Messin with the subwoofer calibrations [Archive] - Audio & Video Forums

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3db
11-22-2005, 05:58 AM
I've calibrated my HT system using Sound & Visions test DVD and a Rat Shack SPL.. (Just an aside, Radio Shack in Canada is now known as "The Source" ) So my system is all calibrated up and I put in XXX and everything is rattling down thats not bolted down. Pretty cool I think to myslef. Last night, I brought home Harry Potter "Chamber of Secrets " speciall DVD set for $12.00 Cdn and found myself truning up the bass on the sub. I know not all DVDs are recorded the same, espcially with bass. Just wondering how many of you adjust their subs even after calibration to suit your tastes?

bfalls
11-22-2005, 06:48 AM
One thing you need to be aware of is the RS analog meter isn't flat. You can find the correction chart at http://www.users.bigpond.com/bcolliso/SPL-corrections.htm. Also, there's a bass calibration difference of 4db between DD and DTS.

That being said, I also adjust my bass/subs according to taste. My Legacy Focus mains with their 3 12" woofers/ch can get pretty agressive on movies with substantial bass. I have them bi-amped with a Yamaha M-65 A/AB 170W/ch amp in my 12.5'x25' room. I'm more into quality than quantity and although the Legacys can provide both, if the bass gets too loud it starts to rattle windows, pots and pans and nick-knacks which can be very annoying. It's not unusual to vary the bass 4-6db between different movies.

Pat
11-22-2005, 07:03 AM
Seems like I'm always messing with my sub and generally need to turn it up for movies. It's a lot of fun and at low volume being able to crank the bass really brings out the best in old classical music.

GMichael
11-22-2005, 07:09 AM
I set up my system several ways and put them all in the receiver's memory. When I want to watch movies I use #1, #2 for music, 3 for TV, 4 for football, 5, 6.

Bfalls, nice speakers. I mean, VERY NICE SPEAKERS!

Woochifer
11-22-2005, 04:04 PM
I've calibrated my HT system using Sound & Visions test DVD and a Rat Shack SPL.. (Just an aside, Radio Shack in Canada is now known as "The Source" ) So my system is all calibrated up and I put in XXX and everything is rattling down thats not bolted down. Pretty cool I think to myslef. Last night, I brought home Harry Potter "Chamber of Secrets " speciall DVD set for $12.00 Cdn and found myself truning up the bass on the sub. I know not all DVDs are recorded the same, espcially with bass. Just wondering how many of you adjust their subs even after calibration to suit your tastes?

Generally, you want to have the bass at least 4 db higher than the mains because our ears are less sensitive in the lower frequencies. Also, as others have pointed out, the Radio Shack SPL meter also requires a correction that increases as you go lower. With a wideband test tone, you should probably apply a correction of about 2-3 db.

Keep in mind that yes different movies are mixed at very different levels in the bass, but also the areas of emphasis can differ as well. That Harry Potter soundtrack I recall has some deep bass in it, and if it goes outside of your subwoofer's range, then you won't hear it. And some DVD soundtracks just plain overshoot the bass (best example of this is the LOTR:FOTR theatrical cut DVD, which pushed the levels beyond the distortion point).

As far as adjusting the bass to suit, I will do that every now and then. But, in general I have my subwoofer set at +6 db from the mains, which works well with most of my sources.


Also, there's a bass calibration difference of 4db between DD and DTS.

That sounds more like the dialog normalization offset, which is not specific to the bass/LFE calibration. The industry standard offset is -4 db for DD soundtracks (DTS does not use dialog normalization), which is why DD soundtracks almost always don't sound as loud as DTS soundtracks. Some DD soundtracks do not use dialog normalization at all. Best thing to do is use a SPL meter and measure the prevailing levels and adjust them accordingly if you're trying to do comparisons.

With the bass, there is a difference of 10 db between the LFE levels with DD and DTS in a lot of early home theater receivers/processors. This primarily occurred with units made four or more years ago. With those receivers/processors, you have to adjust the DTS LFE level (not the overall subwoofer output level) by +10 db to match the LFE output with DD. With anything made within the last four years, you don't have this problem.

bfalls
11-22-2005, 09:25 PM
I set up my system several ways and put them all in the receiver's memory. When I want to watch movies I use #1, #2 for music, 3 for TV, 4 for football, 5, 6.

Bfalls, nice speakers. I mean, VERY NICE SPEAKERS!


Thanks, I really enjoy them. I mean, I REALLY ENJOY THEM. I've heard many excellent high-end speakers over the years. I don't think you can beat the Legacys for bass reproduction, excellent extension, never distorted or boomy. The Focus are truly a class act.

My son is out of college and on his own, so we're taking over his bedroom and dedicating our current 12'x25' bedroom to home theater (my wife wants her living room back). We currently have a Klipsch HT in the bedroom with Kg4 mains, KV-3/KLF-C7 center, RS-3 front and rear surrounds, ACI Saturn and Klipsch SW8 subs with Yamaha RX-V2095 receiver and Marantz M-700 sub amp. I'm hoping to incorporate the Legacy HT into the room to accomodate my different listening moods. This is such a great hobby.

3db
11-23-2005, 11:07 AM
One thing you need to be aware of is the RS analog meter isn't flat. You can find the correction chart at http://www.users.bigpond.com/bcolliso/SPL-corrections.htm. Also, there's a bass calibration difference of 4db between DD and DTS.

That being said, I also adjust my bass/subs according to taste. My Legacy Focus mains with their 3 12" woofers/ch can get pretty agressive on movies with substantial bass. I have them bi-amped with a Yamaha M-65 A/AB 170W/ch amp in my 12.5'x25' room. I'm more into quality than quantity and although the Legacys can provide both, if the bass gets too loud it starts to rattle windows, pots and pans and nick-knacks which can be very annoying. It's not unusual to vary the bass 4-6db between different movies.

Quick question,,,the Sound and Vision /Avia test DVD tests the sub in several ways. One i sthe outright level check but I do not know which frequency is being used. The 2nd one is the frequency sweep from 200Hz down to 20Hz to make sure the crossover points between mains and sub are set so that there are flat spots or frequency humps.

GMichael
11-23-2005, 11:13 AM
Thanks, I really enjoy them. I mean, I REALLY ENJOY THEM. I've heard many excellent high-end speakers over the years. I don't think you can beat the Legacys for bass reproduction, excellent extension, never distorted or boomy. The Focus are truly a class act.

My son is out of college and on his own, so we're taking over his bedroom and dedicating our current 12'x25' bedroom to home theater (my wife wants her living room back). We currently have a Klipsch HT in the bedroom with Kg4 mains, KV-3/KLF-C7 center, RS-3 front and rear surrounds, ACI Saturn and Klipsch SW8 subs with Yamaha RX-V2095 receiver and Marantz M-700 sub amp. I'm hoping to incorporate the Legacy HT into the room to accomodate my different listening moods. This is such a great hobby.

HAHAHA Anytime. I have been looking at those for about a year now. Too bad that looking is all I can afford. Very impressive though.
Yes, this is a great hobby. Even my modest system sounds incredable. Much better than the sound at a theator.

Woochifer
11-23-2005, 07:14 PM
Quick question,,,the Sound and Vision /Avia test DVD tests the sub in several ways. One i sthe outright level check but I do not know which frequency is being used. The 2nd one is the frequency sweep from 200Hz down to 20Hz to make sure the crossover points between mains and sub are set so that there are flat spots or frequency humps.

That test tone on the S&V disc covers the entire lower frequency range. Not sure where it drops off, but just know that it is a different tone than the one used for the mains and surrounds. The mains and surrounds use a wideband test tone that has the lower frequencies filtered out, which makes the SPL readings a lot more accurate than other wideband test tones (such as the ones that a lot of receivers generate) because the room boundary gain and other acoustical effects in the lower frequencies can create erroneous readings.