STF-2 Claibration

[Ajax]

My STF-2 just arrived this afternoon. Hooked it up, no calibration or any other adjustment. One word. Smooooooooooth! No more "boom boom."

I'm not real familiar with how to calibrate the sub. Can anyone recomend somwhere to find instructions on how to do the calibration?

Will the audio test tracks on Joe Kane's Digital Video Essentials (which I have) do the job? Or, should I order the Stereophile Test CD 1 recommended in the STF-2 manual?

I've got both the digital Radio Shack SPL meter, and an older Radio Shack analog SPL meter (not the new one).

[outflying]

I'm really excited!!! Just got STF-3 and VT-12's. Wired everything today. Went to rat shack and bought SPL meter. Downloaded all of the test tones. I'm ready to go... except one thing:

I HAVE NO CLUE WHAT I'M DOING!!!

I've never done any of this before. I've done a tone of readind. I had the same problem with starwars popping like that that other guy had... so I turned down.

Is there some place that tells you how to do this step by step? I have the compensation numbers printed out that someone posted.

So you play one of the 1/3 octive tones and look for what???

Please help.

Thanks

:confused:

[Ajax]

Well you're in the same boat I'm in.

Somewhere I've read instructions on how to do this calibration but I can't remember where. (Stop laughing! Wait 'til you're old!)

I think you're supposed to set the SPL meter to the 70db scale, and go from there. But, go where?

Also I know the meter itself has a roll off at lower frequencies that must be taken into consideration when calibrating the subwoofer, but I don't know how much of a roll off or where it starts.

I'm a little stunned that in a whole week, your response is the only one. And, could you help? Nooooooooooo. ;) I've even done Google searches, and come up empty. Amazing!

I'm sure there are members on this forum that could steer us to some instructions on how to do this. Keep your fingers crossed. Maybe some kind poster will have pity on us, and lend a hand.

[Dudley]

You look for two things with the tones.

Deep Bass - see what volume you can get with the lowest tones.

Even response - the trick is to have all of the tones produce the same volume. You especially want to make sure that the sub is not set way to hot, so run tones that start at a frequency where the sattelites will do the work, and then move down untill all the sound is coming from the sub. If the sub volume is set correctly, then there will be no difference in the volume. Some do like to runthe sub a little hot (3 Db or so) to make up for the fact that at low volumes the human ear does hear deep bass as well.

You may have to fiddle with sub position, crossovers, and volume.

BTW I would be very interested in the actuall corrected decibel readings anyone gets for the actual tones, and would be curious about max Db as well.

[outflying]

I have the corrections from a different thread:

As far as setting it up by ear, its just always going to end up way too hot. We humans have funny judgement when it comes to balancing up bass with our ears. Remember when using the RS meter with bass you neeed to do the corrections because its not accurate.

10Hz add 20dB
12Hz add 16.5dB
16Hz add 11.5dB
20Hz add 7.5dB
25Hz add 5dB
31.5Hz add 3dB
40Hz add 2.5dB
50Hz add 1.5dB
63Hz add 1.5dB
80Hz add 1.5dB
100Hz add 2dB
125Hz add .5dB

I've done a bunch of internet searching. If I find more, I'll post.

[outflying]

So I guess what the meter is showing is nothing but DB's. I thought it was measuring HZ's also. O.k. I'm making progress. Don't laugh at the clueless wonder.

:p



What volume level would you recommend? 25% of max? 30? More?

Thanks

[Ajax]

Thanks so much guys. I do appreciate the help.

Outflying.

I'm not sure where to add the extra db. If, with, say, a 40 Hz tone, I wanted to set the volume at 75d db, would I adjust the volume until the meter read 72.5 db, or 77.5 db?

Thanks again.

[outflying]

You are brave asking me a question. LOL!

I think the way it works is that you add it to what the meter says: the meter is light.

So for your example ...

If your meter is reading 72.5 at 40hz you neet to add 2.5db. You're actually getting 75 db in that situation???

I'm brand new to all of this so this might not be correct. But its how I interpret the chart. Could anyone else confirm?

If you're at a 100hz freq and the meter says 80 db, you need to add 2 db to what the meter says. Therefore, your actual reading is 82 db.

[Ajax]

Ah yes! The blind leading the blind! :D

[outflying]

So to get the same dbs at all levels are you adjusting the level on your receiver or the gain on the back of the sub? Thanks.

[Dudley]

That is correct. The correction numbers are added to the reading you have, and the result is the actual number.

[Ajax]

Thanks Dudley! So the meter reading is on the light side. With a 40 Hz tone, when the meter says 72.5 db, you're actually getting 75 db. Whew! I hope I can retain that now.

Originally posted by outflying
So to get the same dbs at all levels are you adjusting the level on your receiver or the gain on the back of the sub? Thanks.

YES! ;)

From what I've gleaned so far, you should probably start with the setting on the receiver at 0db, and adjust the volume at the sub. If you find you're pushing the knob too high on the sub, then boost a little on the receiver. I'm ready and willing to be corrected by someone more knowledgeable.

[outflying]

Here is a good read

Article on Speaker calibration (http://www.htadvice.com/on_setup/speakers_calibration.html)

Speaker Calibration
Calibrating your speakers is one of the best things you can do to optimize your sound. What happens when you calibrate your speakers? You listen to test tones to measure the sound level of each speaker with an SPL meter. You then calibrate each speaker, including the sub, to produce the same level of sound. This creates very full and balanced surround sound. No one speaker dominates over the others, allowing all your speakers to work as a whole, creating an awe-inspiring sound system.

What You Need
To calibrate your system you'll need 2 handy little items. A RadioShack SPL meter, and a home theater calibration DVD. The SPL meter is the device used to measure sound. This allows you to compare the sound level of your speakers and calibrate their levels to match. The analog version is the best one to go with, as it measures more minute increments and runs about only $35. "Video Essentials" and "Avia: Guide to Home Theater" are home theater calibration DVDs that usually run about $40. You'll use the DVD to play a series of test tones which you will use to measure the sound level of your speakers. With these DVDs you'll also get in-depth tutorials on audio and video calibration.

You can use test tones produced by your receiver or processor, but they are not as accurate since the test tones aren't coming from the component you're going to be playing audio from (the DVD player). Using your receiver's test tones for calibration doesn't account for the affects the DVD player and the connecting cables have on the audio signal.

The calibration DVDs offer tutorials on why you should calibrate, and the purpose behind it all. You won't get a full tutorial of speaker calibration on this web site simply because these DVDs are the perfect resource for any home theater enthusiast.

Hints and Tips
Before calibrating your speakers you should set your bass and treble controls to zero. You don't want these controls maxed so your receiver/amp has some breathing room during loud audio segments. When listening at high sound levels you run a good risk of pushing your amps beyond their limit causing amplifier distortion or "clipping". All distortion is bad, but clipping is one of the worst kind. The amps signal is uncontrolled when it's clipping which can lead to speaker damage.

The best rule of thumb is to never set your tonal controls above half. Which usually means having the knob marker point at 3 o'clock. The best bet is setting tone controls to zero. At first your system may sound dull, but after you get used to this setting you'll realize the sound is actually smoother and more accurate than the bright and grating sound most people listen too. After a short while you wonder why you ever liked the old grating sound settings.

During the test tone sequence of the DVDs you'll need to keep your DVD remote handy so you can flip back to the beginning and retest the audio signals to get your speakers balanced. It should only take 2-3 three times to go through the speaker test tones to get all of your speakers balanced and working together.

How Often
If your speakers are new, they are going to go through a break-in period wherein the drivers loosen as you play them more often. Once your speakers break-in, the sound they emit will be very different from the sound you heard right out of the box. Some speakers take only a week of good play to break-in while others can take about 2 months to fully break-in. It is for that reason, within the first couple months of owning your new speakers, you'll need to calibrate them multiple times. Whether you decide to check every 2 weeks or every month is up to you, but you should recheck the sound levels within 3-months. After that, you shouldn't need to re-calibrate your speakers for another 6 months to a year or after any power outages.

After your subwoofer fully breaks-in you may find that the bass response has changed so much that it no longer sounds the way it did before. You may need to move the sub to a new location after it breaks-in to get the bass response the way you want it. (See placement for more info)

Break The Rules (It's Your System)
After getting your speakers properly calibrated you should notice a huge difference in how all your speakers blend together to produce a nice envelope of sound. However, you may find some aspects of the sound not to your liking. It's usually the surrounds and subwoofer levels in debate.

Try living with the surrounds properly calibrated before changing them. Most people prefer thier surrounds louder since they want to emphasize the fact they actually have surround sound, but after a while this desire fades and the enjoyment of the system as a whole brings far greater satisfaction with more accurate sound. If you still desire to turn up the surrounds after living with them don't hesitate to do so. In the end it's your system, and it should play the way you want to hear it.

After calibration you may find that that the sub has been calibrated too low for your taste. Raise the sub to a level that you like if you want more bass. It's hard to calibrate bass blindly. You run the risk of turning it up too much, producing bass that doesn't blend well with the other speakers and draws attention to itself.

If your listening to music and you find yourself glancing at the sub when it kicks in, you most likely have the sub up to high. The only way to calibrate your sub correctly is to start from the calibration point, and slightly turn it up followed by a quick test. It's shouldn't take to long to get it right, and you'll eventually find the level that's right for you. Again it's personal preference how you want your sub to sound. Speaker calibration gets your speakers to work together in perfect unison, and that's always a good place to start before tweaking the system to your tastes.

Special Cases
Some systems do not allow for the independent calibration of the main speakers and the surrounds and instead rely on balance controls. You will need to fiddle with the balance to get the main speakers to the same level before moving on to the other speakers. Surround speakers that can can't be independently calibrated may need to be physically moved to the right spot to create the perfect sound field.

[Ajax]

:D I do not pretend to understand any of this, but it is a start.
http://www.abluesky.com/p_s_gb/p5s10.html

Theory

The purpose of calibration is to adjust the overall electro-acoustic system gain so that 0dBVU of electrical signal level equals a certain acoustic level at the listening position. Since most recording media is now digital, the reference electrical signal level is usually –20dBFS with 20dB of headroom. The reference SPL level however can vary based on the delivery media and speaker type.

Please note, that the bandwidth limited signals that have been provided, limit many of the room interaction affects often associated with measuring SPL and broadband pink noise.

*Also note that the LFE channel gain in 5.1 formats varies from 0 to +10 dB depending on the encoding format used. Since the LFE channel is not calibrated as a separate entity, the LFE gain will not affect system calibration basis on these test tones.

The common calibration levels are listed below

Left, Center, Right, Left Surround, Right Surround, SUB*
Movie Theatrical release 85dB 85dB 85dB 82dB 82dB 85dB
Movie DVD release 85dB 85dB 85dB 85dB 85dB 85dB
Broadcast / 85dBC or 78dB 78dB 78dB 78dB 78dB 78dB
Music (Stereo) 85dB 85dB 85dB
Music (5.1) 85dB 85dB 85dB 85dB 85dB 85dB


All test signals are recorded at –20dBFS including the 1 kHz sine wave tone. The sine wave tone is used to set the electrical output level throughout the signal path, right up to the point you get to the speakers. While the various pink noise signals are used for acoustic measurements and calibration.

The following procedure assumes you are calibrating the system to 85dBC SPL. If you are calibrating to TV, etc. substitute the appropriate level from the above chart.

1. TURN OFF THE MONITORING SYSTEM (until step 4)

2. Remove all eq and dynamics from the signal path and set all controls to zero / unity gain.

Play the 1kHz Sine Wave, hard assign it to the left channel only, and adjust the output fader so the output meter reads -20dBFS. If you are using an analog console, set the output level to 0 VU. Then hard pan the signal to the right channel output and repeat for the right channel. For a 5.1 system assign the channel to each output and repeat the adjustment procedure. Once calibrated do not move the output faders.

3. Mute everything and make sure the 1kHz tone is OFF.

4. Now that the system has been electrically calibrated turn ON the SUB and SATs.

5. Assign the 500-2.5kHz pink noise signal to the left channel only. Make sure there is nothing coming from the right channel (or any other channels). Because this signal is bandwidth limited, you don't have to worry about turning the sub off. There are two methods of setting the levels.

a. If you have a master monitor level control, you can set the sat gain control at reference and then adjust the monitor gain control for 85 dBC. Then mark the monitor level as your reference position.

b. The other method is to set master monitor level to the position you want as a reference level and then use the volume controls to set 85 dBC. If you use this method you should mark the knob position with a grease pencil so you can always go back to reference level if the knob gets moved.

For either method:
SPL should be measured at the sweet spot, with the SPL meter at arms length, with the microphone at seated ear height, angled at approximately 45 degrees, and pointed at the center point between the left and right speakers.
Once the left channel is set to 85dBC, repeat this step for the right channel (and C, LS & RS in a 5.1 system).

6. Feed 40-80Hz pink noise signal to the left channel only. Adjust the subwoofer level control until the subwoofer reads 85dBC (slow) at the mix position. The meter will bounce around a little, so you will need to do a mental average (I tend to filter out the peaks in my mind, so I don't set the sub too hot). The right channel should measure about the same and no additional adjustments need to be made.

7. You can play the full-bandwidth pink noise, assigning it to the left and then the right channel (not at the same time). You should measure about 85dBc. It may be a little higher, because below 30Hz the room may have a little extra gain.
No adjustments should be made with Full Bandwidth pink noise, unless you have an RTA (real time analyzer).

8. You are finished and the calibration process has been completed – enjoy!

[outflying]

Thanks to all. With all of this new knowledge I'll try again today.

:)

[Submariner]

Originally posted by Ajax
Will the audio test tracks on Joe Kane's Digital Video Essentials (which I have) do the job? Don't use the lastest Digital Video Essentials to calibrate the subwoofer. The subwoofer test tone has been recorded too high, which means your sub will be a lot quieter. I have heard the tone is +2db to +13db too high, which would mean your sub would go the other way, -2db to -13db lower than it should be calibrated. Use the old Video Essentials, Avia, Ultimate Platinum or any other verified test tone.
Check this link out:
http://www.htcentral.net/community/viewtopic.php?t=1765

[fanuminski]

Does anyone know if the corrections
listed for the Radio Shack analog
SLM appyl to the digital version that
is currently sold?
Thanks!:)

[tdekany]

Originally posted by fanuminski
Does anyone know if the corrections
listed for the Radio Shack analog
SLM appyl to the digital version that
is currently sold?
Thanks!:)

The analog is back at Radio Shack

[fanuminski]

Yes, but I bought a digital several
months ago!:(
Do I need to use different adjustments?
thanks

[Gregisme]

at least in my local Radio Shacks, none of them have the new analog version yet, nor do they have any idea when it's supposed to show up.

[BASH]

Did you guys get the HSU disc with your subs. If so the tracks you will be interested in using are 10-21. When I calibrated my system I started by turning off the sub and set the volume on my amp to output around 75dB. Then I ran the disc to get an idea of what my mains were capable off, by the way keep pencil and paper handy to keep track of your readings, what volume output is at particular freq. Then I set the sub volume at about 9:30 and the cx at around the freq. where my mains started to rolloff. I then took numerous readings trying to get all of the different track volumes close, only adjusting the VARIABLE FREQ. knob.
This gave me a freq. response from 25hz. to 200hz. within 7dB.
Might not be perfect but it sure sounds good.
P.S. The freq. you should really concentrate on are 40hz thru 80hz. Good luck

[IJR]

OK. After reading through this thread and doing some extra research. I did my first "test calibration" last night on my existing equipment (Athena Micra 6 system with a Yamaha RX-V1400 receiver) while I still await the arrival of my STF-3.

All I had was the Radio Shack digital sound level meter and the Avia Guide to Home Theater DVD.

Here are the steps I took:

1. Set all volume levels for all speakers on the receiver to 0db. Set the volume knob on my subwoofer to the middle (as per the Athena owners manual).
2. Turned the knob on the Radio Shack meter to 80. Weighting C. Response Slow.
3. Turned the Master Volume on the receiver to 0db (this is pretty loud).
4. I then started playing the test tones on the Avia DVD one speaker at a time and adjusted the levels until they all equalled 85db.
5. Played the 5.1 surround tone that cycles through all the speakers continuously to make sure the level stayed at 85db throughout.

This was the extent of my tweaking as the Athena subwoofer only has a volume knob and that's it. I left the crossover point of my receiver at 80Hz, and the test tones that sweep from 200Hz to 20Hz seemed to produce no major drop-offs in volume.

Already, I noticed a big difference in terms of the cohesiveness of the sound as I tested some tried and true scenes from the DVDs I had (Phantom Menace pod racing scene, Minority Report factory shoot-out, and the Eric Clapton performance on the DTS Demo disc).

The Athena subwoofer went as low as around 36Hz before it dropped off big time and was totally inaudible around 30Hz. Although it's not bad, I am really hoping my STF-3 will give me that "major punch" that I am looking for. The rest of the Athena Micra 6 satellites aren't that bad considering the price ($550 for entire set with sub). I used to have B&W 601s and an LCR60 and those of course were noticeably better sounding.

I will re-calibrate my system when I receive the STF-3, so let me know if I am missing anything else from what I just did last night. It will probably be more involved with the STF-3 as it does have a few more bells/whistles than the Athena sub.

By the way, the Yamaha has an auto-setup system that sets all these levels by plugging in a small mic, putting it in your listening area, and it cycles through all its internal test tones. The levels that it set each individual speaker were much higher than my manual calibration last night. It also set the crossover to 200Hz rather than 80Hz. I guess it wants the sub to do more of the work and leave the satellites out of the low range. Should I stick with 200Hz or 80Hz or somewhere in between?

[Dudley]

The lower the crossover the harder it is to localize the bass. Of course you need speakers that can get down to that crossover or you will be missing info (In small bookshelf applications). A rule of thumb is 5 1/4" woofers should go to around 80 Hz or so. The Micras are pretty small (3.5" woofers -3db near 100 hz - if I remember right), so you might want to try 100 Hz.

Also if your sub is on the front wall with your mains, it will be harder to localise, even at higher crossovers.