PB2 + and Port Blocking (1 Viewer)

[TommyL]

Hey Steve..with those number...basically, you are getting something for nothin...higher spls at lower Freq...or am I reading it wrong? I should try a port block in my B4...now you have me curious

 

[steve nn]

I here you Tommy. From 26 hz on up it swings the other way just a db or two. That's totaly fine with me. If I were to recalibrate with out the port plugs I think the gap would increase. I know it would. It is only a coupe of notches difrerence on my receiver in calibration. Hay Tommy did I mention I will be receiving my third 25-31cs+ next tuesday. Just one more sub please.

 

[Edward J M]

Tommy - there is no free lunch. You never get something for nothing in the world of subwoofing. If you plug a port, you will gain extension at the expense of a loss of output.

With the B4+ in your size room, you may never notice the loss of output, although it will manifest itself at the limits of the sub. So in your case, you might really have nothing to lose unless you push the sub to its limits (which I have read you have a tendency to do occasionally with 130 dB Matrix demos). :b

David - a higher potential to bottom the sub is about the only concern with the 3/16 setting. I have yet to bottom mine at -10 Reference Level on LOTR-TTT with the sub running 4 dB hot in a 2000 ft3 room. I'm hitting 115 dB on the SPL meter C-Weighted Fast on the big bass hits, and that's about 120 dB actual SPL at an estimated 25 Hz with no signs of strain.

Like all things, the 3/16 setting is a compromise. It probably doesn't dig quite as deeply as the 2/20 setting, but it's close and offers more overall output. It takes a LOT to bottom dual Plus drivers, but it can be done. The SS filter really minimizes that potential and that's why SVS includes it. Bypassing that safety feature to gain additional extension from the stock tune must be approached with common sense.

The sub will definitely play deeper in the 3/16 setting as compared to the 3/25 setting. The 3/25 setting very aggressively knocks down the curve at 21-22 Hz. The difference between the two settings is quite noticeable on the Daredevil bar fight scene, which has a bunch of subsonic stuff. The 3/25 setting cuts out a few critical seconds of infrasonics in that scene, whereas the 3/16 setting lets it all hang out. Cone excursion at -10 RL is MAJOR (I'd estimate 20-23 mm) during those parts with the 3/16 setting, and I'm probably getting close to bottoming the drivers at that volume setting. Cone excursion is much less during the same infrasonic passages with the 3/25 or 2/20 setting, as expected.

Regards,

Ed

 

[MikeLi]

You know whats coming next dont you... you need to have your new HD tv ISF'd for $500. I think I see speaker calibrators on the horizon....

 

[steve nn]

I have noticed on the few occasions when I decided to see what I could get out of my dual set-up that my drivers seem to come to a halt at 120 db corrected in my 2880 cubic ft HT and thats with them tuned to 25 hz.(stock) If I push them a little more there is no gain which in my mind is a big warning! Bottoming out the drivers is right around the corner. I can gain a couple db's by putting a 1/2 sheet of plywood over the bottom 1/2 of a entrance that is very close to sub placement but it is not needed and WAF. If I were to try to hit 120 db's with the subs in the 20 hz tune, I most assuredly would bottom them out I would think.

 

[TommyL]

3 subs huh? hmmm...must be a challenge lol...yes, I could fit another B4+ in my room, but I know damn well my wife wouldn't go for it..lol....she can't handle the bass with one let alone another 6-8 db gain from 2...

Ed...I think you know what I mean...I know you don't get something for nothin...but really to a certain point, you do..unless you go gonzo, and really crank er up....I would be one way that I could get more "feel" at a lower volume...that is what I'm after...not for me, but for my wife 130db...and as TV stated, my K1 is the only thing that will hold me back...I did run a few numbers by TV...he said corrected versions of 125-128db (approx) would yield lower 130's...my room must be set up very good for this testing...I may fiddle tonight...wife is leaving town...I wanna get on that port plugged matrix scene, and see what it'll give..muhahaha!

 

[TommyL]

BTW...I bought that blue man group dvd-a disc...first song with all the drums....The B4 eat it for an appetizer...has the PB2 took it on yet? The organs in daredevil sent me ringing...literally for 2 hours after...ears hurt..which isn't good err :frowning:

 

[steve nn]

Your a hoot Tommy. I know you sure have fun with your B4+. I would also If I had one. I do need to warn you I am approaching though. Tom says I will be 3-6 dbs away from it in the 20 hz tune next week. I,ll pull the plugs and let her rip when I have four just to see. No challenge from me Tommy. I just like to have fun and when you here me bragging it is not really bragging if you know what I mean? I need to figure out a way to sneak another in the house though. Maybe Ed will let me borrow his shop vac also?

I went ahead and did the first (Fly-by) scene in SW II in the 20 hz mode and this is what I came up with. I had my finger on the pause button so I could be very quick to pause at the first sign of bottoming. At -0 it started to bottom at 114db. I then played it at -5 and I hit 112db. Add 3.4 for correction. In the 25hz tune I can achieve 117-118 add 3.4 .... So like Ed says there is no free lunch. -10 is about as loud as I will generally listen at though, so I don't have a problem in the 20hz option. I have a tendency to change options on a weekly basis at times to. I do notice a differenc in the lower hz material more favorable/authority in the 20hz tune. That first Fly-by can be a real sub killer if your not careful just like the THX ball intro.

 

[Zack_R]

Steve,

Since the fly-by scene goes down pretty stong to 20 Hz, you could probably estimate a correction factor of 2-3 dbs more for the 20 Hz tune as the loudest portion will be in the 20-22 hz range.

 

[TommyL]

Same here Steve...no one needs to brag to another about SVS...we all know what they produce..and really, numbers are numbers...as long as I'm happy and everything works...I'm in good shape..just lucky I found the 2 forums to get this great piece of equipment..I'm gonna go plug the thx intro in now...wife is gone...maybe try a port block also..just for kicks keep us informed on the next svs...I like hearing the stories... tom

 

[KeithY]

BTW...I bought that blue man group dvd-a
disc...first song with all the drums....The B4 eat it for
an appetizer...has the PB2 took it on yet? The organs in
daredevil sent me ringing...literally for 2 hours
after...ears hurt..which isn't good err

Had the Blue Man cranked to -5 below reference, the sub
was rockin'(not literally), then at that point in
Mandelgroove where all the drums kick in everything on the
shelves near the sub started dancin' to the beat. Didn't
phase the PB2 a bit, even running at 8db's hot.

Haven't tried Daredevil yet, maybe tonite

 

[steve nn]

I just spent a good hr writing and I lost the whole works in spell check. I am so mad. mmmmmmmmgrrrrrrrrr

I had a great story for you to Tommy. Definitely not going to write it again tonight. DARN!!!!!!

I thought that was basically a 30 hz scene? Great! I get to add 6.5 to 7.5 then. 125-6 db's sound good to me. Should be close to 130 db next week then?

Keith I think you will like Daredevil, well the sound anyway. I liked the story myself and thought it was better than Spiderman.

 

[Tom Vodhanel]

Chuck,

I wanted to give you a quick update.

We got the enclosures, but not until later in the afternoon. We'll work on them over the weekend and have a truckload outgoing on Monday.

Tom V.
SVS

 

[Chip E]

Tom, thanks for my email update as well. Yo guy's, check it out- I email Tom at 1:56am about my PB2+ 2:05am he replies. That's some serious dedication there TV! Thank you...
Looks like Monday for me too

 

[Chuck Watwood]

TomV,

Thanks for the information about my PB2+!!! It will take the sting out of my DVD theft. The guy I'm selling my 20-39PC+ to is as excited as I am. Can you tell me approximately how long it takes to ship that big puppy? I live in Springfield, Missouri. Oh, tell Eric not to forget to add my free T-shirt he said he would ship. XL long please. lol

 

[Jack Gilvey]

I wonder if there's room in the PB2 to tune to 16Hz using two extended ports...that'd be pretty cool.

 

[Chip E]

Jack, i'm pictureing something like Hooker Headers flailing out the back...Lol