Home recording studio in the attic.

#16

Thank you Endora for the information, everything you write makes sense, I followed the manufacturer's recommendations too much.
The distance of 1.5 m is probably not optimal.

#17

Yes, it only tells half the story. The Genelec setup guide goes into more detail;

Cheers,
Jennifer

#18

Hi,
so finally finished, we will publish the photos next week. I did preliminary REW measurements without any treatment (waiting for the delivery of mineral wool) with a Behringer ECM8000 mic (approx. 70 °) 2.5 m from the front wall. Speakers 1.3 m from the side walls and 0.5 (almost in contact with a sloping wall) - 1.4 m from the front wall by 10 cm. Smoothing 1/24, SPL uncalibrated approx. 72 dB.

#19

18-260 Hz

#20

Laco, could you attach the .mdat file, please? I know that people who can read and understand REW files prefer the .mdat to screenshots. Thank you.

#21

I don't want to analyze yet, the room has an echo. When I have the basic treatment I will send .mdat. I test how low frequencies behave, I move the speakers and the listening position. I have a fairly large table, I compared measurements with a table and without a table. I'm sending a few photos for an idea.

#22

Hello,
I am sending the m.dat file from the measurement after the basic treatment, bass traps, cloud, 10 pieces of panels on the side walls made of mineral wool 5 cm. The best SBIR is when the speakers are placed as close as possible to the front sloping wall. Mic Behringer ECM8000 (embedded calibration file), Steinberg UR44 sound card (calibrated). Measured approx. 75 dB. If anyone could look at it and evaluate it, I would be grateful. I don't think it's bad.

#23

I have had a look but I have yet to learn to understand REW so there is little that makes any sense to me. Sorry, Laco. Hopefully someone more knowledgeable can help.

#24

Hi Laco, and welcome to the forum!

Sorry to only be arriving on your thread so late, but hopefully I can still be useful!

Yamaha HS7 monitors rear ports not suitable for soffits?

Yes they can be soffit mounted. Almost any speaker can be successfully soffit mounted, if the right precautions are taken in the soffit design. The only ones that absolutely cannot be soffit mounted, are speakers that have active drivers on the sides, top, or bottom of the case. But ports and passive drivers are not a problem. Some speakers are hard to mount in soffits, because of their physical shape (eg, deeply beveled faces, non-rectangular cabinets with more than (or less than) six sides, highly rounded shapes, etc. But even then, it is usually possible. Even the famous Genelec "eggs" can be soffit mounted, successfully. The HS7 is not a problem, and can be soffit mounted.

The manufacturer recommends placing monitors 1.5 m or more from the rear and side walls.

... if the room is big enough, then the can be away from the walls, yes. But the room has to be quite big, and the distance greater than 1.5m. As Jennifer and Starlight have mentioned, the problem is SBIR. If your speakers are within a certain range of distances from the front wall, then the SBIR dip and related artifacts will occur at frequencies that are very noticeable, and very hard to treat. For small rooms, the best location is usually up against the front wall.

I don't want to analyze yet, the room has an echo.

That is the best time to analyze the room! When it is empty, untreated, and sounds terrible. That's when you SHOULD do the first acoustic tests... to capture the true natural response of the room, exactly as it is. Then you can use that information to plan your treatment accordingly. If you wait until the room already has some treatment, then you won't know if what you are measuring is due to the room, or the treatment... Then it is too late to know what the real problems with the room are. Always do your first REW test with an empty room.

I test how low frequencies behave, I move the speakers and the listening position

To do that properly, these are the two procedures you should follow for doing that.
How to calibrate and use REW to test and tune your room acoustics

The "walking mic" test, using REW

I have a fairly large table,

I would suggest that you replace that with a smaller table. As small as possible. The table can have a big effect on the acoustic response of the room, especially with things like early.early reflections, and comb filtering.

I'm sending a few photos for an idea.

When you do your REW tests, take all of the guitars out of the room. They produce resonances that can affect the response graphs.

I just downloaded your MDAT, and I'll take a quick look....

- Stuart -

#25

I also have an untreated room measurement, but I didn't want to put data from the untreated room on the forum, these are the screenshots posted above. I tested the SBIR distance of the speakers from the front sloping wall 0.5 - 1.4 m. I haven't treated the back wall yet, there are only bass traps. A drop of 180 Hz and a peak of 155 Hz are probably related to the length of the room (right speaker diagonally 3th harmonic?). I will draw a drawing of the position of listening, speakers and treatment. Thank you for any advice.

#26

Gilmour74 wrote:I also have an untreated room measurement, but I didn't want to put data from the untreated room on the forum.

Why not? The response of the empty room is nothing to be ashamed of! Look around the forum, and you'll see many people posting their "empty room" mdat files, because it is the most useful data set of all: it shows all of the major underlying acoustic response issues, and gives you the basis for designing most of the initial acoustic treatment. Without that, it's a lot harder to understand the room and suggest suitable treatment.

Anyway, I took a quick look at your REW data, and one of the first things I noticed is that there is large difference in frequency response between your left and right speakers:

That shows the DIFFERENCE in response between them. Where the curve rises above the 0 dB line, the left speaker is louder for that frequency. Where the curve drops below the 0 dB line, the right speaker is louder.

For typical home studios, there usually is a difference, but in your case the difference is bigger than normal. You have swings of +15 and -10 dB, which is a range of 25 dB.

It seems that your speakers are not set up symmetrically in the room. I would suggest moving one of them in very small steps in one direction (maybe 1cm or so, for each step), and doing a new REW test at each position, then comparing that with the previous measurements to see if it is improving. Find the best spot for that speaker, then leave it fixed in that location and repeat the "walk" for the other speaker, to see if you can improve things even more. Also try moving other things in the room, in small steps too, such as the table, instruments, other furniture, etc. It might even be that some of the treatment you installed is not symmetrical.

So, I would suggest that you work on fixing that problem first, then we can take a look at the other issues.

A drop of 180 Hz and a peak of 155 Hz are probably related to the length of the room

155 is modal for sure. Targeted bass traps should help with that.

- Stuart -

#27

A chimney measuring 1.2 m x 0.55 m passes asymmetrically through the room, see the drawing with dimensions. It probably causes differences in the symmetry of the reflections of the left and right channels. On the chimney there is an absorption panel hr. 50 mm slight wave see photo. I'm sending a few photos for a better idea. I'm going to take measurements according to the instructions even without a big table. Thank you for your support.

#28

On the chimney there is an absorption panel hr. 50 mm

That's a possibility, certainly. I would suggest using something much thicker than just 50mm on that chimney. With 50mm, you only get good absorption in the upper mid range and highs, practically nothing below about 1 kHz. In other words, then entire bottom half of the spectrum can potentially be reflected from that. I would suggest something like 20cm of low density insulation, at least. You might even want to consider putting angled hard surfaces on the front of that chimney to slightly deflect the reflections off to the sides, with the thick insulation covering that.

Also, your desk is not symmetrical! You have a large "wing" to your right, but nothing to the left. It is possible that the desk wing could be causing some of the symmetry problems.

I would suggest taking out as much as possible from the room, and setting it up as symmetrically as you can, then adjusting the speakers to minimize the asymmetry (as I outlined in my previous post), and once you have it as good as you can get it, then start bringing things back in, one at a time, and do a REW test after you bring in each item to see how it affected the symmetry, and the overall room acoustic response. Sometimes simple objects in the room can have surprising effects. Doing it like this, one things at a time, will help you understand the effects arising from each object, and help you decide if you want to keep it in the room, or not. You will probably also find that you can move problematic things around to different locations in the room, where there presence is not too much of an issue.

That's part of the "secret" to tuning problematic rooms: One step at a time, small changes in position, and many REW tests. Yes, it is slow, boring, and tedious, but that's the way to do it if you want your room to have the best possible acoustic response, as close possible to the specifications for control rooms, such as ITU BS.1116-3, or EBU Tech-3276. Of course, you are the one who decides how good you want your room to be! If accuracy is not important for you, then you don't need to go as far with tuning your room, as someone who wants extremely high accuracy. It is already reasonably good, with just a few issues that need attention, and it can probably be VERY good if you want it to be.

- Stuart -

#29

Thank you Soundman for analyzing the measurement and explaining the problems. It's an amateur studio, I don't need professional parameters. The room has its limitations, it will be used only for home recording, mixing. In the untreated back part of the room (behind the chimney) I wanted to install pyramid or barrel diffusers on the sloping walls, or on the back part of the chimney. Now I doubt it will probably not change the fundamental problems of the room and I should focus on the part of the room monitors-chimney. I still have 5 panels of mineral wool 50 mm and one panel hr 100 mm. I put the panels behind the monitors, but I didn't notice any difference in the measurement. Maybe it would help to put a 10 cm panel on the chimney at head height, monitors? I've already thrown away the big table. I'm going on vacation tomorrow, but when I come back I'll try various changes and measurements. If you still have tips on what to focus on and where to try to place the remaining panels or diffusers, I will be happy. The table is symmetrical (arched in front), did you mean the keyboard under the Pink Floyd flag?

#30

Gilmour74 wrote:Source of the post Maybe it would help to put a 10 cm panel on the chimney at head height, monitors?

It is certainly worth trying!

Did you mean the keyboard under the Pink Floyd flag?

Ahhh! It's a keyboard! OK. I thought it was a side table. It would still b worth doing a test without that in the room, to see if it is having a negative effect. If so, then try different locations for it, to find a place that minimizes the problem... or put another keyboard on the left side!

I'm going on vacation tomorrow, but when I come back I'll try various changes and measurements.

Great! I'll be looking forward to seeing that, when you get back. Have a great vacation!

- Stuart -

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