I'm looking to upgrade my 2 subwoofers soon. Any recommendations?

[Pogre]

Have a good trip.
Sweep it at 75 and whatever loudness you are willing to endure with earplugs for a few seconds.
Can it be overlapped afterwards for differences to be obvious?

Oh yeah. I can do an overlay. I've done 15-300 hz sweeps playing with my house curve and was hitting like 95db unintentionally with no problem.

This is from last month. It's the house curve I was playing with. I've recalibrated since, but I always do these sweeps with the volume set at -25. This is in 2 port open, eq2 mode (more headroom mode) and they never even broke a sweat.

 

[agarwalro]

View attachment 22636
This is from last month. It's the house curve I was playing with. I've recalibrated since, but I always do these sweeps with the volume set at -25. This is in 2 port open, eq2 mode (more headroom mode) and they never even broke a sweat.

Show off those tight curves! .

 

[mtrycrafts]

Oh yeah. I can do an overlay. I've done 15-300 hz sweeps playing with my house curve and was hitting like 95db unintentionally with no problem.

View attachment 22636
This is from last month. It's the house curve I was playing with. I've recalibrated since, but I always do these sweeps with the volume set at -25. This is in 2 port open, eq2 mode (more headroom mode) and they never even broke a sweat.

Does it look similar at 75 dB?

 

[mtrycrafts]

...
By far, the best piece of research done on the audibility of distortion in bass frequencies was done by Louis Fielder and Eric Benjamin:
Fielder, Louis D., and Eric M. Benjamin. "Subwoofer performance for accurate reproduction of music." Journal of the Audio Engineering Society 36.6 (1988): 443-456.

In fact, it is pretty much the only serious study that has been conducted on this subject.

I had a chance to get a copy of that paper.
Yes, his distortion levels with pure tones and a headphone are lower than 10% with the 2nd harmonic and gets lower further out.
Sounds like they established thresholds with the most revealing test signals.
But then, what are the levels with program material? I would guess it is well above their threshold levels. I think that is what the Axiom paper tries to show, real world program material.

 

[shadyJ]

I had a chance to get a copy of that paper.
Yes, his distortion levels with pure tones and a headphone are lower than 10% with the 2nd harmonic and gets lower further out.
Sounds like they established thresholds with the most revealing test signals.
But then, what are the levels with program material? I would guess it is well above their threshold levels. I think that is what the Axiom paper tries to show, real world program material.

What is program material? That could be anything. The reason to use test tones is to look at worst case scenarios. The axiom paper only shows that complex content can mask pure tones, but that is it. Their testing is only good for those particular recordings. Their testing is of so little interest because it doesn't reveal anything significant.

 

[Pogre]

Does it look similar at 75 dB?

Nope. Looks similar to 95 db...

 

[mtrycrafts]

What is program material? That could be anything. The reason to use test tones is to look at worst case scenarios. The axiom paper only shows that complex content can mask pure tones, but that is it. Their testing is only good for those particular recordings. Their testing is of so little interest because it doesn't reveal anything significant.

Yes, program is anything and yes test tones establish the lowest thresholds. Same as detecting minimum level change (JND) at about 0.2dB with test tones but not with anything other than test tones.

Same with distortion. We don't listen to test tones, so detecting THD in real world program will be higher. How much? That depends on the program, yes.

ps, Fielder and Benjamin also tested with program material:
Hindemith Organ Sonata
Add 2-3 % THD

 

[mtrycrafts]

Nope. Looks similar to 95 db...

I guess your two graphs shows two different conditions now that I look at it again.

 

[Pogre]

I guess your two graphs shows two different conditions now that I look at it again.

The first one is with no eq or level adjustments at all. That last one is a house curve I was playing with. I was surprised it was 95db when I measured. That's what I meant when I said I hit it accidentally.

 

[shadyJ]

The first one is with no eq or level adjustments at all. That last one is a house curve I was playing with. I was surprised it was 95db when I measured. That's what I meant when I said I hit it accidentally.

Have you tried to measure a maximum output sweep? The Hsu subs can take it, their filters will protect the drivers. You should see what they can do! That is probably something you will not want the wife around for, however.

 

[Pogre]

Have you tried to measure a maximum output sweep? The Hsu subs can take it, their filters will protect the drivers. You should see what they can do! That is probably something you will not want the wife around for, however.

I never did. When I get back home I might. I'm at my sister's this weekend. I'm officially curious now. I know I can hit 105dB with no problem and it sounds and measures the same. That last 10 tho... we'll see.