3ll3d00d Posted May 25, 2015 Report Share Posted May 25, 2015 One thing I was just thinking about, though - the_dude2 said that the FoTP barrel roll sounded 'different' when he was here, like it was lacking, and I think the hypothesis was that the room null was sucking out the 30Hz considerably. But, looking at the 2LP graph on the previous page (where he was sitting when he was here) the null doesn't look that bad? So perhaps it's a distortion-reduction thing instead?? One to look at if/when I have time/ability... lol your 2LP graph has 30Hz about ~8dB down on the surrounding frequencies, the barrel roll capture is in http://data-bass.ipbhost.com/index.php?/topic/290-using-speclab-for-measuring-in-room/?p=4209and it's hot *exactly* where your graph shows that drop. Here's a rough pic to show Link to comment Share on other sites More sharing options...
SME Posted May 25, 2015 Report Share Posted May 25, 2015 - Level on the REW measurement pop-up window maxed at -3.0, Don't do this! In REW, the sweep level is the average level of the sweep relative to dBFS peak as opposed to dbFS RMS. In conversation, we say that a sine wave has a peak level that's 3 dB above its RMS average. However, that 3 dB is an approximation. The actual value is more like 3.0103 dB. The "- 3dB" REW sine sweep is actually clipped on each peak before it even leaves your computer. Don't ask me why REW works this way. Also, I'm with 3ll3d00d as far as trying to understand why you are maxing out the sweep levels. I personally run my sweeps at -13 dB in REW and -10 on the MV. These should come in at 85 dB if you are calibrated to 85 dBC using -20 dBFS RMS pink noise. Note that the extra "-3 dB" accounts for REW specifying sweep level as relative to dBFS peak instead of dBFS RMS. Link to comment Share on other sites More sharing options...
MemX Posted May 25, 2015 Author Report Share Posted May 25, 2015 Thanks for the input, chaps, it is always appreciated and (generally) understood at this end, I think I just have struggles seeing the bigger picture that's made up of all the details - so many trees, what does the wood look like? I'm going to go away and will have a read of the AustinJerry stuff on AVS as recommended by d00d (http://www.avsforum.com/forum/91-audio-theory-setup-chat/1449924-simplified-rew-setup-use-usb-mic-hdmi-connection-including-measurement-techniques-how-interpret-graphs-21.html#post_22823228) and hopefully get things clear in my head. It looks like the usual epic length of AVS threads so I'll make some notes of relevant stuff as I go through, to hopefully filter out the noise. It's no wonder people buy plug-and-play subs and never bother with EQing, none of this seems intuitive and I'm either getting even stupider or less able to absorb information as I get older... I just want to 'get it' and am fed up feeling like a fucking idiot because it doesn't click into place - I'm ever grateful for everyone's help in this and all the other useful threads here and elsewhere and want to maximise the benefits of my system, I just don't want to be one of those annoyingly dumb kids you just want to tell to go play in traffic because all I do is bug everyone else for help but never actually manage to absorb any of it. Half of me just wants to give up and just be happy with it - it sounds alright with music so "it'll do" if it has to. Anyway, off to bed here shortly as I've not been sleeping that well and I've got to be up about half 5 tomorrow morning for what will surely be a terrible week at work with everyone being off for school holidays, so I'll check back in when I have something useful to add. Thanks again, all, I'll get there in the end (maybe) and perhaps I'll even stop being a miserable bastard. Link to comment Share on other sites More sharing options...
3ll3d00d Posted May 26, 2015 Report Share Posted May 26, 2015 I'm going to go away and will have a read of the AustinJerry stuff on AVS as recommended by d00d (http://www.avsforum.com/forum/91-audio-theory-setup-chat/1449924-simplified-rew-setup-use-usb-mic-hdmi-connection-including-measurement-techniques-how-interpret-graphs-21.html#post_22823228) and hopefully get things clear in my head. It looks like the usual epic length of AVS threads so I'll make some notes of relevant stuff as I go through, to hopefully filter out the noise. you don't need to read the whole thread, that would be crazy! just download his guide and use it to get your basic setup working - https://dl.dropboxusercontent.com/u/78476446/REW%20101%20v3.92.pdf- rather than fiddling with assorted soundcard/mic settings. It really should be a case of clicking a few buttons and then getting going with measurements *if* all you're doing is getting some in room measurements at normal listening levels. Link to comment Share on other sites More sharing options...
MemX Posted May 26, 2015 Author Report Share Posted May 26, 2015 Thanks for digging the link out, I did have a read but I think I was going word-blind. I can't get it to download on this work computer but it's restricted to hell, so I'll try at home later! Link to comment Share on other sites More sharing options...
MemX Posted May 27, 2015 Author Report Share Posted May 27, 2015 Nice, 105 pages... that looks like it will be comprehensive enough even for a simpleton like me. Thank you again for linking to it, I'll abuse work's printer and have a read when I get home later Link to comment Share on other sites More sharing options...
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