How many of you are using the subwoofer distance that Auto-Cal provides?

[Kingdaddy]

I thought I would start a separate thread on this subject as I’ve seen a lot of questioning about many processors that have the Auto-Calibrate feature, not just the Halo. Most are questioning the accuracy and manually inserting the measurement based on a physical measurement, because the auto-cal gives a much longer distance then what is physically measured.

However, after reading the Halo manual it clearly explains that this measurement is not a physical distance but an acoustic distance so I went with the 17’ that Auto-Cal gave and watched Master and Commander. Right or wrong the LFE effects were absolutely outstanding, the concussion of the cannon fire was perfectly spaced to give an illusion that I was right in the middle of the battle, every sound and vibration cue was spot on like I’ve never heard before, it was fantastic even without my bass shakers hooked up.

I have a theory that the reason everybody’s Auto-Cal gives such a long distance is that the processor is setting up a time delay relative to the other speakers, and that this obviously long measurement of 17’ (physically 7’) is a product of that Time Alignment, and in fact is correct acoustically speaking. Most of you have probably already come to the same logical conclusion, but with all the recent threads on many forums about the Sub distance always being so much longer then the physical measurements I thought it was a good time for a poll. I’ve tried both and much prefer the Auto-Cal distance.

So who has tried both (physical & Acoustical) distances entered into the setup page, and which do you prefer?

I have mentioned this in another thread, but I curious as to what others think.

[nicholtl]

I've tried using the distance it gave me (19 feet) and then setting the actual distance (13 feet). Personally, i don't think I could really tell the difference. Granted, I don't have the largest of rooms, maybe about 700 square feet, but they seemed to sound identical to me. So i figured i'd just leave it to the distance the autocal originally set by itself.

[Chris D]

Actually, I've been really happy with the autocalibration results so far. I still haven't fully completed my theater with tweaking, so I can't say for sure, but up to now it's been great to have something so fast and easy.

[nicholtl]

...so fast and easy.

Yep, nobody ever complained about anything being too fast and easy. 8O

[Omen]

Auto-cal for me.

[MarkStega]

Auto cal for me -- 18' by calibration, 7' physical; I started with manual entries (needed to buy an extension cable for the microphone as the C2 is in an equipment closet behind the screen of my theater) and had such an improvement overall after the auto cal I never even thought of going back!

[Chris D]

Just to specify, my auto-cal setting is 18', but actual is only 11' or so. BIG difference in the two values. I'm still leaving it on the auto-cal setting for now.

[Brian]

Auto-cal for me too. I tried putting in the actual distance and it was either not different or my head was telling me that 18' sounded better. So I left it at 18'.

[Rags]

Manual for all distances here. For the speakers the autocal was very close to the actual distances but the sub was way off. Your supposed to specify distance to set the delay - I thought its as simple as that - as my C2 gets the sub distance wildy wrong I prefer to set it manually.

I leave the C2 to autocalibrate the levels but I set the sub to run 3db hot. There is something about the LFE out of the C2 that I love. My ASW850 through the C2 and a BFD sounds superb - quite comfortably the best component of my home cinema system.

Also before calibrating leave the sytem runnng for an hour - I find that this produces different results from calibrating a system from cold.

[Chetk]

I find that the auto-calibration is great for everything BUT my sub. After I perform an auto-calibration, I have to turn the sub up 6 to 8 db. :E AND I turn the master bass up to 3 or 4. :E :E

It just always seems like, after I do an auto-calibration, the sub isn't loud enough for my taste. My friends notice it too by saying things like, "I like my movies to be a bit more bassy."

So, I guess I'm the only one. :huh:

[Rags]

You might have a big dip - have you tried plotting your frequency response ?

If you have, a BFD can make a big difference. I had a large peak which the BFD ironed out easily and as a result the bass sounds a lot more clearly defined, tighter, even and no boom whatsoever. Without meaning to change the topic of this thread below is a before (blue) and after (purple) graph of my ASW850.

[Chris D]

Good stuff, Rags. I too have a BFD for my dual SVS PC-Ultra subs, but haven't hooked it up and calibrated it yet.

For those using manual settings, I want to make sure you're at least aware of the owner's manual for the C1 and C2, where it specifically points out under the calibration section that auto-cal of the subwoofer very well may give a very different measurement than physical distance. It gives an interesting explanation there that it is due to the ACTUAL time delay received by your sub calibration signal, corrected for pressure altitude and temperature. The inference here is that the auto-cal would be more correct than the physical distance.

[Rags]

Two PC Ultras sound like damn fine bass. I have heard one in a smallish room and it truly is an impressive performer (better than the PB2+ imho unless you have a large room).

I had better read up on the the C2 users manual again but why doesnt the same apply to the other speakers ? Also in terms of distance setting for the other speakers, how accurate do people find the C2 to be to actual distance ?

[Rags]

Actually I just ran the distance autocalibrate once again and the results were -

========================Actual
Left Front------4.0m-------------4.0m
Centre---------5.0m-------------4.0m
Right Front-----4.7m-------------4.0m
Right Rear------3.8m-------------2.0m
Left Rear-------4.7m-------------2.0m
Subwoofer-----7.5m-------------4.0m

Excluding the sub even the speaker distances are pretty shocking (esp the rears!). I retried it with similar results. I recall it being a bit more accurate than that. I have left the sub at 7.5m but have reset the speakers to their actual distances as I felt the timing was out running a couple of test sequences from Black Hawk Down and Master and Commander. So who said this thing was accurate :evil: :

[Kingdaddy]

How are you setting up the Mic? I use a tripod in my listening position and place a few pillows and a heavy blanket around the tripod to adsorb like a body would. I also make sure the microphone is extended with the head as far away from the tripod structure and pointed up where my ears would be. I also put a small piece of padding under the mic so it won’t directly touch the tripod mount. I have measured many times and all of them are spot on except the subwoofer, and the subwoofer will, and should measure longer then the physical distance for proper time alignment.

Always do the level calibration first, I believe they are connected. Then make sure you have a good battery in the mic, and watch the cal procedure and see how close the 3 measurements are to each other, and how many times it has to try to get a good cal. It helps to lower the background noise as much as possible, shut off the A/C and any lighting and be very quite during the test; the tiniest noise will throw off or invalidate the cal. If you get a good cal then run it again and see if it comes up with the same numbers, if you get two in a row that are very similar you should be good to go.

[Rags]

Setting it up in a similar way - pointing directly upwards etc. Same readings again - room dead silent. At the end of the day it doesnt matter though as manual distance setting isnt difficult.

[Swfalcon]

Auto cal for me too...
I haven't felt any difference changing the distance to the "real" one...

[nicholtl]

I just experimented too. Autocal has it set to 15ft for me, when in actuality it's about 20ft. I know, that isn't too drastic a difference. Anyway, it sounds exactly the same to my ears, but nevertheless I'm going with what the manual says and leaving it to what autocal told me to do.

[SpOoNmAn]

Ive ran the auto cal 3 times in 6 weeks, and it gives me the same results every time, so atleast its consistent!

the actual sub distance is 8 feet but it gives me 15ft for the final setting. Ive gone back and forth, and like many of you, decided to keep the setting the Halo gave it :T

[nicholtl]

Yup! :T back at ya!

[Rags]

Excluding the sub id the auto cal working out the correct distances for all your othr speakers ? If so why the hell is mine so out ?

[nicholtl]

It should be accurate to within a foot.

[MarkStega]

Rags,

The most likely suspect is the room itself. When I played with the autocal before I had carpet, furniture, draperies, etc in my theater, the distances were way off and the sound was terrible. I presumed then & still believe that the simple issue was reflection of sound and the utter lack of absorbing surfaces. Clapping your hands produced a noticeable ringing. The front speakers measured all over the place and differed on each measurement.

When all the absorbtive stuff was installed, the calibaration was redone, and accurate to within a measured foot, except the sub (like I said above 18' measured by calibration, 7' actual); And now the sound is superb.