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Post by Hexspa on Aug 28, 2018 17:19:41 GMT
www.roomeqwizard.com/help.htmlIt's not that hard but you do need to physically use it to learn it. Just download the free program, follow the directions with any mic for now, and when you're ready for the real numbers, buy a linear response omni condenser that's in your budget.
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Post by rock on Aug 28, 2018 19:48:12 GMT
That's great advice! Fire it up and use what you have already. It's a cool program but like Hexspa say's, you have to use it. After a short time, and you'll know when, you can get a real measurement mic and you'll be off and running.
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Post by Hexspa on Sept 1, 2018 19:26:57 GMT
Any update?
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lal
New Member
Posts: 15
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Post by lal on Sept 13, 2018 17:29:55 GMT
Sorry for the delay in updating the post. I just logged in to the forum, I will download the roomeq wizard and will try. I have got a usb mike from my Arcam receiver and it has Dirac room correction. I will try to use it. Meanwhile I was just thinking of trying this speaker position also before adding acoustic panels and traps. Let me know if you think this is an option worth a try.
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Post by Hexspa on Sept 13, 2018 21:04:14 GMT
Try a few different combinations before you make any mounting holes.
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lal
New Member
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Post by lal on Sept 13, 2018 21:09:28 GMT
Will try the both locations I mentioned. Best way is to install REW and take measurement at listening position and compare?
Thanks
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Post by Hexspa on Sept 14, 2018 19:45:01 GMT
Ya but take more than one measurement. I usually take two per point. Also try to measure different points like a four-point radius around your listening position, your speakers with mic on grille, and any other areas you might find useful or interest bearing. Additionally, measure any changes you make to audio settings like applied EQ, settings on your speakers, or locations of speakers, treatment, and large objects.
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lal
New Member
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Post by lal on Sept 16, 2018 23:11:34 GMT
I do have a decent mike (omni directional) which I got from Arcam receiver.
I will start to measure and check response at few points near my listening position suggested by Hexspa.
Thanks
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lal
New Member
Posts: 15
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Post by lal on Oct 24, 2018 15:20:15 GMT
Hi Experts, Sorry for the late response. I tried to understand how to use REW . I did some measurement and I am pasting the plots. Blue color curve is left speaker alone and red color curve is right alone and green curve is combined left and right.I couldn't figure out a way to rename the curves. I used variable smoothing and this shows plot from 20Hz to 300Hz. Please let me know your suggestions. Thanks
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Post by Hexspa on Oct 25, 2018 2:24:02 GMT
Glad to see you're moving forward. That full-spectrum response looks suspiciously slopey with the muted highs and exaggerated bass. Have you taken a close-mic capture of the speaker? That can help you see whether your mic or speakers are actually tilted like that while minimizing room coloration. Also make sure you don't have some weird 4.5dB/oct slope setting going on or anything like that.
We don't use any smoothing for bass SPL. I don't know what variable smoothing does and, even if I did, that you used it makes me unable to normally evaluate your graphs. Only use smoothing for your broadband measurement and even then just to level out your octave bands.
At this point I need to ask what we're looking at. I know it's your two speakers but I didn't see where they are, where the mic was, or whether there's any treatment happening yet. Let's clarify these things before proceeding. Thanks.
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lal
New Member
Posts: 15
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Post by lal on Oct 25, 2018 13:09:01 GMT
Glad to see you're moving forward. That full-spectrum response looks suspiciously slopey with the muted highs and exaggerated bass. Have you taken a close-mic capture of the speaker? That can help you see whether your mic or speakers are actually tilted like that while minimizing room coloration. Also make sure you don't have some weird 4.5dB/oct slope setting going on or anything like that. We don't use any smoothing for bass SPL. I don't know what variable smoothing does and, even if I did, that you used it makes me unable to normally evaluate your graphs. Only use smoothing for your broadband measurement and even then just to level out your octave bands. At this point I need to ask what we're looking at. I know it's your two speakers but I didn't see where they are, where the mic was, or whether there's any treatment happening yet. Let's clarify these things before proceeding. Thanks. Thanks Hexspa for your reply. Sorry for not being clear. I have only two speakers and measurement taken at the most listening position. Speakers are separated by 8 feet and listening position is 8.5 in an isosceles triangle. Speakers are positioned in the same place as in the picture I initially posted but speaker position slightly changed ( few inches) based on trying different distances from front wall ad side wall. Speaker is with no toe in or it is parallel to front wall. I am not sure if that is the reason for muted highs. I am using the usb mike I received with Arcam AVR and I used the mic calibration file received. I am placing measurements without any smoothing. Blue color curve is left speaker alone and red color curve is right alone and green curve is combined left and right. Please let me know your thoughts.
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Post by Hexspa on Oct 25, 2018 19:01:51 GMT
60Hz and 120Hz are the peaks resulting from your room's two 20' dimensions while the spread to 140Hz is from your 8' ceiling. While that's easy, I don't know why you have a 9dB/oct slope above 5kHz. Assuming you figure that out, broadband absorption will probably help smooth your midrange peaks at 320Hz, 650Hz and 1200Hz. Something at 6.5' or maybe 3.25' gives you the bump around 180Hz so I'm guessing that's some kind of positional boundary interference.
You can try taking measurements closer to the speaker to see if the response is in-built to the mic or speakers. I think I already suggested this. If you haven't or won't do that, maybe you need to reconsider your positional arrangement to sit closer as that may help you get a better balance. Also try toeing in the speakers since high frequencies are directional. Maybe all that comb filtering, which is normal in an untreated room, is bringing down your average.
The most important thing you have to do is get treatment into your room. You don't have any yet, right? If you build it yourself, expect to spend at least $300 to get started. If your ambitions are more lofty and you want a room that conforms to decent standards, you might need to triple that. This is my first consultation and it's free so feel at liberty to get a second opinion on the exact cost-to-performance ratio. We need to see how broadband treatment effects your response before proceeding. After that, there are some possible EQ solutions you can try. I don't think trying to EQ before adding treatment is the right course of action. Thanks.
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lal
New Member
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Post by lal on Oct 25, 2018 20:48:48 GMT
Thanks a lot for your time and detailed reply, really appreciate it. I will figure out the 9dB/octave slope above 5kHz. Even I am surprised with muted highs. As mentioned I am using usb mike and calibration file from Arcam and not umik-1. I will do a measurement closer to the speaker and will sort the issue. Can you please give some more details about your statement about "Something at 6.5' or maybe 3.25' gives you the bump around 180Hz some kind of positional boundary interference". I want to understand that.
I dont have any treatment yet in the room .I am interested in doing a decent treatment since I am in a rented apartment.
As you said EQ may be the last option and I would like to do broad band treatment first.
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Post by Hexspa on Oct 26, 2018 3:02:40 GMT
Thanks a lot for your time and detailed reply, really appreciate it. I will figure out the 9dB/octave slope above 5kHz. Even I am surprised with muted highs. As mentioned I am using usb mike and calibration file from Arcam and not umik-1. I will do a measurement closer to the speaker and will sort the issue. Can you please give some more details about your statement about "Something at 6.5' or maybe 3.25' gives you the bump around 180Hz some kind of positional boundary interference". I want to understand that. I dont have any treatment yet in the room .I am interested in doing a decent treatment since I am in a rented apartment. As you said EQ may be the last option and I would like to do broad band treatment first. As you know, every frequency has a wavelength. When a two large boundaries, like parallel walls, have a 1:1 or 0.5:1 distance ratio of a frequency's wavelength, you get a resonance. When one boundary is 1/2 wavelength away from a speaker or your listening position, you get constructive interference. When the boundary by your speakers does it, it's called 'Speaker-Boundary Interference Response' or SBIR and when it's your head and a wall, it's called 'Listener-Boundary Interference Response' or LBIR. This is why it matters how far your speakers are from the wall, in the case of SBIR, and how far your ears are from a large surface for LBIR. This also works for nulls with odd quarter wavelengths like 1/4, 3/4, and 5/4.
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Post by Hexspa on May 10, 2020 3:34:30 GMT
Lal, I'm going to make a video on acoustic analysis. Hopefully it's ok I use your room as an example of what multiple dimensions will do. This should help a lot of people. Thanks.
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