You Won't Bleive It (SVS 25-31) (1 Viewer)

[Phil Iturralde]

What is your SVS Volume control level? My SVS 25-31PCi Volume Control = 1/2 (12 o'clock high)

As a FYI: ... here's my Yamaha RX-V1300 final REF Calibration Marks using Dolby Labs DD-EX test tones ...

Volume Control Display = -20.0
LEVEL MENU
- CENTER:... -7.0
- R SUR:....... +2.5
- REAR CT:.. +5.0 (pair wired in-series)
- L SUR:........ +2.5
- SWFR:....... -8.5*

SETUP MENU
- LFE:............ -9*

*I adjusted SWFR by ear playing my digital Jazz Music CD's (David Benoit, Dave Grusin, Diana Krall, etc.) @ above AVG level obtaining a well-balance frequency range. I have not changed the SWFR ... -8.5 level since. It's full, balanced, ... without sounding boomey or bloated. The LFE result is from my REF Calibration Mark using Dolby Labs DD-EX dedicated LFE test tone. The end result is that my Bass support is 100% A-OK when switching between my DD/DTS DVDs Digital LFE bass to my analog bass 2-channel Music CD's (DPL TV shows, VHS tapes, etc.)!!!

I have used the SVS 25-31PCi since April 2002 and after REFERENCE Calibrating my SVS 25-31PCi, ... I experienced impressive tactile sub-sonic 'feel' in the floor, couch, chairs, wall, air and pant-leg(s) (SVS trait) @ all my seating areas when the LFE encoding called for it.

Hope this helps,
Phil

EDIT: SVS 25-31PCi is REF Calibrated (LFE) @ 77 dB (AVG) using Dolby Labs DD-EX dedicated test tone, whereas all the other HT speakers are REF Calibrated @ 75 dB (RS Analog Dial = 70 dB / Weight = C / Speed = SLOW)

 

[ChrisBee]

Trying to judge level without an SPL meter is like trying to drive a car without a speedometer. You think it's easy it until your get pulled over by the AV police.

ChrisBee

 

[Yee-Ming]

FWIW, I have the 25-31PCi, tuned to 22 so its top volume is less than the stock 25-31, but it sure rattles the door and windows in my place. My living/dining room is 26x13x10, with two corridors leading off, but the 25-31 still gives me plenty of oomph. I never listen at reference (apartment living) but if approrpriate can go to -10dB. Never had any problem with insufficient bass.

As a rough test, you should be playing discs like U-571 (depth charges) or SW1:TPM (pod race) -- TPM really rattles everything!

But, as many have already said, nothing can substitute proper calibration.

 

[Edward J M]

He could be sitting in the middle of a gigantic null. Square rooms have a way of doing that. Only way to tell is with a FR sweep at the listening position,

Assuming his BM settings are correct and the sub is gettng all the RB and the LFE channel at full amplitude, maybe he should try near-field placement.

Also, just skimmed the entire thread again and didn't see mention of dynamic limiters. Three things to look for:

1) Dolby Digital Dynamic Compression circuits should be disabled/off. Sometimes referred to as Midnight Mode. Both the DVD player and the AVR will have this circuit.

2) The LFE channel (.1) attenuation control (not to be confused with the subwoofer level control) should be set to its maximum (i.e., un-attenuated) level. This is usually 0 on a scale of 0 to -10.

3) Any bass peak limiter circuit should be disabled or off. This feature is found on THX certified AVRs.

Any of these circuits could kill the bass response and are often responsible for these perplexing "lack of bass" threads.

 

[terence]

I hate to say it but a square room is the worst for acoustics. I have had bad times setting up surround, 2ch in square rooms the worst was a 12x12x9.

 

[BradZ]

I have a follow-up question. I'm thinking about this sub for my 11x15 room and while I want the ability to crank it up and shake the house a bit, I also need the ability to listen at moderate levels at night with sleeping kids upstairs. Is it possible to hold the SVS back and not shake the entire house or blow myself out of the room? Assuming a proper callibration is performed, I want good clean bass without rattling the windows and doors and without knocking my posters askew. Is the SVS the right sub for the job or is it just way too much for such a little room?

 

[Justin Ward]

I think what these guys are saying about square rooms in general is correct. My room is almost perfectly square and the bass response in my room is very uneven. Quite loud, but just not consistent.

 

[GregBe]

Ed's advice is a good one,

You may want to try placing the sub near the listening positon. I was in a similar position with a square room. I originally had my sub up in the corner in front of my room, right next to my front speakers which are about 16' away. Although I had a terrific bottom end, I had huge peaks and dips in frequency response because my room is almost square. I didn't notice this until I watched The Lion King in the home theater mode. On the song, "I just can't wait to be king" I was getting a tremendous bloated boom on each beat. I couldn't even watch it. I ran the bass management frequency sweep on DVE with a SPL meter and found out I had a huge peak around 25 Hz and 60Hz, and tons of nulls in between. I wasn't worried about the 25 Hz because the music I listen to doesn't go that low (I was even thankful for it for movies), but I was very worried about the one at 60Hz
I had read a few threads regarding HSU subs (even though I don't have one) about putting the sub closer to you to get a more even response. I moved my sub directly behind me which is not in a corner, but I more than make up the SPL's with it proximity. What I got was awesome. I still had the peak at 25, but from there on up to the crossover, the needle on the SPL meter barely moved at all. I do get a pretty strong tactile response with very low material, but for music, I cannot locate the sub at all.
Here's the best part of the whole thing for me. I was actually able to lower the output on my sub and get the same SPL reading. This means I can run my sub a little hotter when the family is sleeping than I normally could have previously.

Greg

 

[Rob E]

That is very low, I have the 25-31 in a room(16x12x7) and my gain is set 1/2-3/4,( Most of the time 3/4) and It shakes the whole room let alone rest of the house. My hat goes off to SVS.

 

[Mark Murphy]

My HT is a 12.5 x 12.5 x 8 room w/french doors on one side. I have a 25-31PCi (22hz) and its placed in the left rear corner about 6 feet away from where I sit. I have the gain set to the third line (out of 8) w/the AVR handling the crossover at 100hz. My mains go down to 80hz. The SVS is calibrated w/an SPL meter and the Avia test tones. I couldn't be happier w/the performance of my sub. I was thinking of getting some shakers for the couch before I got my hands on the SVS but I get plenty of tactile response on my couch with the sub alone.

 

[Todd^B]

Radio Shack SPL Meter:

Digital Display Sound Level Meter

Looks like they are out of stock online, but at least you know what you are looking for.

Not a bad price : $49.99

 

[BradZ]

Lee,

did you ever get your sub working to your satisfaction? I hope you got a chance to calibrate the SVS and got the Bass you were looking for.

 

[Lee M T]

I still haven't gotten my meter yet, I hope to do so tomorrow. But I have finally got it sounding to my satisfaction at the time being. I expect it to get even better after I get my meter. But it finally shakes the room and does so accurately. My room is just real weird. I put the sub at my listening position twice and walked and crawled all over the room both times, but I really got hardly any bass response from any location. But, I really only have three real locations I could ever place the sub, so I just stuck it in once placed and played stuff over and over, then moved to the next spot, etc. I finally found a place where it is working quite nice right now. I've been working so much the past couple of days, so I've barely hit the Internet. That is why I haven't updated you guys. I will reevaluate things and post my final thoughts when I get my meter. I can tell though it is going to be a beautiful relationship.

Thanks for thinking about me! :b

 

[Ralph B]

it will be!!!!!

you will see a huge difference once you calibrate. remember to set your phase too. a 80hz test tone while adjusting will do this. from what I remember when I did mine.

 

[Ron Stimpson]

Lee,

It won't be just your sub, but all your speakers, and how they interact with the sub that will be audibly better after careful level setting (calibration) with your trusty SPL meter and a good test disk like Avia.

As you are discovering, room acoustics, good or bad can have a radical effect on any given subwoofer's performance. As you proceed, make darn sure you go thru all your receiver settings one more time before doing the actual adjustments. All speakers to small, NO sound-processing modes (i.e. no "THX Movie" etc), check for any hidden peak/LFE limiters and switch them off (or to their least effective levels)and get familiar with the phase knob too.

Usually phase will have a subtle effect, if any. But in troublesome rooms where cancellation is an issue, small changes to phase can indeed modify what you hear at your chair.

After a basic calibration (it sounds like you would benefit from a 3 to 5dB bump in your sub's level versus your main channels) get some good revealing music or movie passages that you can "loop". Have an assistant turn the phase one hash mark at a time with each run of this loop. Listen carefully for sounds being variously masked or revealed. Looking at your SPL meter to see the peaks you are attaining at the same points of the loop might also be revealing.

If you have trouble getting a loop to run, pick something easy like the main menu for "Godzilla" which has lots of mid/deep bass running in a predictable and self-repeating cycle.

As your ears adjust to the natural, non-boomy SVS bass, and you integrate with that SPL meter (did we mention you need to get one yet?? ;^) I think you'll be more and more pleased with the results.

As always, don't forget you can drop the staff at SVS a note 7 days a week and we'll be on line to assist any way we can.

Take care. Now, run, don't walk to Radio Shack and get that meter. Give plasma if you have to to pay for Avia (receiver test tones are far less reliable as a rule), and you are going a long way to getting the sound right in your room.

Ron

 

[Ralph B]

my room is terrible and adjusting the phase really made a difference for myself. thing was the original spot I out my sub was the best place for it as anywhere else was terrible. even though the place its in now is not the greatest as the room is acoustically challanged.

 

[Lee M T]

Yeah, my room is definitely acoustically challenged. The house is a little over 30 years old and was definitely not built with audio in mind. haha

I was never concerned, I never was like "Oh SVS sucks." I was just a bit flabbergasted. I knew I needed to calibrate and what not, but the results I got when I first fired it up were really dismal. It really should have been doing more than it was. But it has turned out great now. I just had to play with it.

Thanks for the info Ron! I can't wait to get everything just peachy.

 

[Ralph B]

playing with your sub adjusting and calibration is half the fun!!!! I love it and reason I got my 25-31PC+ was being able to tune it like my old Turbo-T!!!!

you learn alot and fun in the process!!!!

when I feel I need a bumb or lowered depending on the source(as DVD-A seems to have more bass than SACD at my calibrated level) I adjust my reciever sub level and when I shut off my reciever goes back to the calibrated memory setting. works for me!