DML Panels - How far from the wall should they be?
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- čas přidán 12. 09. 2024
- 3D Printed DML build parts: www.typicalben....
Everyone knows you should pull your speakers out from the wall. But in the case of a DML panel, how far should you go?
I took a few panel measurements at various distances from the back wall to see how it affected the frequency response of the panel.
Of course there are considerations other than just frequency response - but that's what I'm trying to improve in my panels right now so that's what I'm measuring today.
That 50hrtz spike is panel resonance, has nothing to do with your room. If you could place your speaker exactly half a 50htz wavelength from the wall you could take advantage of dampening to smooth it. Otherwise put a crossover in and cut above 60 hertz
I would suggest you look at the decay curve. If the 50Hz peak is actually a room mode, you will see it decay very slowly. Also, look at the rest of the bass range on the decay curve. It is possible that bass is better with lesser distance because you may be getting a reflection off the wall. The thing is, that reflection will muddy your bass while making it loud which is not desirable. I would suggest putting a sound absorbing panel behind the DML panel and testing.
Great advice, thanks. I have just been reading about this measurement recently. I am in a new house now so I'll probably go back and do some baseline measurements in the new space and will consider all these factors.
Another excellent video, with measurements. Keep up the good work man, the numbers matter.
Cheers 🍻!
Another great video, thanks for all the hard work. Wish I had the talent to build the stand like you did. I've got mine hanging from the ceiling.
Hey Justin, thanks a lot! The stands actually came as a flatpack-type kit, although I did cut them down to size.
Very important video - Tech Ingredients had the panels at random distances or in the center of the room. My conclusion is that I'll put the panels close to the wall and cut everything below 300 Hz for the subwoofer to take over. Maybe even stereo subwoofers since this range contains significant channel separation info already. Did you try with sound absorption behind panels as well (wool etc)?
I haven’t tried with panels yet - as soon as I’m finished with my current build (hybrid design with woofers below the panel) I’m going to work on room treatment and will probably do a followup to this video as I feel I’ve learned a lot since recording it.
Dual subs is a great idea. My hybrids are crossed over at 250hz and it really does make the mids sound ‘cleaner’ now that they’re not doing the heavy lifting of the LF as well.
Mhhh, really interesting. Thanks for the information. You should try what happens if the panels a very close to the wall. Lets, say start at 2-3cm and the nin steps of 5 cm until 20 cm. The exciter of course should not touch the wall.
Thanks Jochen, I guess this was a pretty basic first run through but I would like to add some wall-mounted panels in my living room later, so I'll definitely revisit this in more detail and with closed measurements as you've suggested.
@@TypicalBenYT I’m also curious about closer to wall measurements. Finished my “standard” 2x2 inch foam board speakers a week ago and initially set them about 4inches from the wall. Sounded like crap, and I was feeling pretty disappointed with this experiment. On a whim a couple of days later I moved them 8 inches away - still pretty close to the wall and about where you took your first measurement - and was blown away. The entire sound field changed significantly. I don’t have any measuring tools (except the ears, of course) but I felt the overall response to be leveled out and heard clarity where before there was mush. Great work and am enjoying your vids. Those are definitely the classiest looking DMLs I’ve seen!
@@remingtonsteele5519 If you haven't already, add a sub.
My two 2'x2' panels had no imaging and depth until I moved them forward to 40% of the length of the room from the front wall. The outside edge of the panels are 10" from the side walls. No toe-in. This is the same position that I had my planars at. My sound room is dedicated, with base traps and diffusion, so your mileage may vary.
So just over half way from the middle?
I had an idea for making panels that someone might want to try.
Get some canvas paintings or blank canvas frames and some spray foam and fill the back with the foam.
The rest should come to you without further explanation.
Thank You for another interesting video.
Watching this, made me think back to a conclusion from a pro loudspeaker-constructor, Troels Gravesen. He tested a set of the classic 15" Tannoy Gold Monitor speakers and wrote: "The frequency response (FR) of these Tannoys looks awful! Why is it this doesn't leave this driver useless? I've seen FR from electrostatic speakers that look even worse and yet these speakers sometimes deliver the best of sounds."
The frequency measurement You've done is good work and brings another dimension to understand the sound You hear. So it is very usefull in its own right. When it comes to actual positioning, I think it is best to go with what You hear and find to be the best. So bring in wife/kid/friend/cat and make them move it slowly to different positions while You listen.
Eventually You can find the sweet spot with the most enjoyable sound.
I absolutely agree. The measurements can inform design decisions and help to understand what's happening but at the end of the day you should go with what sounds best. What's nice about this (not very extensive) experiment, is that the best result came at a similar distance to what my ears told me anyway.
I wonder if the 50 hz isnt Alternating current hum? In the US our current is at 60 hz and a poorly setup system will have hum. We tryto fix this with high quality cables to reduce RF and have all of the system on the same phase of power.
First thing that came to mind as well. Probably the amp is not correctly grounded.
Another great video. Can you discuss a little about the measuring equipment you used? I'm assuming it was some sort of laptop application for the measurement and tone generation. My apologies if you already specified that info in one of the previous videos. I did a quick browse of some of the comments and video description. Thanks again.
Sure, and no problem at all! I think I discussed in in my previous 'measurements' video but didn't put the details in the comments.
I'm using the REW software: www.roomeqwizard.com/
It's free to download and use and you can make a donation to the developer if you find it useful.
I have a Dayton IMM6 calibrated measurement mic. It's designed for smartphones but it works with my Surface laptop which has a 3.5mm TRRS jack.
@@TypicalBenYT Thanks!
An interesting test would be angling the panels both towards center and away.
I'm curious about what software you use for measuring?
Room Eq Wizard.
Before watching this I viewed your video showing how you made the panels and I'm wondering which panel you tested; the one where the exciter is placed in the middle of the panel or the one set at 2/5 - 3/5? Also to overcome the reflected waves could a sound absorbing panel be placed a small distance behind the DML panel?
This was the 2/5 panel. Yes you could do that although it would need to be quite thick to absorb a broad range of frequencies (low frequencies are particularly problematic).
Also I don’t think that the back wave is necessarily a bad thing, provided you have the space to set the panels up properly. In fact it has benefits as well.
Man, that's kind of confusing. I think you're seeing boundary reinforcement. And also some smearing with sounds off the wall combining with the direct sound of the panels. That 50hz peak is wild. You didn't really have that in your earlier measurements as I remember. Odd. Look for a distance between two walls that is 22.6 feet, don't forget about the hallway.
Hmm ok, thanks I’ll do some measuring. Have ordered one of those tiny digital amps off Amazon so I should be able to get an outside measurement soon too.
@@TypicalBenYT One thing to keep in mind is that you’re kind of in uncharted territory. Almost all other panel speakers are unbelievably directional, They are the most directional speakers you can get. DML’s are diffuse, they’re some of the most undirectional speakers you can get. And at least it’s claimed that they interact with the wall very differently than other speakers. So not all classic speaker theory is going to directly apply probably.
@@perrys2199 Yep good point.
@@TypicalBenYT Again, that 50 hz peak is bizarre. If you’ve got parallel surfaces 22 to 23 feet apart then that’s probably what it is. If you don’t then there’s something else causing the problem. I think it’s something else, in your last video your floorstanding speakers had a dip at 50 hz. They would have blasted a room mode like that through the roof. None of your measurements had a 50hz boost like that. I think there’s something else going on. You did have a smaller peak at 50ish hz with the close measurement but nothing like this.
@@perrys2199 Have just done some measuring in of hallway / back wall etc and there's nothing approximating that length. I'll have to adjust and measure a bit more to see if I can track it down I guess.
I concur with what OleTC said a month ago, to bring your wife/kids/cat/dog/sister/MIL to listen and chime in, but are any of them going to be sitting 1 meter in front of the speakers, no matter where the speakers are? If you were in an actual lab, testing the specific speaker response, 1 meter away would make sense, as it would take sound directly from the speaker panel, disregarding reflections. But that's not how you listen. If you are graphing speaker response in your living room, you are actually graphing the room, more than the speakers. So go to the spot in the room where the listener is going to be.
Thanks. I will be doing a room setup video later (In a new room) with these type of measurements. My aim here was to share the results of the panels themselves but as you've said it's a bit flawed in this configuration. I am working on setting up a better space for this kind of testing so hopefully I'll be able to obtain more accurate 'panel' results in the future.
OK, just a question, if instead if just mounting the panel on a frame like you do, what if you hang it in a box structure like a conventional speaker box without a front (your panel is the front) with an air gap right around the edge, maybe 2 inches airgap? I'm thinking it might also enhance the bass end so you dont need a separate sub.
Just use a separate sub and tune it to your panels, trust me your ears will thank you.
But you have DMLs, they do not work quite the same as typical loud speakers. I think your biggest acoustic problem is your walls, the room are bare of good acoustic properties. Of course we can only see the hallway, and that one wall and a light throw down carpet. Bare floors are a killer, sound wise.
It's an awkward room for sure. I'm in a new place now and will be setting up the space a bit better (as well as I can anyway).
Hello Ben.
Thank you for your efforts to measure ...
If I may, I would like to clarify a few points.
1. The material of your panels (I suspected that from reed)
2. Is it possible to make measurements, but yes - it is impossible - you will have to move the vibrating emitters from their places ...
But suddenly you have a superfluous one, Is it possible to take a characterization on such materials:
2.1 Plywood 6 - 10 mm thick
2.2 Double packing carton (This is when the paper layer is even + wavy + smooth + smooth + wavy + even)
Perhaps you have already done this.
Can you see the results?
Thank you very much.
Hey Alexandr I haven’t tried different materials yet.
These panels are made from a 3mm thick bamboo plywood called laserply. I am also experimenting with acrylic sheets.
I would like to do more testing of materials and shapes but don’t have much time at the moment. Possibly in a month or two I will be able to try more things out.
Looks like you want to be as close to the wall as you can get.
Maybe I'm being very naive but isn't it possible these days to make a digital graphic equaliser that would create a perfect frequency response graph from the ones that you have shown? ie amplify and attenuate 100 or more different frequency ranges as appropriate.
Yes that’s true to an extent. I’m not an expert but I’ve definitely seen such DSPs that can account for system imperfection and room acoustics and spit out what should be a near ‘perfect’ sound.
For me though I just enjoy tinkering and trying these things out. It’s interesting to see what simple changes like speaker placement have on the end result.
Could be way off here but think I’ve read that phase becomes a problem 🤷♂️
@@3888Orbost You’re probably right, but I’d guess a decent system would be able to compensate for phase issues too… I’ve never really gone into it though.
@@3888Orbost I thought that positioning 1 exciter dead center and the other in the 2/5 + 3/5 position helped with phase. The tech ingredients video on DML's takes a deep dive into this.
Interesting test but not nerdy enough to be very meaningful. You also need to test the panels at an angle to the wall.
Testing a single panel directly in front of the panel in a room full of furniture is almost a waste of time because it will give you almost meaningless data that doesn’t match the listening experience and it is not pure enough for clinical purposes.
To do a more realistic test of the room you need to set the microphone on a tripod in the position of your ears where you would be listening from. Then run the tests with one and then more speakers so that you can tune the room for best listening experience effectively.
To do a clinical test you will want an empty room with some sound absorbing panels on some of the walls.
It’s just intended to be a starting point for anyone who’s interested. I don’t have the setup or experience to perform a more ‘clinical’ test, and I’d think that setting up a mic in the listening position would be less useful as you’d be hearing MORE of the room acoustics vs the direct speaker.
Having said that I am moving house in a few weeks and hope to be able to conduct some outdoor tests there 👍