Calibration complete

[karkus30]

Took me the best part of 6 hours though. The BFD was the dogs danglies. Now I have a nice graph starting around 18Hz @ 87db right down to 80Hz @ 76 db couple of bumps at around 60Hz but only a couple of db out.

The acid test is trying a film. But the graph tells me its definitely going to be an improvement. I can now talk with confidence on the subject of Ultra / BFD calibration.

[Smurfin]

umm, what exactly does the graph look like? Your response @ 18hz is +11db over that @ 80hz?

[Daneel]

I know a lot of people recommend a "house curve" (higher output as the frequency drops) but 11 dB sounds a bit much. Still, as long as it sounds good!

With the Ultra I'm really hoping that between placement, phase control and PEQ I can get by without a BFD. Apart from anything else, there's nowhere to put that damn thing!

[ShinObiWAN]

House curves are brilliant for HT in my opinion but less desirable for music.

To the that effect I have two BFD setting which are geared towards each.

Regarding the +11dB gradient on the frequency plot, its almost exactly what I use and I find it perfect for really creating some awesomely deep effects on movies.

[karkus30]

Just to try and answer all those points !

The graph is a nice undulating line, dropping smoothly down to the crossover point at 80Hz.

In my room, the original graph had a peak of around 5db @20Hz, huge peak @ 31.5Hz of around 12db and began to get into serious decline @40Hz by 56Hz it was -20db !

This was exactly how it sounded during a film. Essentialy, once the Xover frequency was reached the lower mid range collapsed until really low bass effects kicked in at around 40Hz.

I can really see how I can improve on these results as the graph is fairly flat, it would mean a serious cut throughout the 18Hz to 40Hz level, which would no doubt completely scew up the curve.

I only use this system for films.

The acid test is still to come. After 6hrs I was loosing the will to live, so putting a film on , didnt appeal.

[Smurfin]

Originally Posted by karkus30

After 6hrs I was loosing the will to live, so putting a film on , didnt appeal.

I know what you mean....it's good fun but it gets to the point where you just think.....oh please let me get it right this time

re: the +11db variance, of course if it DOES sound good in your room then that's all that matters, however in my own experience a difference of that much simply results in overblown bass, and movies with seriously low bass just get fatigueing. Having ANY frequency +11db over others is something I'd DEFINATELY be trying to tame. Just imho of course

[karkus30]

Originally Posted by Smurfin

I know what you mean....it's good fun but it gets to the point where you just think.....oh please let me get it right this time

re: the +11db variance, of course if it DOES sound good in your room then that's all that matters, however in my own experience a difference of that much simply results in overblown bass, and movies with seriously low bass just get fatigueing. Having ANY frequency +11db over others is something I'd DEFINATELY be trying to tame. Just imho of course

Considering the difference was about 30db originally

until around 50Hz its more or less flat (within a 1 or 2db) at 56db there is a slight dip of around 5db. Infact, why dont I just give you the figures and you can plug em into worksheets.

FREQ RAW SPL
16 64
18 78
20 79
22 79
25 78
28 80
31.5 82
36 80
40 81
45 82
50 82
56 78
63 80
71 75
80 74
89 56
100 60
111 54
125 58
142.5 62
160 60

Tell me if you think I can improve, bearing in mind I have 9 filters set. 1-6 are cutting freq up to 49Hz by around -4-6db and the rest are boosting between 50Hz and 63Hz by up to +10db.

Boosting frequencies seems to have a bad effect on the graph.

Now you know why I did'nt fall over myself applauding the SVS Ultra Its not the subs fault, but I do think a sub which handled the 100Hz down to 40Hz would have been a better investment. Maybe a second sub that just looked after the below 40Hz signals ! But intergrating that lot would be a nightmare.

Its one of the reasons I use a different system for music. My Full range floorstanders manage 20Hz(a few db down) and the response is pretty flat from around 25Hz up to 20Khz.

[Ian J]

Spreadsheet attached

[karkus30]

I knew there was a way to do that. I still dont seem to be able to attach thumbnails etc. Comments ?

[Ian J]

I assume that your main speakers were disconnected when you took the readings. I wonder if you had them switched on and were crossing over at 80 Hz whether the overall response would be smoother at that sort of level

[karkus30]

Originally Posted by Ian J

I assume that your main speakers were disconnected when you took the readings. I wonder if you had them switched on and were crossing over at 80 Hz whether the overall response would be smoother at that sort of level

Im not keen on disconnecting speakers from a working amplifier, so they were just turned down as low as possible and turned speaker face down on the floor.

I tried the 'escape from earth' scene from Titan AE. The vocals are much clearer and the impacts are more defined, so its definitely better. I have the sw output at -7db and the BFD just clips on the very noisy bits. The sub has the gain set to about the 1/3rd mark. Theres still a bit of intrusive rumble (probably around the 20Hz mark), but thats more a volume thing exciting the room.

[BAN5HEE]

Stupid question but where the hell do you go to do all these settings? Is it on your amp or where casue I sure ass hell cant change any of those things apart from on my sub.

[karkus30]

Most is on a thing called a Behringer feedback destroyer, which has a built in 12 channel parametric equaliser. Its kit thats meant for the pro musician, but can double as an equaliser for home cinema.

You need a bit of kit to measure the sound levels called an SPL meter and a disc full of frequencies which you can download from a website called snapbug. All this get put onto Microsoft worksheets and thats what the graph is.

[Ettepet]

Originally Posted by karkus30

In my room, the original graph had a peak of around 5db @20Hz, huge peak @ 31.5Hz of around 12db and began to get into serious decline @40Hz by 56Hz it was -20db !

I hope you didn't use heavy amplification of certain frequencies, as this is highly discouraged. The sound-quality of these frequencies is terrible in general, which you can easily check. It might even damage your subs Amp at high SPL, during an unfortunate concentrated (sound-effect) burst in that frequency region.

You should either ignore these (hopefully) insignificant regions, or place the subwoofer in a better location. I use small amplification in certain frequency regions myself, but only by 4 or 5 dB, and with that I do have a completely flat FR between 16-70Hz. B.t.w.: my room is in no way ideal soundwise, in case you wondered.

[karkus30]

Originally Posted by Ettepet

I hope you didn't use heavy amplification of certain frequencies, as this is highly discouraged. The sound-quality of these frequencies is terrible in general, which you can easily check. It might even damage your subs Amp at high SPL, during an unfortunate concentrated (sound-effect) burst in that frequency region.

You should either ignore these (hopefully) insignificant regions, or place the subwoofer in a better location. I use small amplification in certain frequency regions myself, but only by 4 or 5 dB, and with that I do have a completely flat FR between 16-70Hz. B.t.w.: my room is in no way ideal soundwise, in case you wondered.

Ettepet, Im not really sure what your saying ?? I use the amplification I have and the graph shows the db levels. This is the accepted way of setting up a sub woofer. Tried moving the location, but it just wasnt happening. The room that I use at present has terrible acoustics as its square.