Velodyne HGS-18 vs. SVS PB2-Plus (1 Viewer)

[Doug BW]

Playing a 98 db sound for 30 hz and 107 db sound for 55 hz (when it should or could be 107 db for 30hz and 107 db for 55 hz) would not be desirable for me given the amount of money involved. The Ultra errors in an manner where the human hearing is less senstive and having an added bump at 30 hz may be a benefit. If not it should be fairly easy to equalize that hump down.

My read on the Weatherhead review was always quite different than this. His charts were not "typical" Frequency Response graphs, in the sense they were measured at moderate volumes. Rather, Weatherhead cranked up the volume till he believed he was hearing distortion and then measured FR.

To quote from the article: "Frequency sweeps were run from 10 Hz to 100 Hz. The volume was raised little by little until the sonic quality started to change."

My understanding of servo-control may be seriously flawed, but I believe that what you're seeing with 10 dB drop-off in the HGS chart is the servo kicking in at extreme volume under 55 hz. That is, if Weatherhead had reduced the master volume by 10 dB, the HGS may have measured flat down to 20 hz.

If this is truly the case, it shows a flaw in Weatherhead's methodology, in that his ears didn't pick up on the severe change in FR as he raised the volume.

If this is NOT the case....if the FR of the HGS would be the same if measured at a lower volume...then the bass extension (i.e., the -3dB point) of an HGS-18 is apparently only around 50 hz. And I somehow doubt this.

Regarding the hump at 30 hz... Pretty much all the subs that Weatherhead measured showed a hump at about 32 hz. I think it's a fair guess that the hump is produced by Weatherhead's room, not the subs.

 

[Mike Sloan]

Anthony_Gomez,

Do you have any pictures of the Everest?

 

[Anthony_Gomez]

One one everest has been built and one Denali (at the moment) and the Everest should probably be on it's way to Kyle as we speak.

 

[Zack_R]

Regarding the hump at 30 hz... Pretty much all the subs that Weatherhead measured showed a hump at about 32 hz. I think it's a fair guess that the hump is produced by Weatherhead's room, not the subs.

I agree and makes the Ultras seem even better from a flatness standpoint at max volume. Weatherhead also thought (for what it's worth) they could have played a little louder but the amp began to clip on him.

I also would assume that the HGS was limited at max volume by the servo on the frequency sweeps. This is why it would have been nice to have seen a frequency sweep at 100 db for all subs to correspond with the music test. I have to believe Brian would have heard a difference had their been one but it would have been nice to have the graphs validate thist issue.

I can see how this imbalance of sound could be a potential shortcoming for people that like to play movies, containing loud dynamic bass, near or at reference levels or who like to run their sub a few dbs hot. Then again, unless you had a sub to a/b against, you probably wouldn't be aware that an inbalance existed since the HGS is capable of extending deep at pretty loud volumes anyway.

 

[Doug BW]

I have to believe Brian would have heard a difference had their been one but it would have been nice to have the graphs validate thist issue.

Perhaps. On the other hand, he may have been listening for the presence of distortion, not the tapering off of low bass. It's easier to perceive the presence of something extra than the absence of something that's supposed to be there.

Also, if you think about the Fletcher-Munson curves, as you turn up the volume, lower bass becomes proportionately louder (to the ear) compared to upper bass. So this would make it harder to hear the change in FR.