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# Official SVS Owners/Support Thread. - Page 396

Quote:
Originally Posted by brian6751

I set each sub to around 72db using their gain knob with the sub trim at 0. Then set them together to 75 using the sub trim

Here is the thing that does not make since to me. It seems like if you set EACH subwoofer to 75dB with the sub trim level from the receiver set to 0dB, wouldn't you get more power or the maximum power from both subs?

I mean, why set BOTH subs to 75dB when you can get more maximum power coming out of BOTH subs. If each sub is putting out 75dB, and you set the other sub at 75dB, you would get the DOUBLE power from both subs.

### Gear mentioned in this thread:

Quote:
Originally Posted by steve nn

I have always thought that but that might be a general statement?? It seems I came across a post by Bill F stating at certain freq it can actually be more. Now I’m not saying it can be by any measure, but it does seem Bill posted that correcting me, or someone else once?? I don’t know the physics involved.

Well if you get more than a 6 dB increase at a particular frequency when playing a second sub, I guess this is likely due to a room resonance or room gain amplifying it. All I'm saying is that if you take a wave form and double its amplitude then 20*log(2) = 6.02 dB. Pure maths, no physics involved
Quote:
Originally Posted by mantaraydesign

Quick question about setting up the Dual subwoofers.

I am using the SPL sound meter for measurement. Do you set EACH subwoofer to 75dB or BOTH subwoofer together at 75dB?

The goal is to have both together playing at 75 dB.
Quote:
Right now, the Volume on the subwoofer is -16dB for the LEFT and RIGHT subwoofer. Then I use the SPL sound meter to set BOTH subs at 75dB with the Volume Sub Level with the receiver.

Or should I set the subwoofer Volume on BOTH subs to 0dB, and then set the Volume Sub Level on the receiver to 75dB?

What you did is okay.

However if you want to squeeze the maximum dynamic range of the amp, as per Ed's recommendations, then each sub should be set to 0 dB, and the sub level on the receiver should be reduced accordingly. However you likely won't be able to do that since you'd have to lower the sub level on the receiver by about 16 + ~3-6 dB so around 20 dB less. It may not be possible on your receiver, or if possible probably not advisable as it's a good idea to leave the AVR level close to 0 dB. Moreover, if you reduce the AVR level a lot, the signal coming out of the AVR will be so low that it will take higher volumes to turn the subs on automatically.

In my setup I can't set the dual subs at 0 dB either or else I have to raise the main volume to about -35 dB for the subs to turn on, whereas I do plenty of listening in the -40 to -50 dB range. Using -10 dB on each sub allows them to turn on around -55 dB main volume depending on the content.
Quote:

Yeah. Well if you're not confused enough, consider this. By setting your subs to the same gain, they work equally hard. But unless they contribute exactly the same to what is perceived at the listening position (which is unlikely -- in my room my two subs are symmetrically positioned but one contributes about 4 dB more than the other), then one sub will be heard more than the other. It's not much of a problem and it's one way of doing things (the subs are gain-matched and work equally hard).

The other way to do things is the *level-match* the subs, i.e. ensuring that they each contribute equally at the listening position. However this will likely mean that one sub will work harder than the other. Level-matching the subs so that they contribute equally, while also ensuring that they reach 75 dB together, is a bit more complicated. I did it more easily in my setup using the MiniDSP which allows you to adjust input and output levels on the fly.

EDIT: Brian's advice is spot on.
Quote:
I guess this is likely due to a room resonance

In thinking about this last night that was the conclusion I came to if indeed that’s what he stated? Regardless it’s a little nit picky thing anyway.
Now I need to tune my svs pb12+ , the issue is a square room , should I do 16hz tune ?
If you're not pushing it to it's absolute limits and need to squeeze every last dB out of the 20 Hz tune ( which has a bit more output), then by all means try the 16 Hz tune. Many people here (me included) use it. Don't forget to set the amp accordingly, though I'm not sure there's such a setting on the BASH amp.
Quote:
Originally Posted by dave00gt

the issue is a square room

Try to make sure that the distance between the sub and each of the four walls is different, that the distances between opposite walls are not small multiples of the other (e.g sub in the middle or 1/3 along) and keep it out of the corners unless you want huge peaks at the resonant frequencies.

The usual advice and caveats on multiple subs, placement, room treatments and risers applies.
Quote:
should I do 16hz tune ?

Depends on your requirements and listening material, but in any case try both with proper receiver calibration after each change and see which sounds best to you.
Quote:
Originally Posted by neutro

If you're not pushing it to it's absolute limits and need to squeeze every last dB out of the 20 Hz tune ( which has a bit more output), then by all means try the 16 Hz tune. Many people here (me included) use it. Don't forget to set the amp accordingly, though I'm not sure there's such a setting on the BASH amp.
Yes it does have the 16hz option and I have plugged in a single port out of 3
Quote:
Originally Posted by AJCxZ0

Try to make sure that the distance between the sub and each of the four walls is different, that the distances between opposite walls are not small multiples of the other (e.g sub in the middle or 1/3 along) and keep it out of the corners unless you want huge peaks at the resonant frequencies.

The usual advice and caveats on multiple subs, placement, room treatments and risers applies.
Depends on your requirements and listening material, but in any case try both with proper receiver calibration after each change and see which sounds best to you.
Thx I may need to buy a longer sub cable and see how I will hide it
I have the sub in a corner and I did the crawl test but of course the sub sounds better on the opposite corner , does that mean put the sub there prolly not
Guys you might like to see the recent installation we did at home with four SVS SB13-Ultras in my home cinema in Auckland, New Zealand.

We built a new stage to house four SB13-Ultras (in pairs) at 1/4 points from the side walls.
My only regret was having no space in the rear of the cinema for another four.

We had to use a very limited space behind the back row of seats so cutting into the wall allowed us to install four thin 10" passive Velodyne Subs.

The bass in the room with eight subs is "Out of this World"

If you are interested you can read the about the install here....
http://www.rapalloav.co.nz/blog/SVS-THUNDERS-SHAKES-THE-GROUND-IN-9.8-DEVONPORT-CINEMA/
Hi

I'm using a SVS PC12-NDS with Onkyo 818 with Audyssey XT32. Having gain problems on the sub when calibrating. If I use 75dB to what the Onkyo mic is registrering the gain have to be almost at 0. If it's at 9-12 o´clock that usually is wanted, Onkyo is registrering way to high. Heard there may be SVS+Onkyo problems since I read many people have similar problems. I don't own a real SPL meter, I could use the iPhone5 as extra if needed. Any suggestions?

Is it to continue using 75dB and just raise the channel level of the sub so the calibration isn't comprimised. Or should try this:

1. Make sure Audyssey is disengaged or off.
3. Plug in the included Audyssey microphone.
4. Audyssey's on-screen instructions will pop up. One of the initial requests is that you set your subwoofer volume to 75dB. You've done this with your SPL meter so go ahead and click next even if the Audyssey microphone is saying your subwoofer's volume is different than 75dB. Ignore it.
5. Complete the various steps to finish the Audyssey setup procedure.

When Audyssey shows you its findings I'm willing to bet your subwoofer's placement and dB setting will seem more accurate.

Aren't one crippling the SVS way to much if the gain is almost at the bottom?

Heard running the subs hot from the beginning doesn't really matter since the Audyssey will flatten it with the calibration.
Edited by wesslan1 - 10/11/13 at 4:52am
Quote:
Originally Posted by dave00gt

I have the sub in a corner and I did the crawl test but of course the sub sounds better on the opposite corner , does that mean put the sub there prolly not

Why not? If it sounds better... Well of course there are other considerations but sounding better is a major one I'd say
Quote:
Originally Posted by RapalloAV

Guys you might like to see the recent installation we did at home with four SVS SB13-Ultras in my home cinema in Auckland, New Zealand.

That is a *seriously* awesome setup Rapallo. Congrats! I have a few questions though. Aren't the Velodynes the limiting factor in this setup? I.e. can they keep up with the four Ultras? Also, don't you feel four stage of EQing is a bit much and would introduce phase issues between the various filters involved? Do you have a frequency response measurement?
Quote:
The bass in the room with eight subs is "Out of this World"

That I can believe
Quote:
Originally Posted by neutro

Aren't the Velodynes the limiting factor in this setup? I.e. can they keep up with the four Ultras? Also, don't you feel four stage of EQing is a bit much and would introduce phase issues between the various filters involved? Do you have a frequency response measurement?
One would think the Velodynes would be the limiting factor especially me, but I suppose there is so much headroom on the room nothing seems to be limited at all. I can sit in the back row of seats with the Velodynes under me but I don't know they are there, I cant even hear them. At times I have to get on the floor to feel if they are even working, but they are. All the bass in the room seems to come from the front where the screen is so I feel its integrated well. All the eight subs total Audysseys 75db, it is huge in the room and at times I feel should I run less! There is NO need to run any of the subs hot.

I originally just had two 12" Velodynes in the front of the cinema which sounded good, but after more study I knew I needed to go four subs to address the room modes after using REW. Even with the four SB13s up front alone the bass was great, but after experimenting with placement in the back row REW showed me that the results were better in the room, plus it also sounded better to us.

I have recently removed the Antimode as I know that it is no longer needed since a lot of room acoustics had also been addressed lately, less inline to deal with is better if not needed. We are only relying now on Audyssey to addressing the EQ. But advice was taken from Bob at Velodyne to auto EQ the two SC-1250 amps first, then manually EQ the SMS-1 so at least the Velodynes are taken care of to some degree, then finally XT-32 addressing all 8 subs in the room. The measurements I have were taken before all this was addressed, but experiment measurements were done before the stage and back wall was cut up to house the subs. We spent about six months getting the subs to this stage.
Well congrats, the results are impressive! Are you trying to use excess headroom to equalize flat to a lower frequency (i.e. gain extension)? Or does room gain just pick up the slow cut-off of the sealed Ultras and basically give you plenty of extension that way?

As for the time setting up all this... It took me months just to be pleased with two subs so I can understand what you're saying
Quote:
Originally Posted by neutro

Well congrats, the results are impressive! Are you trying to use excess headroom to equalize flat to a lower frequency (i.e. gain extension)? Or does room gain just pick up the slow cut-off of the sealed Ultras and basically give you plenty of extension that way?

As for the time setting up all this... It took me months just to be pleased with two subs so I can understand what you're saying

Gee Im really not sure how to answer the first part of the question I just don't know sorry.
As for the time involved getting to this point it has been terribly exhausting and time consuming, I really don't want to go through it all again!
If I was planning a room from scratch again it would be so much easier, I have learnt a lot through mistakes I made when I built the room.
Sometimes we have limiting factors and then we just have to work with those.
If I could have used just two SB13s up front and two in the rear it would have been so much easier. Mixing subs of different brands is certainly a challenge and not something I would suggest unless one has plenty of time and patience.

My biggest limiting factor was the back row of seats up against the wall, as you know this is terrible!
The bass in that row was a shocker, with the subs located there now the bass is great and some prefer that row the best!
Strange how things end up.....
I'm the one being sorry... Just an attempt at explaining the idea in a better way. When you have headroom to spare, one way to "spend" it is to boost the very low frequencies using EQing. Of course EQing can't make you go over the maximum output of the sub at a given frequency. But if you listen below max output, then you have some room to EQ. With a sealed sub and lots of headroom, one can certainly get a few Hz of extension by boosting the very low frequencies.

I attempted this when I had a single SB12 but the amp's DSP already does this and thus headroom was much smaller than I thought. Now I have ported subs (dual PC12-Plus) and one way to do the same trade-off is to tune the subs lower. The 16 Hz tune offers less output (at 20 Hz) than the 20 Hz tune but it extends the roll-off quite a bit. Since the dual Pluses have massively more output than I need, the 16 Hz tune was a no-brainer.

I know what you mean with a row so close to the wall. Bass is most often uncontrolled and very loud near boundaries. Trying to provide adequate and balanced bass for 12 seats might indeed be a challenge. In my diminutive living room, there's only 2-3 adequate listening positions!

EDIT: I counted the seats more carefully.
Quote:
Originally Posted by neutro

I'm the one being sorry... Just an attempt at explaining the idea in a better way. When you have headroom to spare, one way to "spend" it is to boost the very low frequencies using EQing. Of course EQing can't make you go over the maximum output of the sub at a given frequency. But if you listen below max output, then you have some room to EQ. With a sealed sub and lots of headroom, one can certainly get a few Hz of extension by boosting the very low frequencies.

I attempted this when I had a single SB12 but the amp's DSP already does this and thus headroom was much smaller than I thought. Now I have ported subs (dual PC12-Plus) and one way to do the same trade-off is to tune the subs lower. The 16 Hz tune offers less output (at 20 Hz) than the 20 Hz tune but it extends the roll-off quite a bit. Since the dual Pluses have massively more output than I need, the 16 Hz tune was a no-brainer.

I know what you mean with a row so close to the wall. Bass is most often uncontrolled and very loud near boundaries. Trying to provide adequate and balanced bass for 12 seats might indeed be a challenge. In my diminutive living room, there's only 2-3 adequate listening positions!

EDIT: I counted the seats more carefully.

This is a better image of the room with the three rows of seating.

The four SB13-Ultras are down the front under the stage and the four passive 10" Velodynes are behind the back row of seating. I would never build a room with the back row of seats up against the wall like this again but its too difficult to change now with the risers built into the room. The rear subs though have balanced the room and removed the BLOATED boom at the back wall. The whole back wall today is coved with 6" thick compressed fiberglass with a 2" air gap in behind. A lot of room treatments have also been installed to stop reflections, all this has contributed to beautiful sounding bass.

Below is an image of the foyer, projector JVC X95 is housed above the rack area.

been searching this thread and looking online, but can't decide. Going to order either SB12 or PC12, but can't decide. approx 3200 cu ft. room open to kitchen/dining area. Wife doesn't care either way. looks not a big deal. need small footprint, so PB12 isn't an option. 80/20 movies/music. Absolutely can't go over \$700 budget for sub (priorities are my 3 little kids and wife being a full time student).

thanks
^^^ I would strongly suggest the PC12-NSD then.
Quote:
Originally Posted by Norske

Going to order either SB12 or PC12, but can't decide. approx 3200 cu ft. room open to kitchen/dining area. ... need small footprint ... 80/20 movies/music. Advice please. Want to order ASAP ... Absolutely can't go over \$700 budget

You want the ported cylinder. There are two current PC12s: the PC12-PLUS and the PC12-NSD and the only one under \$700 is the PC12-NSD.

Given your budget, you might want to consider buying used and get either a bigger sub or two subs. My two SB-1000s cost under \$700 for both, for example.
Edited by AJCxZ0 - 10/12/13 at 9:08pm
SVS nation!!! looking for some advice here....

In my movie room (2800 cubic foot), I currently have 3-subs (2 VTF3-HO's + 1 VTF3 MK4). Downstairs in my living room, I had dual vtf3-mk2's (which I just sold...). So, I am moving 2 of my subs from my movie room downstairs to my living room system.

I am looking to buy 2 subwoofers (most likely... ) OR, keep the dual VTF3-HO upstairs and move the VTF3-MK4 downstairs....

So...

Should I get dual PB13-Ultras (to pair with the vtf3-mk4, moving the dual VTF3-HO's downstairs...), OR 2 VTF-15H's

Or buy just 1 PB13-Ultra and pair it with the dual VTF3-HO's in the movie room?

-Luis
Quote:
Originally Posted by Norske

been searching this thread and looking online, but can't decide. Going to order either SB12 or PC12, but can't decide. approx 3200 cu ft. room open to kitchen/dining area. Wife doesn't care either way. looks not a big deal. need small footprint, so PB12 isn't an option. 80/20 movies/music. Absolutely can't go over \$700 budget for sub (priorities are my 3 little kids and wife being a full time student).

thanks

I have a sb12-nsd in a 2000 cu ft room and it does a great job better than the pb1000 I had. With your room being larger and open and your use mainly movies I would go with the PC12.
Quote:
Originally Posted by Norske

been searching this thread and looking online, but can't decide. Going to order either SB12 or PC12, but can't decide. approx 3200 cu ft. room open to kitchen/dining area. Wife doesn't care either way. looks not a big deal. need small footprint, so PB12 isn't an option. 80/20 movies/music. Absolutely can't go over \$700 budget for sub (priorities are my 3 little kids and wife being a full time student).

thanks

+1 on the PC12-NSD. Ours brings a whole new dimension to our movies.
something must be wrong with SVS website, tried to register and purchase a PC12-nsd, but it wouldn't work. I know for certain all my info was correct but it wouldn't go through. I'll call them and do it over phone. I appreciate the input everyone. Home theater just isn't the same since my sub died last weekend.
They might be updating??
Quote:
Home theater just isn't the same since my sub died last weekend.

I would think not. Congrats!
Quote:
Originally Posted by Norske

something must be wrong with SVS website, tried to register and purchase a PC12-nsd, but it wouldn't work. I know for certain all my info was correct but it wouldn't go through. I'll call them and do it over phone. I appreciate the input everyone. Home theater just isn't the same since my sub died last weekend.

You should buy it from AV science. They have great prices and are an authorized dealer. Just bought my PB13 Ultra from them about 2 weeks ago.
Quote:
Originally Posted by Norske

something must be wrong with SVS website, tried to register and purchase a PC12-nsd, but it wouldn't work. I know for certain all my info was correct but it wouldn't go through. I'll call them and do it over phone. I appreciate the input everyone. Home theater just isn't the same since my sub died last weekend.

I'm tempted to sign on and buy a second PC12 just to see if you are right about the site, but from the standpoint of marital harmony that wouldn't be prudent.
I am wondering if anyone can help me.
I have a 20-39PC plus that just stopped working. Watched a movie earlier, shut everything off went to the store.
Came back turned everything on and no bass.
The green light comes on and the fuse is in tact so I don't think the amp is fried
I switched to a spare velodyne I have and it worked so its not the denon AVR.
Does anyone have any ideas?
Quote:
Originally Posted by jfreeman420

I am wondering if anyone can help me.
I have a 20-39PC plus that just stopped working. Watched a movie earlier, shut everything off went to the store.
Came back turned everything on and no bass.
The green light comes on and the fuse is in tact so I don't think the amp is fried
I switched to a spare velodyne I have and it worked so its not the denon AVR.
Does anyone have any ideas?