Ultimate Bass

[jap]

http://www.avsforum.com/t/1525580/ht-of-the-month-ultimate-bass

My favorite quote from the article:

When I asked about power conditioning, Rob scoffed. "In my opinion, power conditioning is a joke. Voltage is converted to DC and regulated in all the electronics; it doesn't matter how precise the waveform is. Maybe if it's REALLY bad, like if you live in a third-world country or something, conditioning might be important, but not where I live."

 

[microstrip]

http://www.avsforum.com/t/1525580/ht-of-the-month-ultimate-bass

My favorite quote from the article:

When I asked about power conditioning, Rob scoffed. "In my opinion, power conditioning is a joke. Voltage is converted to DC and regulated in all the electronics; it doesn't matter how precise the waveform is. Maybe if it's REALLY bad, like if you live in a third-world country or something, conditioning might be important, but not where I live."

Jap,

The article and opinions are about a multichannel system - very different situation from the stereo systems we debate in General Audio Discussions.

 

[jap]

Jap,

The article and opinions are about a multichannel system - very different situation from the stereo systems we debate in General Audio Discussions.

So, AC power conditioning is more critical in a stereo system?

 

[microstrip]

So, AC power conditioning is more critical in a stereo system?

Although I have very limited experience with AV systems I would expect it. Multichannel is a much more predictable system, that does not depend so much on the interpretation of the small cues needed to create the illusion as stereo. But we should listen to the AV experts.

 

[edorr]

Listening to a fine MCH SACD power is just as critical as in a stereo system.

Blowing the windows out of the house with a killer bass reproducing system may be not so much.

 

[dallasjustice]

It looks like all the subs are on the frontwalll of the room. I would love to see the LF measurements of this room. I bet the bass is not that "ultimate."

 

[GaryProtein]

It looks like all the subs are on the frontwalll of the room. I would love to see the LF measurements of this room. I bet the bass is not that "ultimate."

Quite likely, but I bet its really loud!

 

[mojave]

It looks like all the subs are on the front wall of the room. I would love to see the LF measurements of this room. I bet the bass is not that "ultimate."

You won't find much better than this. The distortion is so low, the frequency response so smooth, and the dynamics so incredible that most will never experience this level of bass refinement - using what are considered the finest subwoofer drivers made. The complete sub system is about $13,000.
No smoothing:

And in room results. There's a null at 80hz where the mic is placed.

Complete system response in-room. ±3 dB from 10Hz-20kHz capable of 130+ dB.

 

[dallasjustice]

You won't find much better than this. The distortion is so low, the frequency response so smooth, and the dynamics so incredible that most will never experience this level of bass refinement - using what are considered the finest subwoofer drivers made. The complete sub system is about $13,000.
No smoothing:

Complete system response in-room. ±3 dB from 10Hz-20kHz capable of 130+ dB.

Mojave,
If there is a null at 80hz you would see the 180 degree phase shift in the first graph (SPL plus phase). The first graph looks fishy to me. You would see some phase shifts at the seated position at HF. Something isn't right with these.

 

[dallasjustice]

You won't find much better than this. The distortion is so low, the frequency response so smooth, and the dynamics so incredible that most will never experience this level of bass refinement - using what are considered the finest subwoofer drivers made. The complete sub system is about $13,000.
No smoothing:

Complete system response in-room. ±3 dB from 10Hz-20kHz capable of 130+ dB.

Mojave,
If there is a null at 80hz you would see the 180 degree phase shift in the first graph (SPL plus phase). The first graph looks fishy to me. You would see some phase shifts at the seated position at HF. Something isn't right with these.

 

[mojave]

He doesn't have the phase box checked so I'm not sure what you are talking about. Rob has a calibrated microphone and has done a microphone shootout in the past so I'm pretty sure his measurements are fine. He has done quite a few measurements of this system including comparisons to when he had the drivers in sealed enclosures.

Just for comparison, here a measurement I took this past weekend of a subwoofer. This is the native response with SPL & Phase (No smoothing)



I then left everything the same and moved the microphone to the listening position. You can see that the phase changes due to the room interactions. It said in the legend on the first graph that the phase was 5.7 deg. On the second graph it said 68 deg. (No smoothing)



Finally, I added in the speaker, corrected SPL and Phase with Audiolense, and got this (1/6th octave smoothing):

 

[dallasjustice]

If he is claiming to have the "ultimate" bass or something, he would need to show some kind of time/phase information to convince me. Just showing SPL doesn't say much about what it sounds like.

 

[dallasjustice]

Finally, I added in the speaker, corrected SPL and Phase with Audiolense, and got this (1/6th octave smoothing):

View attachment 15129

This looks fantastic! I wish I could figure out how to measure in REW with my DIRAC output. I need to work a bit more on it.

 

[audioguy]

If he is claiming to have the "ultimate" bass or something, he would need to show some kind of time/phase information to convince me. Just showing SPL doesn't say much about what it sounds like.

Bass "ringing" provides much more about what it actually sounds like.

 

[dallasjustice]

Bass "ringing" provides much more about what it actually sounds like.

Right. For example, a waterfall graph would be useful. Also, if there's a null at 80hz, I know that won't sound like ultimate bass to me. I know that nulls can be be swept under the rug in a simple FR graph. I've done it. The graph will look better but the sound will be weird sounding due to the excessive boost at the null frequency.

I bet he could easily eliminate the null if he had some woofery on walls other than front, depending on which boundary caused the null. Phase shifts at the nulls will look just like what mojave showed before he applied correction in the middle of his second graph post #11.

Sometimes I think REW is an incredibly powerful and useful tool for diagnosing and curing real room issues. Other times, I wonder whether it can become a distraction. Using REW to prove bass perfection is tough.

Michael.

 

[Young Skywalker]

A vented box will never give the ultimate possible bass response.

 

[mojave]

A vented box will never give the ultimate possible bass response.

He has had at least 3 sealed systems before. This time he took the same drivers out of his sealed subs and made ported subs. He likes the ported system better. Most change drivers, amps, and DSP (mfg built into the amp) in comparing alignments. In this case, the only variable is the cabinet itself.

Here is his previous setup:

And current setup:

Group Delay differences of the two alignments is insignificant where it matters:

 

[dallasjustice]

He has had at least 3 sealed systems before. This time he took the same drivers out of his sealed subs and made ported subs. He likes the ported system better. Most change drivers, amps, and DSP (mfg built into the amp) in comparing alignments. In this case, the only variable is the cabinet itself.

Here is his previous setup:

And current setup:

Group Delay differences of the two alignments is insignificant where it matters:

It looks like group delay is a little worse in the sealed cabinet at 200hz, no? If the subs play that high.