SVS PB1: Initial review

izafar

ATN: Lengthy post

Well I finally got that angry phone call yesterday from wife that UPS has delivered a very big box(so far I have told her that I am getting the smallest of the SVS subs). I tried to calm her down that it must be big on packing; the actual Sub will be small.

After getting home I quickly opened the packing (SVS sure does a good job at packaging), and found out that sub is indeed very BIG. The pics at the SVS’ site doesn’t do it a justice. The finish is very unusual, but at the same time, it gives very solid feel. And this thing is very heavy. I have to drag it on the carpet to its final resting place.

The sub is so BIG that I wasn’t able to put it in the any room corner without moving many other things, so I placed it between the TV and front left speaker. I hooked it up using Radio shack gold series subwoofer cable and Dayton Y cable and set the gain level at 1 Clock position with crossover disabled and phase set to zero.

I then played whatever disc I had in my CD player. This sub sound so much different then my old PSW250, that It took me a while to realize that this one is actually playing. All the boomeeness in the room has gone and I can actually listen to the music at much louder level. The sound was very clean, and whole lot new type of sound that I am still trying to get used to. The next thing I noticed was that this sub sounded somewhat thin in the mid bass area. I was not getting the slam of kick drums with an effect that I was expecting. I then put in the MI2 DVD and watched the TAP dance scene. I am pretty familiar with that scene and often use it for Sub’s midbass response testing. SVS sounded very smooth and clean, but was again little bit weak in the punch.

I initially blame that to calibration, and calibrated the system using Rat shack meter at 85db. I found out that sub was already playing around 10db hot then other channels (0 at AVR and 1 O Clock on sub gain). I calibrated it to 6 db hotter then other channels (-5 on AVR, and 12 O Clock on sub gain). I then watched TAP dance scene again, along with the "Eagles hell freezes over" DTS DVD. I ended up setting the gain up a little between 12 and 1 O click position. By this time the wife and kid were getting impatience from my involvement with the system, so have to take a break from this activity for a couple of hours).

I started again at 10 PM and did the FR sweep on the system. To my worst fears, the -10 db 47HZ dip I had in my room using PSW250 get much worse with SVS, I now have a 15db dip at around 50Hz. And I think that pretty much explains the lack in mid bass response. Looks like I have to do a lot of experimentation with room placement (which would be quite a workout for me next week, considering the weight of this thing).

I am attaching the FR graph bellow. I need help from Doc and other bass heads on the forum to get this thing sound right.

izafar

for comparison purposes, followng is FR of PSW250 in the same room, but the sub was placed 4 foot in the room on the side wall.

Dr. Spec

That is one UGLY dip at 50 Hz. Are you sure this is not electronics vice room modes?

What kind of electronics set-up and bass management are you using?

Second statement - flat to 20 Hz, as advertised. Except for the hole at 50, exceptionally flat in-room response.

Doc

izafar

I have all speakers set to small and crossover on the receiver is set at 80HZ, the crossover on PB1 is disabled. The phase is 0 on sub and it is connected using a Y cable and ratshack gold series sub cable.

Dr. Spec

Originally posted by izafar
I have all speakers set to small and crossover on the receiver is set at 80HZ, the crossover on PB1 is disabled. The phase is 0 on sub and it is connected using a Y cable and ratshack gold series sub cable.

All sounds good - definitely a room induced null.

First see how big the null is. Move the SPL meter in a few different spots and run that 50 Hz tone and see how wide/deep the null is. If the null is tiny, you might be able to work around it. If it is huge, then moving the sub is your only choice.

http://www.guidetohometheater.com/shownews.cgi?388 This link might help with room acoustics.

If the null is large, start hauling that sucker around and try some bizarre locations and you might find one that works perfectly. Subs and real estate have three things in common: location, location, location.

Without seeing it, I'd bet this is a near square room?

Doc

faster100

hey spec can you tell me again how to do the 1/12 fr sweep for my sub, ?? I got the cd burned right finally and want to do the sweep for my room,

Sorry for the derail guys

Dr. Spec

Just run the sweep and record the SPL on C-weighted slow at each frequency. Don't play above 75-80 Hz or you will fry the VC of the woof. Keep the meter at the listening position on a tripod or other stable surface.

Add the RS Correction Factor to each value, and plot it in Excel.

I have all of this stuff done if you want the spreadhsheet.

Doc

faster100

I have your spread sheet,, see my post in subwoofer hookup

VR3

This sub is what I am looking at, I plan to buy one - then sell the M&K, and my CS245i, and buy another one. Hahaha, that should be a kicker. So my front sound stage would be CSi40, RT35i, and Dual Pb1's...lol. Hows that sound? Whoah man, talk about a DIP. LoL, thats probally what is wrong with my subwoofer......@_@

izafar

I moved the sub to the corner last night and immediately noticed a slight increase in bass response. I then did the FR Sweep again. The NULL is still there but it has moved from 50HZ to 45HZ. I then take reading around my seating area at 45HZ and found out that null exists in area of 2 feet on both front and back of the seating area, i-e it is fine if I move the chair either two feet back, or two feet forward. I have to do this experiment again from the previous position; meanwhile I will try it in the corner till the weekend.

Following is the layout of the room with both the sub positions that I have tried so far:

goingganzo

can you try the other corner with the long wall? and the olny other way ti fix is with eq or bfd. try putting the sub where you sit and serch for where there is no null along the wall this might work?

Dr. Spec

Tough to fix nulls, even with a BFD or PE. Keep experimenting with location and only use the BFD as a last resort. Nice diagram, BTW.

Doc

izafar

I will try the other corner this weekend. The issue with that corner is that the first 10 feet of the long wall consist of glass window, and I suspect that placing sub in that corner will vibrate it a lot.

Last night was my first real movie experience with this sub. We were watching Harry Potter COS. As there is no boominess/distortion with this sub, I was watching it about 5 db higher than my normal listening levels; also the sub was calibrated around 8db higher than other speakers. The first explosive scene in the movie is when little wisely goes to Diagon Ally. The impact of this explosion was so powerful and comes with such a surprise that I almost fell off the couch. I think something similar must have happened with the neighbors in upstairs apartment as it triggered a lot of frenzy movements (which can be heard at my place).

Needless to say that I have to recalibrate the sub to only 3 db hotter and turned the overall volume down to normal listening levels.

Doc:
Do you know what would be the effect of changing distance setting of the subwoofer in the receiver? I remember that I once read about it in an online article, which suggested that distance settings for a sub affectively changes the phase and can be used to getter in-room response.

goingganzo

all the distance will do is cange the delay and make the sub out of sinc with the rest of the sound.

Dr. Spec

Originally posted by izafar
Last night was my first real movie experience with this sub. We were watching Harry Potter COS. As there is no boominess/distortion with this sub.

The first explosive scene in the movie is when little wisely goes to Diagon Ally. The impact of this explosion was so powerful and comes with such a surprise that I almost fell off the couch.

Needless to say that I have to recalibrate the sub to only 3 db hotter and turned the overall volume down to normal listening levels.

Told ya............:D Clean, deep, powerful = SVS.

HP-COS is a very nice DVD for bass - impressive DD-EX track.

Everyone runs their new SVS really hot for a short while, and then you'll come around and calibrate it about 3 dB hot and really come to enjoy a perfect balance of slightly aggressive bass that still blends perfectly and doesn't overshadow the rest of the sound track.

Bryan is right, the distance function is the same as for any speaker - time delay. Just alter that whenever you move the sub around.

Doc

goingganzo

so doc i bet you are realey looking twards your pb2 you will have the same promlem that i do. your mains wont keep up with the output of your sub. whell that was befor i got the new adcom. i wonder if it is the same way now. that pb2 is about 200 more than i spent on the strikeforce

Dr. Spec

Originally posted by goingganzo
so doc i bet you are realey looking twards your pb2 you will have the same promlem that i do. your mains wont keep up with the output of your sub. whell that was befor i got the new adcom. i wonder if it is the same way now. that pb2 is about 200 more than i spent on the strikeforce

The 3803 has so much power and volume with the speaks set to small that the sub is the limiting factor right now.

I have never bottomed the PC+, but it has limits and I doubt (and so does SVS) it can safely hit Reference Level in my room.

The PC+ is worth 113-114 dB peaks on c-weighted fast in my room, and I'm about 5-6 dB shy of Reference on most DVDs, and the PB2+ will give me the headroom I need to not worry about overstressing the sub.

Doc

faster100

Tom over at SVS told me this about my room and the pb1

Hi Cliff,



The 20-39PCi and the PB-1 will perform nearly identically from about 22-23hz and up…under that and the 20-39PCi will have a very slight edge.



In your room, both of these options will extend down to the 16-18hz range, providing a clean 112-118dBs of output.(very low and very loud).

Tom V.
SVS

TonyPTX

Originally posted by Dr. Spec
Add the RS Correction Factor to each value, and plot it in Excel.

I have all of this stuff done if you want the spreadhsheet.

Doc

Doc, I'll take your spreadsheet. Email to: TonyPTX@cox.net

Thnkx

PS. do the rat shack correction factors work for the digital and the analog versions?

Dr. Spec

Originally posted by TonyPTX
Doc, I'll take your spreadsheet. Email to: TonyPTX@cox.net

Thnkx

PS. do the rat shack correction factors work for the digital and the analog versions?

Hi Tony:

I'll send you my spreadsheet for the 20-39PC+, but do not use the correction factors in that spreadsheet - they are unique to my SPL meter.

Instead go here for the RS Correction Factors and just interpolate for values inbetween on the spreadsheet. And yes, the CFs will work for both analog and digi meters.

http://www.hometheaterhifi.com/utilities-download-page.html


Doc

TonyPTX

Pleasure as always....Thnx Doc