Best acoustics channel on KZread 😊

This has been very useful for me. Thanks 🙏🏾

Very helpful thank you

For a room with a 20+ foot ceiling, seems like you could make tuned Helmholtz resonators out of PVC pipes mounted vertically in the room corners. After mounting, they can be tuned simply by cutting down the pipe length until they match the room resonance. Stuff them with acoustic foam strips until they're full, and you have inexpensive tuned absorption thick enough to reduce bass resonance in the room's high-pressure areas. I wouldn't attempt this first, only as a standing wave suppressor after applying porous acoustic foam panels to absorb mid and high frequencies.

Thanks Jesco, these videos are always so helpful and informative. Regarding Helmholtz resonators: both Rod Gervais and John Sayers argued that building them with a slanted back (while also filling the cavity with porous material), and thus making the depth of the resonator variable, you can actually lower the absorption q and make them more broadband (they refer in particular to slat resonators). Do you have an opinion on this claim?

Thanks a lot!

Before watching the rest of the video, I just wanted to share that my bass traps are basically squares, or boxes but with fabric sides and filled with fiberglass. The sides are somewhere between 25 and 35cm, so let's see what I can learn or how I can improve my bass trapping situation.

Hi, I'm a big fan of yours, your videos are amazing. I'm not an acoustic expert but a great enthusiast. I disagree with you when you say that resonators are expensive and difficult to build. I state that the acoustic treatment with porous panels is essential, but in very small environments from 50-40hz downwards I don't find it particularly effective especially on decay. In my 3.2x4.6m room I considerably lowered the decay to 36hz (it seems to me -13dbspl) only with a diy tuned resonator paid for a total of 25€ and done in 10 minutes. I think it's an excellent result considering that the dimensions are 90x40x15cm. Let me know what you think

Hey Jesco have you had experience using two subwoofers to "control" bass?

Wow! Great stuff Jesco! Sure wish you were here in the USA! Can you talk about Home Theater and the use of multiple subwoofers please. I’m trying to learn from you and apply your teaching to my attempt to improve my Home Theater/listening room. My room is a dedicated room that is 14.5’ x 23.5’ x 10’ ceiling. Some guys here is the US are recommending using either 2 subs to help smooth out the response or even 4 being the best solution. It sounds like I can get the very best bass response accuracy with 4 smaller subs as opposed to 2 larger ones? I am new to this channel and your knowledge and information is just outstanding! Thanks! Tony

13:00 … I have 4 tuned traps, two at the back of the room, tuned to 40hz and two at the front tuned to 70hz. They are still “sniper like” and also have a “narrow Q” compared to regular pours bass traps. However, because the specific locations they are placed have pressure issues, they are extremely effective… at that specific frequency. To get them to work you have to play tone sweeps and (like a subwoofer crawl) find the pressure zones, then figure out exactly what frequency that pressure is, then build the trap for that frequency. Fortunately the free Amrok software gives you a fair idea where to look and at what frequency. All that said, I feel that for the size of them, and considering how small most peoples rooms are, they’d be better off with deep bass traps. My 40hz traps are 30cm deep! That’s big! Even very deep bass traps at 6-8 inches take up less space and look noticeably smaller.

@NathanOakley1980

Жыл бұрын

Using your advice from a previous video, I only used the tuned traps at the end of the process (may add a few more panels 😊) and I only used them in specific places where the regular traps simply didn’t have the low end capability the 70hz and 40hz traps have…. Also as you suggested, I ran out of space before fully treating 40hz (70hz is fine but porous absorption goes that low too) so, I probabley need two more 40hz traps and At best I can only squeeze 1 more in.

@dollhousehero7596

11 ай бұрын

Tuned “bass traps” accompanied with finding pressure zones, correctly placing them and a lot of space to sacrifice is really the only non active way to get some amount of low end control in a small rectangular or square room. 30cm to 38cm is about the thickness of a tuned bass trap I’d imagine would be effective but that’s going to cost money and you’d have to truly know what you’re doing to get results. I wouldn’t bother with broadbands for bass control. If you’re an audio engineer It’s always recommended to learn your speakers and how they translate..I also suggest learning your room and how it translates to other listening devices. Acoustic treatment done incorrectly will not solve anything and only result in changing the sound of your room. Acoustic treatment needs to be dialed in and there needs to be a general idea of what results you’re trying to achieve before room treatment. You need to know what frequencies to target, etc.

I recently watched an interview with John Brandt. He said to definitely have an air gap behind your panels, but to seal the gap. For example, a panel with 3” of insulation should have a 6” deep frame, so the frame sits flush with the wall, but leaves 3” seal air gap. He said this increases tge absorption, and lowers the absorbed frequency. Do you have any opinion on this?

Great summary of all available options. I think you forgot to mention Multi-layer Absorber which are far more effective. Roughly, Helmholtz resonator can be filled with a layer of porous absorber so as a layer of air in order to broaden the frequency range effectiveness.. but yeah, still difficult to implement

@ostrol1590

Жыл бұрын

Any design or resources you have come across for multi-layer absorption? Haven't heard much about them!

@pulDag

Жыл бұрын

@@ostrol1590 nearly every membrane resonance traps.

@dollhousehero7596

11 ай бұрын

Not worth the small returns unless you have a lot time on your hands, room space to sacrifice and money to spend. GKI Acoustic sells tuned membrane panels but the amount of bass control you’d get from that isn’t much. Invest into two or more subwoofers instead and take care of the first point of reflection. Corrective EQ and some ok studio monitors. Don’t bother spending money on expensive sound gear when you’re at the mercy of your room. I’d even go as far as to say to mix on some neutral head phones with a solid state transparent amplifier; AKG K361 or Sony MDR-7506. EQ the headphones to make them even closer to a flat frequency response. Andrew Scheps mixes on headphones unless he’s in a properly treated professional music studio. Mixing on monitors that translate well is difficult to do when you’re in a small room. Adding insulation to your room will not control low frequencies.

How can porous absorber bass traps be effective in room corners if they are velocity absorbers? Doesn't a fundamental frequency standing wave have max pressure/min velocity at the walls and max velocity/min pressure in the middle of the room?

@nicholasmullins3693

Жыл бұрын

I've actually been wondering about this myself. I wasn't aware that sound waves sped up and slowed down based on proximity to a surface. I thought sound waves just moved at a constant speed and only amplitude changes as energy is lost.

@iEirikB

Жыл бұрын

@@nicholasmullins3693 It doesn’t change speed, that would also change the pitch. Velocity is not the speed of the sound wave, but how the sound wave moves the material it moves through.

@gregwilby3286

Жыл бұрын

By velocity I mean the movement of air molecules back and forth as the sound wave passes through them - not the velocity of the sound wave itself, which doesn't change. This movement causes compression and rarefaction of the molecules, like the peaks and troughs of water waves. Porous velocity absorbers impede this movement of air molecules. Some of the kinetic energy (loudness) of the sound wave gets converted into heat energy.

Which category do tube traps fall in?

Great video. Dennis Folley of Accoustic Fields is totally about membrane bass traps and says they are the only truly effective low end absorbers. Seems to accurate. Very expensive to buy. there are diy plans provided which save money.

@bluematrix5001

10 ай бұрын

Dennis is a Car Sales man

Diaphragmatic Absorbers belong to the membrane group, correct? Why emphasize the corners? Aren't room modes defined at two parallel surfaces, not corners? Assuming the goal is to effectively treat the low end, it doesn't make sense to me to treat a part of the room (corners) that contributes to around 10% of the problem. Maybe I'm missing something here?...

In your little chart you say that the effectiveness of room correction software is low. I couldn't more strongly disagree. Maybe you've just used really bad software, but in terms of improving and managing bass performance... Room correction software can be incredibly effective.

I have tested the PSI AVAA and it does work well, but I would say you need at least two and you need to experiment with the placement. I saw a significant decrease in low end ringing measured in REW back to back measurements on vs off. It brought the low end under control significantly - I think 50hz down to 250ms (with two) from 400ms off. This is also audible when listening to music. What they won't fix is nulls due SBIR or room mode cancellations. Unfortunately, they are very expensive and I don't really have enough room to fit them in.

@zerobject

Жыл бұрын

Thank you for a comprehensive feedback on the AVAA. Are they that huge, though? I always thought of it as of a more space efficient tool, unlike passive absorption or is it because you can't just put them simply in the corners?

@Pgreen3

Жыл бұрын

@@zerobject No not at all - but I have a very small room and the optimum position for them was at the back in each corner and the door occupies one of those corners in my room. I thought about only getting one, but it's not so effective. I found my REW measurement file and have sent it to Jesco. The best performance for me was at the back of the room in each corner. 50hz resonance was reduced from 475ms to 250ms - this is actually more than I thought it was. As I said before they didn't however do anything for fixing the cancellation I have at E2 to F2 85-87hz - I think this is from two room modes potentially - An Axial / Tangential mode at roughly similar frequencies. If I change to a bigger room I will definitely think about getting 2-4 of these, they are just a lot of money. 😱

@zerobject

Жыл бұрын

@@Pgreen3 Thanks again! Yes, Jesco also mentioned they are pretty helpless with cancellation, which is strange, especially for the money.

@Pgreen3

Жыл бұрын

@@zerobject No problem! Yeah I think for me I would need to shift my listening / speaker position. When I move listening position more into the central part of the room it flattens out the null I have - its just unfortunately not practical due to the room size. Potentially 3-4 AVAA's could help with room mode cancellations but have not seen anyone that many. There was one test I saw comparing an AVAA to a large passive absorber in an empty room which was interesting - just found it under Jochen Schulz's website.

@zerobject

Жыл бұрын

@@Pgreen3I rarely see them either. Actually, I noticed them in Ricardo Villalobos studio, but haven't asked yet, if they worth the money. He's always about breaking the rule, not to establish one. Wouldn't mind looking at that test too!

Personally I use PEQ for peaks, dual subwoofers for under 80hz, and 5 inch thick bass trips (with 5 inch air gap) with a range limiter to preserve treble energy. If I had to only rely on bass traps the acoustic size of my room would shrink drastically. I’m all about using multiple tools to balance cost and preserving space. The air gaps and PEQ are free for me and both make a large and measurable difference.

@ELISHACAEZ

Жыл бұрын

Bass traps should be 6 inches or more right? You might be missing some bass frequencies?

@seanb3303

Жыл бұрын

@@ELISHACAEZ i use a 5 inch air gap so that’s almost 10 inches thick effectively. Plus the range limiter takes absorption down even lower…having said that absorbers in general are very limited at frequencies under 80hz and that is why I use PEQ and dual subwoofers. It’s just not practical or efficient to have 4 foot deep absorbers to work on sub bass frequencies.

@ELISHACAEZ

Жыл бұрын

@@seanb3303 how does the active bass traps handle frequencies like that? The expensive ones that you have to plug in?

@ELISHACAEZ

Жыл бұрын

@@seanb3303 why does dual subs help? I always just assumed I wanted dual sub because I wanted to do stereo sub mixes I didn't know that it affected the room like that tell me more if u can bro

@seanb3303

Жыл бұрын

@@ELISHACAEZ Floyd Toole talks about it in his book. If placed properly they can break up bass modes. 4 is better but it gets expensive!

According to Floyd Toole: "At subwoofer frequencies the behavior of room resonances is essentially minimum phase". Thus PEQ is actually very effective: "It also means that both time- and frequency-domain correction is possible with appropriate equalization fi lters". Now this applies to a single listening position only of course. Do you disagree with this, if so why exactly?

@thotho7869

Жыл бұрын

Yeah seems accurate, using MSO on a minidsp with 3 subs did more for my decay/ringing in the low end than my 2 PSI Avaa active bass traps.

for cheap you need to add cheaper options like a mattress or a sofa, do they work to some extent right?

When building absorption panels, what sort of fabric should I use to wrap the insulation? I see a lot of more pricey fabrics with the “ acoustically transparent” tag, but I’ve also seen people say “if you can breath through it, it is transparent.”

@nicholasmullins3693

Жыл бұрын

If you can feel your breath through it, it is transparent. And honestly the worst thing you'll get with stiffer fabric is some high frequency reflection, which would really just help keep your traps from deadening the high end too harshly.

@nambams

Жыл бұрын

Pretty much. I've used burlap, canvas, cheaper poly linen, and expensive linen. If you can breathe through it, that means air can pass through it, which is what needs to happen if you want to slow the air molecules down by absorbing them. Just remember that there is a visual aspect of a studio if you want to have a place with clients over, so you want it to look good. Also consider how open the weave is because you don't want loose rockwool or fibreglass particles or strands getting out too easily. You also want to consider the level of flame retardant. Expensive fabric may have a degree of that.

@LBJedi

Жыл бұрын

@@nambams This was so helpful! Thank you very much😊

TubeTraps actually outperform anything, are very broadband and are cheap to make, but does not look as cool, very surprised are not in the list

If the room is so small that there are no standing waves, would software therefore work?

@radiczofficial

Жыл бұрын

Everything under 300 Hz that is problematic is a standing wave. You go into a toilet and you should notice standing wave around 100 hz, on the side walls. But from ceiling to bottom is still going to be around 60. The room you are looking for is only available for rats and bugs.

Good video on a hard to explain subject. I was stoked to see you included active treatment. Before I discovered that some people have created active solutions I had an epiphany and promptly designed and built an active solution for my 12x17 ft room. Before any treatment there was a 26db mode (a peak @34hz). Now I have pretty danged flat response from 20 hz up. My unit takes a feed from the preamp out and goes into a minidspHD and out to 2 crappy plate amps and 2 sealed boxes with 15" drivers. This setup is way far from flat, it would be nice to start with woofers that played flat as a starting point... in my setup the drivers are facing the rear wall and there is an inch of space from the driver to the wall. Delay and phase properly set and eq adjusted the system is really effective and the drivers are not audible when tuned right. The actual music feed is untouched and unaffected by this solution. The listening chair in this room is placed right where the giant null is located naturally, so to have flat bass response there (and the adjacent peak areas tamed) is pretty great IMHO.

I intend to treat my room and then slap sonar works on there for the sake of "It won´t hurt me with balanacing the system"

@dollhousehero7596

11 ай бұрын

You possibly won’t be balancing anything but you will be changing the natural sound of your room. If you’re into audio engineering this does not mean you will have mixes that translate well to other listening devices. Adding insulation to your room won’t achieve much unless done professionally. Bass control in a small room isn’t possible on a budget and you’d sacrifice so much space with insulation. 4 inches of fiberglass or rock wool on each corner stacked to the ceiling is not enough to control low frequencies and you can control mid to high frequencies just fine with furniture and a few broadband panels. Learn your speakers, learn your room, do some room corrective EQ if you want and forget about controlling low frequencies because even if you manage to change to sound of your room..that won’t equate to having a room that is suitable for mixing. If you’re just an audio enthusiast you can still enjoy your equipment with no problems but be wary of spending a lot of money on expensive monitors or subwoofers if your room isn’t professionally treated or designed to handle low end. I wouldn’t spend more than $1000 for a pair of monitors and no more than $500 for a subwoofer.

Thanks Jesco for another great video. I notice the PDF describes active traps as "extremely effective", but you have a ? next to their effectiveness in the video.

This second time Jesco mixed HH and Membrane traps: It's the otherway around. HH has range of one octave and membrane trap is either effective with very narrow Q or not so effective with very low Q. Hifi DIY crowd like to build drilled HH boxes as basstraps as they cost around 100€ and are easy to build. But you never see those in Pro studios as in large scale, slat resonators are better option than drilling million holes. But HH box style traps are definetly for home studio DIYers who like to, well, diy :) But as said: Its about one octave range, so not a broadband solution.

@digidope

Жыл бұрын

From the book of Rod Gervais; ..."is an example of a broadband slot resonator built into a corner in a room. This resonator is fairly broadband in nature and will handle frequencies ranging from about 66.44Hz to 155.82Hz. The estimated frequency range is based on the depths of the resonator-deepest point to shallowest point." Jesco: Do you say one octave absorbtion is narrow band?

great breakdown....what are your thoughts on VPR absorbers. Basically metal plates?

Important vid. I don’t think I, or anyone else really understand or understood how pricy it’s gonna be for anything worthy. Baby steps can work but really that’s more time spent across building multiple units across more spans of time vs doing it all in a single run. The whole process of porous absorption research and building was a very difficult learning curve from someone with practically no skills but it was beyond worth it and the effects are day and night.

my closet is ful of rockwool :D

Using absorbtion panels can't you tune the depth of the room's catch corresponding to the inches of deepness the absorption panel is and then also absorb or reflect specific frequencies on purpose with panel absorbtion membrane and reflection panels ext ext. Your Bass Trap video makes it seem like you can tune alot up in your room just by having those things. This is cool tho

Dennis Foley is not gonna like this.. 😬

Bass control isn’t worth it unless you invest a decent amount of money into your set up. Depending how serious you are about controlling low end frequencies in your bedroom your options may vary: 1. Furnish your room with bookshelves, a couch, a day bed, a rug, coffee table etc.. This is the least effective solution but at least you’ll have a nice room and reverberations will minimize. 2. Do number one but invest in two subwoofers or more. Use a room corrective EQ software and position your set up in the best place recommended(room aesthetics may be compromised) 3. If you have the money, invest into active bass traps. You’ll need one at every corner so prepare to spend $10k+ At the end of the day, truly controlling low end frequencies is not economically beneficial for the returns you’ll get. I speak to the layman and the enthusiast that is on a tight budget. It’s not worth breaking the bank just for “bass control”. Invest into furniture instead to deaden the room and a large area rug. GkI Acoustics sells decent 4 inch panels that can furnish the room but also help deaden the first points of reflection for mid to high frequencies. If you want any audible amount of bass control with acoustic insulation in a small room…you’d need to break the bank and cover the entire room in very thick rigid insulation. Some people have reportedly done this and STILL complain about bass control. Active bass traps is possibly the most effective way to truly control bass in a small room but those things are expensive.

Great info! Your videos should be half as long for real.

And what about multi subs?

How dare you to say Helmholtz are low effective?? I have absorption measurements that say otherwise. For the first resonances, perforated resonator are the easiest to implement, and the actual frequency will be the one that you designed. Membrane resonance traps are very effective, but the actual frequency is very hard to get, because of the building process. I strongly advise you to test more with perforated Helmholtz absorbers. Because they are the more cost-effective solution.

What about just not using bass traps. If you can’t afford it you don’t need it.

Tbh I like your content but I’m not going to watch 20 min of you just talking. Can’t you put this info on slides or show it while you are talking? It’s basically a podcast and there are way too many of those

Bruh all this dude does is talk

Another cool video Jesco