Confusion about subs and calibration and SPL

[ChrisJam]

I was going to post this in the ongoing sub/SPL thread
(http://forums.audioholics.com/forums/showthread.php?t=50692), but decided to start a new thread, instead.

OK, I'm confused again.

Let me get one dumb thing I recently wrote out of the way: I said I'd try to see what freq my AVR subwoofer test tone was. Dumb! It's pink noise, not a single note.

I found my Rives test CD. It doesn't have test tone tracks for individual speakers. Plus, its single freq tones are louder than my AVR's by a lot.

OK, I could run my mains and see where they fall on the meter, using Rives's series for my RS meter. I could then run tones for the sub from the same disc. Then I could run my five speakers and do the sub again. But that doesn't seem right. (I could also buy a better HT set-up disc with better audio test tracks.)

I could unhook speakers so that only one would run at a time. But I use bare wire, and that'd be a PITA, frankly. Uh-uh.

Let's get back to the subwoofer freqs, SPL, and the Radio Shack meter.

OK, I understand that if I match my sub to my other speakers using the AVR's test tone and my RS meter, the sub would be 7.5 dB hot, assuming the test tone was at or near 20 Hz. From 50-80 Hz, the difference is 1.5 Hz. The difference increases fairly linearly from 50 Hz down to 20 Hz.

For the sake of arguement--this might be way off base--I'm going to assume that the Yammy AVR uses pink noise that averages to somewhere in the not-too-deep but not-too-high subwoofer freqs. After all, many people have subs that don't do much below 30 Hz. So let's say that my RS meter is off by a middle value of 2.5-3 dB. Let's use 3 dB for arguement's sake.

OK, I run my test tones, and set all my speakers to 80 dB, including my sub. The sub therefore runs 3 dB hot.

BUT--most people don't perceive low freqs as loudly as they do mid-range freqs of the same SPL. So that means that instead of being 3 dB hot, the sub is perceived as being...what...only 1-2 dB hot?

Since many audio experts say that they prefer a slightly hot sub--sure, it all comes down to personal preference, so it'll be different for all users--they set their sub 3-5 dB hot.

Assuming these people used a RS meter instead of a pro-quality one, would that be 3-5 dB hot over the sub matching the other speakers? That'd make it 6-8 dB hot. Then because we don't perceive low freqs to be as loud...

Agh--Im confused.

Here's where I have everything right now: my five speakers are set to 80 dB. My sub's set to 1-1.5 dB hotter, which means it's probably 3-4.5 dB hotter, give or take. Then that loudness is diminsihed by low freq perception, so I'm back to somewhere around 2-3 dB hotter.

It sounds good here, and I'll keep playing various music. I'll watch a DVD with good sub effects, too, though probably not tonight.

But I'd appreciate it if some of you experienced sub/calibration people could tell me if I'm on the right track with my thinking.

BTW, I'm not a bass freak. I like my lowest freqs to match other freqs. (I realize I probably have nodes in the room, but I'll deal with that later. My room is fairly well treated, though, and the sub almost has to live where it is.) When I listen to rock, I like a good bass kick, but not to an extreme. I like pipe organ music to have strong, but not overpowering, bass. I like good LFE slam with a DVD, but not to distraction.

Oh, and my sub is an av123 MFW-15, so it can reach deep. It has no problem doing 20 Hz in my room.

Thanks,
Chris

 

[croseiv]

Just set your sub even with your mains and be done with it. You're already there! Nothing to lose sleep over.

 

[ChrisJam]

Just set your sub even with your mains and be done with it. You're already there! Nothing to lose sleep over.

Thanks for the info. I guess my RS meter, my AVR's test tones, wanting the sub a little hot but not too hot, and our ears' perception of low-freq SPLs even out, huh? That's almost too easy.

Chris

 

[ChrisJam]

croseiv,

I just looked at the links in your sig. Are those two PB-13 Ultras? Wow!

May I ask? How do you have them set in relation to the SPL of the rest of your system?

Chris

P.S. When I bought a new sub this year, my final choice came down to the MFW-15 and the PB13-Ultra. I chose the MFW mostly because it would match the cherry satin veneer of the other av123 speakers I ordered at the same time.

 

[croseiv]

croseiv,

I just looked at the links in your sig. Are those two PB-13 Ultras? Wow!

May I ask? How do you have them set in relation to the SPL of the rest of your system?

Chris

P.S. When I bought a new sub this year, my final choice came down to the MFW-15 and the PB13-Ultra. I chose the MFW mostly because it would match the cherry satin veneer of the other av123 speakers I ordered at the same time.

Thanks! I have my Ultras set at 73 dB and my mains are at 75 dB (for HT). But for music I may push them up by as much as 5-6 dB depending on what I'm listening to.

 

[croseiv]

I should add that I calibrated with Avia II's advanced sub tones. The sub's warble tone is pretty deep in that set.

 

[ChrisJam]

I should add that I calibrated with Avia II's advanced sub tones. The sub's warble tone is pretty deep in that set.

OK, sorry, I have to ask: what do two Ultra-13s give you that one Ultra-13 turned higher wouldn't give? I'm asking because your room doesn't look too wide. I realize that it might be really deep and then open to other rooms, thus loosing subwoofer SPL. If the ceiling is high, I'd understand, too. It's all about cubic footage.

But the Ultra-13 is a monster. It outperforms my MFW-15 (though they come fairly close on CraigSub's list). I now have my AVR (in pre/pro mode) sending a middle-strength signal to the sub (neither plus nor minus). I have my MFW-15 at about 10:00 or maybe 10:30 on its gain/volume dial.

If this is good enough, what would I do with two MFW-15s, as some people buy? Stack them and set the gain to half of what my one is set at?

There's a caveat: We do not have room for a second big sub now. But given how powerful the MFW-15 is, I can't imagine needing a second for even a fairly large room.

Please educate me.

Chris

 

[croseiv]

With dual Ultras I get much better overall performance! With one Ultra I experienced a fair amount of port noise at high volumes, and I could tell the sub's sound was beginning to reach its limits. With duals, there's no port noise on the same demanding tracks at the same volume. Also, dual subs give an additional 6 dB of headroom (volume capability really). Meaning I could essentially turn my volume knob six dB higher than with one. The net effect is a much more enjoyable LFE experience because each sub has to work less to achieve the same SPL as one. THe drivers are running well within their design limits and sound better, and the dynamics are tremendously improved. With one Ultra it seemed as I could nearly shake the cabinets off the walls. With dual Ultras I can. Duals shake the whole house. It's about headroom. When Iron Man goes supersonic, you really feel the sonic boom. There's an extra deminsion to the bass that's not there with one.

 

[ChrisJam]

With dual Ultras I get much better overall performance! With one Ultra I experienced a fair amount of port noise at high volumes, and I could tell the sub's sound was beginning to reach its limits. With duals, there's no port noise on the same demanding tracks at the same volume. Also, dual subs give an additional 6 dB of headroom (volume capability really). Meaning I could essentially turn my volume knob six dB higher than with one. The net effect is a much more enjoyable LFE experience because each sub has to work less to achieve the same SPL as one. THe drivers are running well within their design limits and sound better, and the dynamics are tremendously improved. With one Ultra it seemed as I could nearly shake the cabinets off the walls. With dual Ultras I can. Duals shake the whole house. It's about headroom. When Iron Man goes supersonic, you really feel the sonic boom. There's an extra deminsion to the bass that's not there with one.

I can understand the extra headroom comment. After all, I recently boght a good external 200-watt, 7-ch amp to run my system, freeing my AVR to only do pre/pro duty.

But even when I run loud music or a loud movie*, my sub runs nowhere near its capacity. At least I think it doesn't.

* Tonight we watched the DVD "The Core." Not a great movie in spite of having some fine actors, but it had a lot of good LFE sounds. You know from my last post where my system is set. (One thing I didn't mention, though, is that the gain know of the sub is set to 10/10:30, with lots of room to grow, if needed.)

Yours is the first comment I've read about PBUltra-13 port noise, and I've read many, many forum threads on it, as well as many, many reviews, and miscellaneous web sites. (Some people complain about chuffing from the MFW-15, but mine's been fine {knock on wood}.)

Maybe your room is bigger than mine. That might explain it.

Getting back to my sub and SPL, before I started calibrating it, when I just did Yammy's auto set-up and then tweaked it by ear, some household things rattled. I heard it most, though, when I was outside and heard the front storm windows vibrating in their slots. I haven't checked outside since running my meter.

I was happy with tonight's LFE in "Core." As I said, the Ultra was my second choice. Though it's an overall better sub, I can't see it obviously outdoing the MFW-15 in my room (I stress "in my room"). This room, BTW, opens up to a dining room on one side, plus a foyer a little bit to the side and behind, and then onto a kitchen through two doors. Past the foyer is a stairway leading upstairs. Still, it's not a large space, and the ceiling at this level is just 7 1/2-feet high.

Considering that my sub's gain knob is set no higher than 10:30, I doubt I'd benefit from a second sub. As far as I know, I have enough headroom for now. LOL--that said, I've read about many people who have bought 2, 4, 6, or even 8 MFW-15s for their HT, and some of the rooms that the subs are in aren't that big.

I'll keep your sub/headroom comment in mind, though, if we move and set up the HT in a bigger room.

If you think Im missing something obvious, please feel free to tell me.

OK, time for bed.

Thanks again,
Chris

 

[ChrisJam]

It's about headroom. When Iron Man goes supersonic, you really feel the sonic boom. There's an extra deminsion to the bass that's not there with one.

I forgot to mention that I haven't seen this movie. My gf doesn't want to see it, even though she liked Robert Downey. She has an out of town trip next month, so I'll probably rent it then and watch it. I might invite a friend to come over to share.

Chris

 

[croseiv]

I can understand the extra headroom comment. After all, I recently boght a good external 200-watt, 7-ch amp to run my system, freeing my AVR to only do pre/pro duty.

But even when I run loud music or a loud movie*, my sub runs nowhere near its capacity. At least I think it doesn't.

* Tonight we watched the DVD "The Core." Not a great movie in spite of having some fine actors, but it had a lot of good LFE sounds. You know from my last post where my system is set. (One thing I didn't mention, though, is that the gain know of the sub is set to 10/10:30, with lots of room to grow, if needed.)

Yours is the first comment I've read about PBUltra-13 port noise, and I've read many, many forum threads on it, as well as many, many reviews, and miscellaneous web sites. (Some people complain about chuffing from the MFW-15, but mine's been fine {knock on wood}.)

Maybe your room is bigger than mine. That might explain it.

Getting back to my sub and SPL, before I started calibrating it, when I just did Yammy's auto set-up and then tweaked it by ear, some household things rattled. I heard it most, though, when I was outside and heard the front storm windows vibrating in their slots. I haven't checked outside since running my meter.

I was happy with tonight's LFE in "Core." As I said, the Ultra was my second choice. Though it's an overall better sub, I can't see it obviously outdoing the MFW-15 in my room (I stress "in my room"). This room, BTW, opens up to a dining room on one side, plus a foyer a little bit to the side and behind, and then onto a kitchen through two doors. Past the foyer is a stairway leading upstairs. Still, it's not a large space, and the ceiling at this level is just 7 1/2-feet high.

Considering that my sub's gain knob is set no higher than 10:30, I doubt I'd benefit from a second sub. As far as I know, I have enough headroom for now. LOL--that said, I've read about many people who have bought 2, 4, 6, or even 8 MFW-15s for their HT, and some of the rooms that the subs are in aren't that big.

I'll keep your sub/headroom comment in mind, though, if we move and set up the HT in a bigger room.

If you think Im missing something obvious, please feel free to tell me.

OK, time for bed.

Thanks again,
Chris

I'm certainly not advising you to run out and get duals. As I said it was nearly a year before I got the second Ultra (although I wanted two at the time I got a single). I was very surprised at the increased performance of going to duals though. It's not eveident in my sig. photo, but my listening area is roughly 5500 cu. ft. which is right on the edge of comfort for a single Ultra. I could reach the limits with a single pretty easily, duals give me the slam I want effortlessly now.

I originally had a Polk Audio PSW-650 sub, and moved to an Ultra. That was a huge upgrade. One Ultra is the equivalent of roughly 3 650s output wise, but the 650 had no where near the extension of an Ultra. Going to duals was just as huge. Don't let the 13" driver fool you either. It's a beast!

 

[ChrisJam]

I'm certainly not advising you to run out and get duals. As I said it was nearly a year before I got the second Ultra (although I wanted two at the time I got a single). I was very surprised at the increased performance of going to duals though. It's not eveident in my sig. photo, but my listening area is roughly 5500 cu. ft. which is right on the edge of comfort for a single Ultra. I could reach the limits with a single pretty easily, duals give me the slam I want effortlessly now.

I originally had a Polk Audio PSW-650 sub, and moved to an Ultra. That was a huge upgrade. One Ultra is the equivalent of roughly 3 650s output wise, but the 650 had no where near the extension of an Ultra. Going to duals was just as huge. Don't let the 13" driver fool you either. It's a beast!

No, I can't get a second sub now; I have no room for it. That'll have to wait until we move in a few years.

There's no question your Ultra is super with its 13-incher. In fact, according to CraigSub's list, it outperforms my 15-inch MFW-15. I came very close to getting the Ultra, but in the end I wanted to have all my speakers match. That said, if I ever run into trouble with mine--it's been trouble-free so far, knock on wood--I'd make the switch to the Ultra.

Chris

 

[no. 5]

I was going to post this in the ongoing sub/SPL thread
(http://forums.audioholics.com/forums/showthread.php?t=50692), but decided to start a new thread, instead.

OK, I'm confused again.

Let me get one dumb thing I recently wrote out of the way: I said I'd try to see what freq my AVR subwoofer test tone was. Dumb! It's pink noise, not a single note.

I found my Rives test CD. It doesn't have test tone tracks for individual speakers. Plus, its single freq tones are louder than my AVR's by a lot.

OK, I could run my mains and see where they fall on the meter, using Rives's series for my RS meter. I could then run tones for the sub from the same disc. Then I could run my five speakers and do the sub again. But that doesn't seem right. (I could also buy a better HT set-up disc with better audio test tracks.)

I could unhook speakers so that only one would run at a time. But I use bare wire, and that'd be a PITA, frankly. Uh-uh.

Let's get back to the subwoofer freqs, SPL, and the Radio Shack meter.

OK, I understand that if I match my sub to my other speakers using the AVR's test tone and my RS meter, the sub would be 7.5 dB hot, assuming the test tone was at or near 20 Hz. From 50-80 Hz, the difference is 1.5 Hz. The difference increases fairly linearly from 50 Hz down to 20 Hz.

For the sake of arguement--this might be way off base--I'm going to assume that the Yammy AVR uses pink noise that averages to somewhere in the not-too-deep but not-too-high subwoofer freqs. After all, many people have subs that don't do much below 30 Hz. So let's say that my RS meter is off by a middle value of 2.5-3 dB. Let's use 3 dB for arguement's sake.

OK, I run my test tones, and set all my speakers to 80 dB, including my sub. The sub therefore runs 3 dB hot.

BUT--most people don't perceive low freqs as loudly as they do mid-range freqs of the same SPL. So that means that instead of being 3 dB hot, the sub is perceived as being...what...only 1-2 dB hot?

Since many audio experts say that they prefer a slightly hot sub--sure, it all comes down to personal preference, so it'll be different for all users--they set their sub 3-5 dB hot.

Assuming these people used a RS meter instead of a pro-quality one, would that be 3-5 dB hot over the sub matching the other speakers? That'd make it 6-8 dB hot. Then because we don't perceive low freqs to be as loud...

Agh--Im confused.

Here's where I have everything right now: my five speakers are set to 80 dB. My sub's set to 1-1.5 dB hotter, which means it's probably 3-4.5 dB hotter, give or take. Then that loudness is diminsihed by low freq perception, so I'm back to somewhere around 2-3 dB hotter.

It sounds good here, and I'll keep playing various music. I'll watch a DVD with good sub effects, too, though probably not tonight.

But I'd appreciate it if some of you experienced sub/calibration people could tell me if I'm on the right track with my thinking.

BTW, I'm not a bass freak. I like my lowest freqs to match other freqs. (I realize I probably have nodes in the room, but I'll deal with that later. My room is fairly well treated, though, and the sub almost has to live where it is.) When I listen to rock, I like a good bass kick, but not to an extreme. I like pipe organ music to have strong, but not overpowering, bass. I like good LFE slam with a DVD, but not to distraction.

Oh, and my sub is an av123 MFW-15, so it can reach deep. It has no problem doing 20 Hz in my room.

Thanks,
Chris

For what you are wanting to do (know?), an SPL meter is WAY to low resolution to let you know what you need to know; all it's telling you is the 'average' volume of all the sounds that are present. Your ears are much smarter than that, what you need is an RTA, or some manner of spectrum analyzer, that will give you a better picture of the relative volume of the sub and other speakers.

Visual Analyzer is freeware that will do what you need, and you can use the RS meter as a microphone.