AHB2 Mono v Stereo - what is audible?

[SIY]

If I understand the theme of level matching correctly, it seems to be to find a linear way of trying to match two non-linear responses; bridged versus stereo amplification into a speaker.

Voltage AND current delivery can change the behaviour of the speaker. Measuring voltage at one nominal frequency only does that - it leaves everything else unmatched essentially (to my thinking).

My idea with using pink noise was that I would be averaging any differences (voltage, curent) at various frequencies, and getting closer to like for like AUDIBLY.

And yes, I failed to accurately match the levels - part of doing so many recordings I suspect. But FOOBAR matches the levels, and like I stated previously, if you do the true blind test with the 2 tracks and can hear what the difference is, and post your results - we have a starting point.

It might be possible that after 100 people have tried this, the actual current 100% success rate might drop somewhat.....

Pink noise.

 

[richard12511]

Airport. Jets have some low frequency rumbles for sure - I see them in my measurements far more often than I want. However, I am fairly sure during the 2 recordings such ambient noises were not audible. I actually made about 6 recordings and selected the cleanest 2.....

Interesting, train or airplane was actually my first guess when I heard it.

 

[richard12511]

If I understand the theme of level matching correctly, it seems to be to find a linear way of trying to match two non-linear responses; bridged versus stereo amplification into a speaker.

Voltage AND current delivery can change the behaviour of the speaker. Measuring voltage at one nominal frequency only does that - it leaves everything else unmatched essentially (to my thinking).

My idea with using pink noise was that I would be averaging any differences (voltage, curent) at various frequencies, and getting closer to like for like AUDIBLY.

And yes, I failed to accurately match the levels - part of doing so many recordings I suspect. But FOOBAR matches the levels, and like I stated previously, if you do the true blind test with the 2 tracks and can hear what the difference is, and post your results - we have a starting point.

It might be possible that after 100 people have tried this, the actual current 100% success rate might drop somewhat.....

Guess I need to download Foobar.

 

[restorer-john]

Guess I need to download Foobar.

I only downloaded it for the ABX plugin functionality, which is rather useful.

(highlight the two tracks in the main window, right click on the highlighted tracks, then select Utilities, roll down to ABX tracks)

 

[Pdxwayne]

OP, you are not pulling my leg, right? The differences so obvious....

 

[SIY]

OP, you are not pulling my leg, right? The differences so obvious....

Yes, indeed it is. The level matching is not adequate.

 

[restorer-john]

Yes, indeed it is. The level matching is not adequate.

Level differences were addressed in post #2 in this thread.

 

[restorer-john]

OP, you are not pulling my leg, right? The differences so obvious....

View attachment 136071

Expand the Foobar ABX window so we can see the tracks were level matched.

Like this:

 

[Pdxwayne]

Expand the Foobar ABX window so we can see the tracks were level matched.

Like this:
View attachment 136090

I see. This is the first time I use foobar2000.

I tried to use Replaygain to adjust. Here is it again. The bass is a very good tell....

 

[Coach_Kaarlo]

OP, you are not pulling my leg, right? The differences so obvious....

View attachment 136071

For the record I don't believe all amps sound the same, because the only time they make a sound is when connected to speakers, which change the way the amps sound.

And yes the difference is quite obvious even with a poor recording.

 

[Pdxwayne]

For the record I don't believe all amps sound the same, because the only time they make a sound is when connected to speakers, which change the way the amps sound.

And yes the difference is quite obvious even with a poor recording.

The only time I compared stereo vs bridged mono was with my Parasound A23. I didn't like the sound of bridged mono and have stayed with stereo since. I read the measurements of Parasound amps recently and bridged mono measured poorly.... pretty much confirmed my observations.

In your case, which do you prefer?

 

[Coach_Kaarlo]

The only time I compared stereo vs bridged mono was with my Parasound A23. I didn't like the sound of bridged mono and have stayed with stereo since. I read the measurements of Parasound amps recently and bridged mono measured poorly.... pretty much confirmed my observations.

In your case, which do you prefer?

If I had enough power to run the amps in stereo then I would, but at the moment the AHB2's are way under powered for such use case with anything but the most sensitive easy to drive speakers. Or little studio boxes..... Long term plan is to transition to a fully active system with an AHB2 for treble and one for mid, and one of the new Purifi amps for the woofer.

 

[restorer-john]

The only time I compared stereo vs bridged mono was with my Parasound A23. I didn't like the sound of bridged mono and have stayed with stereo since. I read the measurements of Parasound amps recently and bridged mono measured poorly.... pretty much confirmed my observations.

The thing with bridging your amp is you increase noise and gain. It can be audible immediately and unless you turn down the gain pots (if you have them), and match the overall gain to what you had before, the volume control range you are used to becomes less and squashed at the low end. ie. The amp gets louder faster and doesn't seem "right".

Those changes can be interpreted as not good to us, as many humans don't really like change.

Unless you have three identical amplifiers (two stereo in BTL mode and one in stereo mode) and a switcher that can handle balanced output amps, the time taken to switch to mono and reconnect the speaker terminals takes time. Much longer than our short term memory for sure. That's where @Coach_Kaarlo tried to make identical recordings for A/B purposes.

I've done it with my comparator and the three Sony TAN77es power amps I have. Once gain matched and the meters turned off (slight differences in meter readings from driven unloaded to driven loaded can be a visual clue), it was virtually impossible to hear a difference if I didn't get close enough to the speakers to hear residual noise. Other amplifiers it's a different story for sure and much easier, but I don't have that many identical power amps that can be run in BTL pairs.

 

[Coach_Kaarlo]

The only time I compared stereo vs bridged mono was with my Parasound A23. I didn't like the sound of bridged mono and have stayed with stereo since. I read the measurements of Parasound amps recently and bridged mono measured poorly.... pretty much confirmed my observations.

In your case, which do you prefer?

Which is to say I prefer mono. One amp per speaker. The bass is always lacking in stereo as we have noticed....

 

[restorer-john]

Long term plan is to transition to a fully active system with an AHB2 for treble and one for mid, and one of the new Purifi amps for the woofer.

I think I need to build you some tweeter and midrange protectors.

 

[Coach_Kaarlo]

I think I need to build you some tweeter and midrange protectors.

I think I need to [remind myself] sort you out for the last favour you did me before we start new things!!!!

 

[Coach_Kaarlo]

I think I need to build you some tweeter and midrange protectors.

Once I own some speakers with decent drivers that is....Yamaha's BE mid and tweeter......or maybe some of the new zylon nones.....

 

[Pdxwayne]

The thing with bridging your amp is you increase noise and gain. It can be audible immediately and unless you turn down the gain pots (if you have them), and match the overall gain to what you had before, the volume control range you are used to becomes less and squashed at the low end. ie. The amp gets louder faster and doesn't seem "right".

Those changes can be interpreted as not good to us, as many humans don't really like change.

Unless you have three identical amplifiers (two stereo in BTL mode and one in stereo mode) and a switcher that can handle balanced output amps, the time taken to switch to mono and reconnect the speaker terminals takes time. Much longer than our short term memory for sure. That's where @Coach_Kaarlo tried to make identical recordings for A/B purposes.

I've done it with my comparator and the three Sony TAN77es power amps I have. Once gain matched and the meters turned off (slight differences in meter readings from driven unloaded to driven loaded can be a visual clue), it was virtually impossible to hear a difference if I didn't get close enough to the speakers to hear residual noise. Other amplifiers it's a different story for sure and much easier, but I don't have that many identical power amps that can be run in BTL pairs.

Not sure if ~0.0035 vs ~0.012 (3khz distortion and noise when playing 1khz at 10W) is audible or not....But I would assume at higher watts, the differences can be audible?

This is from Soundstagenetwork.com for Parasound A23

 

[SIY]

I spotted something interesting here...

 

[restorer-john]

I spotted something interesting here...

Really, seriously...?

Just take the two original files, let Foobar auto level match them (which it does a damn good job of doing), and do a genuine ABX and post your results complete with the level trim and the hash as it shows on the window (fully expanded)

Not hard at all.