AVTALK tests #8: PB12NSD, PC13 Ultra, Velo Microvee

[mike c]

test conclusions:
http://www.avtalk.co.uk/forum/index.php?t=msg&th=24673&start=0&rid=7164&SQ=1216247853


PB12NSD
http://www.avtalk.co.uk/forum/index.php?t=msg&th=24671&start=0&rid=7164&SQ=1216247853


PC13Ultra 20hz
http://www.avtalk.co.uk/forum/index.php?t=msg&th=24667&start=0&rid=7164&SQ=1216247853


PC13Ultra 15hz
http://www.avtalk.co.uk/forum/index.php?t=msg&th=24668&start=0&rid=7164&SQ=1216247853


PC13Ultra 10hz
http://www.avtalk.co.uk/forum/index.php?t=msg&th=24669&start=0&rid=7164&SQ=1216247853


PC13Ultra sealed
http://www.avtalk.co.uk/forum/index.php?t=msg&th=24670&start=0&rid=7164&SQ=1216247853


Velodyne Microvee
http://www.avtalk.co.uk/forum/index.php?t=msg&th=24666&start=0&rid=7164&SQ=1216247853

 

[mojomike]

Some of those results are very interesting. The PC13 seems to suffer by comparison to last years's lest of the PB13. The PB12 NSD, on the other hand, looks surprisingly strong.

 

[mike c]

im actually surprised with the PB12NSD ... so basically, it's overdamped? linear but sloping to the low end? but isn't the slope happening too early? no wonder there were two FR ranges on the HTS tests.

the FR differences at the low end are pretty much expected ... but i guess ... i'll go boxes

 

[mojomike]

That gentle sloped, over-damped look to the PB12 rolloff shows almost sealed-like characteristics. It looks like it should sound pretty good with a little room gain.

 

[Sheep]

That gentle sloped, over-damped look to the PB12 rolloff shows almost sealed-like characteristics. It looks like it should sound pretty good with a little room gain.

My thoughts exactly.

SheepStar

 

[Bluesmoke]

It seems like the PC13 ultra is tuned to around 22-23hz. Does anyone what what the correct tuning is for the 20-39PC+, I'm guessing it's not at 20hz either?

 

[mike c]

It seems like the PC13 ultra is tuned to around 22-23hz. Does anyone what what the correct tuning is for the 20-39PC+, I'm guessing it's not at 20hz either?

not sure about tuning, but it hits 18-19hz f3 groundplane no problem

http://www.avtalk.co.uk/forum/index.php?t=msg&th=13934&start=0&rid=14&SQ=1127556133

http://www.avtalk.co.uk/forum/index.php?t=msg&th=13374&start=0&rid=14&SQ=1127556789

http://www.hometheatershack.com/forums/subwoofer-tests/6005-svs-20-39pc-20-hz-tune-db12-2-a.html

http://www.hometheatershack.com/forums/subwoofer-tests/6007-svs-20-39pc-20-hz-tune-db12-1-a.html

 

[cjwhitehouse]

That gentle sloped, over-damped look to the PB12 rolloff shows almost sealed-like characteristics. It looks like it should sound pretty good with a little room gain.

I don't think it's intentional and the FR measurement is at variance with that published on the SVS website. But the results we got agreed with HTS' earlier test using entirely different test subjects. We can only conclude that the measurements are correct rather than a defective unit. The current hypothesis is that it may be something to do with running the sub on 230V/50Hz as opposed to 110V/60Hz. Ed may be in a position to confirm that once he's tested it for himself.

 

[mike c]

FYI: both AVTALK and HTS are 230v

quote from Ed M regarding the recent AVTALK tests.

Yes, the PB12-NSD is exhibiting a slightly overdamped response, which will work extremely well in a room with a bit of gain.

 

[mojomike]

I don't think it's intentional and the FR measurement is at variance with that published on the SVS website. But the results we got agreed with HTS' earlier test using entirely different test subjects. We can only conclude that the measurements are correct rather than a defective unit. The current hypothesis is that it may be something to do with running the sub on 230V/50Hz as opposed to 110V/60Hz. Ed may be in a position to confirm that once he's tested it for himself.

I believe that the graph published on the SVS website might be of the response of the older unit from a couple of years ago. I don't think they replaced the graph when they upgraded the PB12 NSD. The only reason I suggest that the response may be intentionally overdamped is that I know they did this to taylor the deep response of the 13Ultra in order to allow it to compliment the room gain which most rooms present.

 

[mike c]

I believe that the graph published on the SVS website might be of the response of the older unit from a couple of years ago. I don't think they replaced the graph when they upgraded the PB12 NSD. The only reason I suggest that the response may be intentionally overdamped is that I know they did this to taylor the deep response of the 13Ultra in order to allow it to compliment the room gain which most rooms present.

i can understand the ultra 13 overdamped to 12-13hz ... but overdamping the PB12NSD that high up the frequency assuming that the enduser's room is a certain way in terms of room gain? [im not criticizing or saying they are wrong, but im trying to learn how they ended up deciding to overdamp the subwoofer, when they previously aimed for flat frequency response to the teens]

granted, SVS recommends the proper sized sub to the room and overdamping gives a lot more headroom.

but i believe low end room gain is computed by room size, room leakage, and 570.5 divided by the longest side of the room. im guessing people's room sizes are pretty random and ranging from one end of the spectrum to the other. my two rooms for example have a room gain starting at 19hz (ideal) for the 4k room and 25hz for the 3k room.

(i could listen to the PB12NSD myself, but i haven't had the time to take it out of the box yet )

 

[mojomike]

This is just pure speculation on my part, but over the years critics of the "SVS sound" would say something like "Great for movies, but only so-so for music" or something similar to that. I suspect that SVS may have chosen more recently to shape the sound so as to be less bottom-heavy when typical room gain is taken into account. This can make the response a little bit more like a sealed sub which many seem to find more musical. I realize that all rooms are different and will provide different amounts of gain which will also begin at different frequencies, but my understanding about room gain is that the slope would be similar to an inverse of the natural rolloff slope of a sealed sub.

 

[mike c]

good theory ... they did start the "great for music AND HT" thing with the ultra.

 

[Bluesmoke]

(i could listen to the PB12NSD myself, but i haven't had the time to take it out of the box yet )

You know you have way too many subs when you don't have "the time" to open the box of a sub just sitting there.

 

[mike c]

You know you have way too many subs when you don't have "the time" to open the box of a sub just sitting there.

actually, it's just the lack of time.

haven't watched a single movie in my HT since February

 

[Adam]

Thanks for the links and the plots, Mike. Very interesting.

For my experience - with my PC13-Ultra, I tuned it to 15Hz and applied the room correction feature in order to keep the low end frequencies (below 25Hz, if I remember right) from being overly accentuated in my room. It's relatively flat down to 15Hz in my room (the lowest frequency that I measured), outside of a room null around 35Hz that I have.