New PC13 Ultra and SMS-1 tuning advice pls

[Baxtor]

Hi all, finally bit the bullet and upgraded my subwoofer from a Rel Q200E to a PC13 Ultra, also purchased a SMS-1 to go with it.
I have done what I can with it, but would appreciate it if you guys could look it over and see what you think.
The room is fairly small, measuring about 6m x 3m x 3m
As for postioning the sub is in the only place possible, so moving it is not an option
The 1st image is without any EQ, the 2nd is what I came up with and 3rd is settings.

[recruit]

Hi Baxtor, very nice sub indeed and good combination with the SMS-1

I would say a good attempt ref to EQ'ing but is the sub in it's best position in the room ? as from what I can see you are trying to boost frequencies around 32hz with little effect, which is more than likely a null which should not be boosted, I would try some different locations if at all possible for the flattest response without EQ and then make some minor adjustments with the SMS to smooth it out...also make sure all the settings on the sub are correct ie PEQ is off / Xover off / and what frequency the sub is tuned to ?

[marc carballo]

if i can butt into your post i have a pc13u and i would be intrested to know if your sub sounds better with your sms1 as im intrested in buying a used one soon

[Richard Torble]

Originally Posted by marc carballo

if i can butt into your post i have a pc13u and i would be intrested to know if your sub sounds better with your sms1 as im intrested in buying a used one soon

Looking at those graphs, it looks like it sounds a lot better with the SMS-01. The same results however may be achievable with careful positioning and the PEQ on board the sub. Unless you are using these in conjuction with REW, there's no visual feedback however.

[Isco 3]

You have done some good work there.
It does seem a bit louder than normal though. But much smoother.

[russ.will]

Looking at those graphs one thing immediately strikes me and that's you're boosting the dips in the response. Whilst I wouldn't quibble about 2dB or so here and there as long as it's above port tuning, in the case of your 35Hz(ish) dip, you're using two closely spaced and almost certainly overlapping filters boosting at 6dB each.

This is not good.

That dip and the lesser example at 75Hz(ish) are cancellations and there's one of three reasons for them being there.

One is positioning of the sub and/or yourself in which case one of you is going to have to move some. I don't think it's this one though, because boosting a room/positioning induced dip is self defeating and you've clearly managed to boost the dip.

The second is that you have an opening into another room and it's resonances are causing cancellations in the main room - Not a lot you can do about this if there's no door to close. I'm not sure it's this either as I think the effect would be the same as above.

The third is phase related between your speakers and the sub. Assuming you (or your amp if it has an auto setup routine) has set the distances to the speakers/sub correctly, you need to play with the phase and polarity controls on the SMS-1 to see if they are cancellations caused by speaker interactions. Try each phase step by step (in +ve and -ve polarity) before even touching the PEQ filters. I would also apply the phase adjustments in the global/setup column as once set they will apply to all other presets regardless.

You want to do everything you can to smooth the response without using the filters as they treat the symptom rather than the cause. Less is always more, with respect to EQ.

Next, I would set the subsonic frequency to 6Hz - The SVS has a high pass filter of it's own, so it doesn't need the SMS-1 duplicating the effort. If yours doesn't go lower than 15Hz, then you need to go to the Velodyne website and download the v2.1.3 firmware which enables a high pass down to 6Hz and sorts a few other issues.

Russell

[Baxtor]

Wow thx guys, some good stuff there
There is no opening to another room, unfortunatly I think it is the postioning of the sub, which is at the side of the sofa at the back of the room.
I was worried about the boosts as well, will go and try some of the things suggested and report back

[Baxtor]

Ok had another go at it, after much moving of stuff found another spot for the sub, and this is what I came up with this time.
Not so much boosting needed but a few dips in the higher freq's.
Would you take this over the last try?

[russ.will]

That's much more like it.

Have you played with the phase to try sorting out the dip? The trick is to mute the sub using the SMS-1 remote to see what the speakers response looks like alone. If un-muting the sub creates a dip where there previously was none, then you have a phase issue. This can occur regardless of where the sub is, but remember to reset your subs distance if you move it - Distance and phase are closely related.

Russell

[Baxtor]

Just tested out with the sub muted and it makes no difference

[Mr Incredible]

Originally Posted by russ.will

That dip and the lesser example at 75Hz(ish) are cancellations and there's one of three reasons for them being there.
.........


Russell

Could I be bold to suggest another reason for the dip......

The speaker response from the graph, together with the stated response of the speakers (76Hz), and a crossover of 80Hz may be leaving too much of a hole around an 80 Hz crossover. What crossover are you using?

[Baxtor]

80Hz

[Mr Incredible]

Typically as a rule of thumb the crossover should be an octave (read twice the frequency) of the -3db point of the frequency response of your main speakers.

For reasonable bookshelf or floor standers, a XO of 80Hz is not unreasonable. But with your Gallo A'Diva only mustering down to 76Hz at -3db, you really need to supplement that with a bit more from the sub by increasing the XO. THe downside is that too a high a XO and you can start "locating" the frequencies at 100Hz. Some people can locate 80Hz as well, but I'm not one of them!

Just as a long shot, try a 100Hz Crossover.

[russ.will]

Originally Posted by Mr Incredible

Could I be bold to suggest another reason for the dip......

The speaker response from the graph, together with the stated response of the speakers (76Hz), and a crossover of 80Hz may be leaving too much of a hole around an 80 Hz crossover. What crossover are you using?

Good spot. I was getting the A'divas confused with the much larger Reference 3s.

I'll get me coat.

Russell

[Baxtor]

Ok this is with crossover set at 100
Would you suggest I stick with that?