noise floor was). It's more that I'm used to looking at dac and amp graphs with over 100dB of SINAD rather than loudspeaker (or whole system) measurements.

Obviously, in an ideal world, you'd want the total harmonic distortion to be below the noise floor. It is therefore quite shocking to see distortion 10s of dB above this (even though this is quite normal for speakers). This should serve as a reminder that speakers are the part of the audio reproduction chain that are in most desperate need of radical technological development and improvement. Worrying about dac SINAD in this context seems totally pointless!

First pic I posted in this thread has labeled "reminder" exactly for that reason,to remind me to calm down when I "chase" couple of db's of performance when setting my gear.

 

[mwmkravchenko]

It wasn't particularly the complexity of the graph (I could still see where the noise floor was). It's more that I'm used to looking at dac and amp graphs with over 100dB of SINAD rather than loudspeaker (or whole system) measurements.

Obviously, in an ideal world, you'd want the total harmonic distortion to be below the noise floor. It is therefore quite shocking to see distortion 10s of dB above this (even though this is quite normal for speakers at high spl). This should serve as a reminder that speakers are the part of the audio reproduction chain that are in most desperate need of radical technological development and improvement. Worrying about dac SINAD in this context seems totallyrather pointless!

Even the 85b measurement at listening position, which is quite loud, ( you will have trouble shouting over this) has great distortion figures. As mentioned you can hide a few of those curves and still convey more than enough information. THD is nearly useless. Having the harmonics there is great. But including harmonics that are already well below 0.5% distortion is really pointless. Area of greatest interest is the voice range. about 300 hertz to 4 khertz. And then the bass. Once you hear and understand low frequency distortion you will always hear it.

A true test of your amps. May I suggest replacements. No well designed amplifier should be adding that much distortion.

Mark

 

[Sokel]

Even the 85b measurement at listening position, which is quite loud, ( you will have trouble shouting over this) has great distortion figures. As mentioned you can hide a few of those curves and still convey more than enough information. THD is nearly useless. Having the harmonics there is great. But including harmonics that are already well below 0.5% distortion is really pointless. Area of greatest interest is the voice range. about 300 hertz to 4 khertz. And then the bass. Once you hear and understand low frequency distortion you will always hear it.

A true test of your amps. May I suggest replacements. No well designed amplifier should be adding that much distortion.

Mark

The 25Hz distortion seems a lot,I know.
But it's probably because the speakers can't do 25,their f3 is at 31.5hz.
This must be the port which is about at that freq.

For lows (30-240Hz) I have an 1200as2 which is the module inside this amp but without the "audiophile" buffer which looks nice at that range:

 

[mwmkravchenko]

The 25Hz distortion seems a lot,I know.
But it's probably because the speakers can't do 25,their f3 is at 31.5hz.
This must be the port which is about at that freq.

For lows (30-240Hz) I have an 1200as2 which is the module inside this amp but without the "audiophile" buffer which looks nice at that range:


View attachment 343051

It's always the saying there's no replacement for displacement. But that is not totally true. You can lever a driver into a proper front loaded horn and trade bandwidth for efficiency. I have designed a few custom home theaters that had a 104 db per watt efficiency across the board from 10 hertz up to about 8k. We never do get to actually measure top SPL as nobody ever wants to put their building through that! but peaks in excess of 140 are seriously not a big deal when you have 8 subwoofer horns hiding in your listening room. Oh, and as you are probably calculating you can break drywall with a real 250 watt amp connected to such a system. Distortion is also below 1 percent all across the board.

Mark

 

[Sokel]

It's always the saying there's no replacement for displacement. But that is not totally true. You can lever a driver into a proper front loaded horn and trade bandwidth for efficiency. I have designed a few custom home theaters that had a 104 db per watt efficiency across the board from 10 hertz up to about 8k. We never do get to actually measure top SPL as nobody ever wants to put their building through that! but peaks in excess of 140 are seriously not a big deal when you have 8 subwoofer horns hiding in your listening room. Oh, and as you are probably calculating you can break drywall with a real 250 watt amp connected to such a system. Distortion is also below 1 percent all across the board.

Mark

Oh,you talk about subs,that's different.
There's no sub here,is just a semi-active 3-way for 2ch music.
No way I can do 140db and I'll be happy if I can do 110-115db!

 

[Ron Texas]

My Crown XLS 1502 with its seemingly low 76 dB SINAD produces no audible hiss when played through my very inefficient LS50 speakers. However, inexpensive active speakers often produce audible hiss when used near field. The takeaway is if you can't hear noise, it isn't there and if you can hear it, getting rid of it is difficult.