ntrain42
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Post by ntrain42 on Mar 29, 2010 13:13:09 GMT -5
Yes, I am aware of the smoothing factor, but when using a pink noise frequency sweep(which does do 1hz increments from 10hz-300hz for 5 second intervals each)test track, the spl meter(which is accurate within +/- .25db) will still pick up any dips or peaks. Again this is where placement of the sub grouping is key. It's not the signal type but the smoothing function that hides peaks and dips. You simply can't see them with one-third octave resolution. And a single subwoofer or grouping multiple subwoofers at one location will make modal problems even worse. Would love to see the real low frequency response of your room. Have you ever used Room EQ Wizard or HOLMImpulse for measurements (both are free)? I've NEVER seen a room without modal problems. Best, Markus When in spl mode there is no smoothing function enabled(and the display's spectral function is bypassed and replaced with a numeric display), thats the whole point. With a sweep test track and spl mode enabled, it gives me exact output measures at any specific frequency played from a specific source and test track. I use this to finalize and fine tune end results. |
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Post by markus on Mar 29, 2010 15:03:45 GMT -5
Didn't know that your RTA can measure sound pressure levels. So you really go through 300 single 5 second long sine tones for every listening position and write down each value? Optimizing a setup with that method must take you weeks. With a computer you could do it in realtime.
Best, Markus
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ntrain42
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Post by ntrain42 on Mar 29, 2010 15:34:19 GMT -5
Didn't know that your RTA can measure sound pressure levels. So you really go through 300 single 5 second long sine tones for every listening position and write down each value? Optimizing a setup with that method must take you weeks. With a computer you could do it in realtime. Best, Markus Yep, mine will go up to 180db. I only set the mic up in 1 or 2 listening positions, and I only use the sweep below 120hz, only takes an hour roughly to fine tune the bass if even needed. |
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Post by markus on Mar 29, 2010 21:44:48 GMT -5
I only use the sweep below 120hz, only takes an hour roughly to fine tune the bass if even needed. Now I'm confused. You use a (one) sine sweep or single 5 second sine bursts? |
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ntrain42
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Post by ntrain42 on Mar 29, 2010 21:56:02 GMT -5
I only use the sweep below 120hz, only takes an hour roughly to fine tune the bass if even needed. Now I'm confused. You use a (one) sine sweep or single 5 second sine bursts? 5 second bursts per frequency point from 10-300hz. |
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Post by markus on Mar 30, 2010 9:44:50 GMT -5
Sounds like a very, very arduous process. White noise and a realtime FFT gives you something like this within seconds:  (Optimized)  (Unoptimized) Every change can be monitored in realtime. Best, Markus |
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ratmice
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Post by ratmice on Mar 30, 2010 10:34:58 GMT -5
Markus-
are those output graphs from REW (Mac)? or something else?
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ntrain42
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Post by ntrain42 on Mar 30, 2010 11:28:17 GMT -5
The way Ive been doing it, has been done for 15 plus years, well before REW or laptops were really accesable......to me its easy and 2nd nature, and the results are spot on. And everything is monitored on my RTA in real time as well.
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Post by markus on Mar 30, 2010 14:48:24 GMT -5
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Post by markus on Mar 30, 2010 15:03:06 GMT -5
The way Ive been doing it, has been done for 15 plus years, well before REW or laptops were really accesable......to me its easy and 2nd nature, and the results are spot on. And everything is monitored on my RTA in real time as well. I know that optimizations were done with one-third octave realtime analyzers in the past. That's exactly why EQs have such a bad reputation. You simply can't see the truth with a one-third octave realtime analyzer. EQ settings based on measurements with such a device will most certainly be off. Even if it's "easy and 2nd nature" to you you will have to find the right sinus burst, play it, read the meter, write it down and draw a curve. Then you have to repeat it with every single change in settings. I don't know how experience can speed up that process considerably. |
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ntrain42
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Post by ntrain42 on Mar 30, 2010 15:26:53 GMT -5
1/3 octave analysers have enough resolution to localize any major dips or peaks. Frequency sweeps and spl readings help to fine tune and verify the results.
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Post by Deleted on Mar 30, 2010 15:39:05 GMT -5
And if I am correct a 6Db gain with two subs stacked or side by side. Seperated about a 3Db gain. That is correct, ntrain will disagree but he is wrong. 2 subs placed in different locations around the room will add about 3 db's more. Placed together they will net you about a 6db increase. |
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ntrain42
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Post by ntrain42 on Mar 30, 2010 15:56:19 GMT -5
And if I am correct a 6Db gain with two subs stacked or side by side. Seperated about a 3Db gain. That is correct, ntrain will disagree but he is wrong. 2 subs placed in different locations around the room will add about 3 db's more. Placed together they will net you about a 6db increase. I am wrong? So is a calibrated RTA wrong as well when I add a second sub(with identical gain set)in a different location in proper phase with the first to show roughly 6db gain?  So what would you believe? A calibrated pair of subs and an RTA/SPL meter accurate within .25db or someone who doesnt have the extensive experience with multiple sub setups. |
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Post by Deleted on Mar 30, 2010 16:09:50 GMT -5
Yes you are wrong. It's ok, it happens  |
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Post by Deleted on Mar 30, 2010 16:26:49 GMT -5
Can you see the problem ntrain? you keep stating this as what you are going to get every time you add a second sub. It's just not the case. You have no idea what someones room is setup like and you just keep stating it as an absoult fact when it's not.
Lets say your getting rid of some nasty nulls in your room, let's say the room is 14 x 20 x 8 foot celings. you put 1 sub at the front soundstage and 1 sub in the rear of the theater in opposite corners. You still say your going to get a full 6db increase? I want you to actually try it out and see what happens instead of just saying you have.
Of course you'll say how much more you know that me blah blah but it's just the saleman in you talking lol
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ntrain42
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Post by ntrain42 on Mar 30, 2010 16:42:12 GMT -5
Can you see the problem ntrain? you keep stating this as what you are going to get every time you add a second sub. It's just not the case. You have no idea what someones room is setup like and you just keep stating it as an absoult fact when it's not. Lets say your getting rid of some nasty nulls in your room, let's say the room is 14 x 20 x 8 foot celings. you put 1 sub at the front soundstage and 1 sub in the rear of the theater in opposite corners. You still say your going to get a full 6db increase? I want you to actually try it out and see what happens instead of just saying you have. Of course you'll say how much more you know that me blah blah but it's just the saleman in you talking lol Nulls? WHat about reinforcements/gain?  If you can get rid of nulls, you can also gain frequency reinforcements too. SUbs on their own can pick up 6db or more gain a certain frequencies from natural room gain. By using these natural room gains from careful SUB PLACEMENT(and you can do that with a good rta/spl meter)you can easily place 2 subs in different points of the room and gain a natural broadband 6db response in output from the combined subs, regardless if they are together or apart. Check and checkmate. |
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Post by Deleted on Mar 30, 2010 16:52:39 GMT -5
urgh, your just babbling and calling checkmate. I bet you would have sold alot of undercoating at your used car lot lol
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Post by markus on Mar 31, 2010 13:11:23 GMT -5
1/3 octave analysers have enough resolution to localize any major dips or peaks. Frequency sweeps and spl readings help to fine tune and verify the results. Sorry that's not correct. I explained why and posted data that proves it. Do you need to see more data? This is what Toole ("Sound Reproduction") writes about using EQs to tame low frequency problems: "Equalization was always there as an option, but the lack of affordable and portable high-resolution measurements hobbled the efforts. Unsatisfactory results were widely attributed to phase shift or other nonspecifi c maladies supposedly introduced by the electronics. In the early days, the equalizers brought to bear on the task were often of the multifi lter “graphic” type—typically octaveor 1/3-octave-band resolution, which matched the resolution of the real-time analyzers used to make the measurements. Room modes can have very high Qs, as can be seen in the narrow spikes in Figure 13.9. We realize now that much of the problem with equalization was that the industry had been performing surgery with a blunt instrument." Best, Markus |
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If you can get rid of nulls, you can also gain frequency reinforcements too. SUbs on their own can pick up 6db or more gain a certain frequencies from natural room gain. By using these natural room gains from careful SUB PLACEMENT(and you can do that with a good rta/spl meter)you can easily place 2 subs in different points of the room and gain a natural broadband 6db response in output from the combined subs, regardless if they are together or apart. Check and checkmate. 