Pro vs. Consumer BASS Management. Which is right for you?

[@njrumenos]

We need a full in depth RT60 decay tutorial from you with options for controlling bass decay below 100hz and every other possible range that needs treating/controlling! Great videos by the way, keep it coming!

[@PoesAcoustics]

Yes yes, I keep getting asked for this! I totally need to do this.

[@nicholasvail8129]

Yes please -

[@Mo-tn1gm]

Question: can you make an instructional video on how to use REW for phase and time alignment between subs and mains? No matter whether we have dedicated spaces or just a family room, everyone who enjoys improving what we have might benefit from some additional instruction. Surely more than a handful of your 2.28K subscribers might be able to benefit from your experience and ability to pass on some wisdom. Thx.

[@PoesAcoustics]

yes I can and I know I need to. REW has some amazingly simple and powerful tools for this purpose.

[@TokeBoisen]

To take a load off Matt, the best tutorial for this I've found was from Obsessive Compulsive Audiophile, who has great videos with to correlating multiple subwoofers as well as aligning to mains

[@niklasxl]

nice to see you back on a more regular video schedule, hope your channel would grow since your videos are so informative

[@PoesAcoustics]

Thanks, my wife has really been behind this effort. She's been pushing me to get back onto doing videos again. I'll do more stuff for Gene too. Just needed to get some time back.

[@ChadAV69]

For what it’s worth, I’m an amateur music producer and you’re right. There’s really no standard when it comes to music production. Most modern music gets done in either a home studio or a hole in the wall studio. A very common way of mixing is getting a rough mix done on one medium (headphones, Studio monitors or something else), then going back and forth between headphones, car, laptop, iPhone, etc. and finding a rough medium. I don’t know anything about movie sound production but it seems like there’s a lot more standards for it.

[@PoesAcoustics]

Well yeah, just to mix in ATMOS you have traditionally needed to get the room approved and the information you submit to Dolby, that gets approved, goes into the decoder for playback. So....you can't do what you describe in your message for big budget movie production. Now, that doesn't mean there aren't small fry ATMOS facilities doing it differently. Dolby doesn't have the same standards as they used to and no longer seems to require anything to get the license to mix in ATMOS. I think it was seen as an impedement to more wide spread adoption. You still need their approval for playback however. A proper Dub stage would likely need to be certified. I am not an expert in this aspect of it, the studio designer has to submit the paperwork and work with Dolby, which I do, but often the actual requirements are defined by someone in the industry. I'll be brought in by someone from, say, Fox Studios. They already know what they need. My job is just to take the space and turn it into an acceptable studio, but they will tell me if it needs to contain a CP950A, to get approved, if it will be used for post production work, etc.

[@12P14D22C]

Could u elaborate more on how diffrent Systems to Replicate the Sound influence your work ? IPhone/ Monitor speakers / etc pp. I was under the impression that if you have a Real good System, that would be used to Master music. Linear frequency, minimum room interferences, Phase correction and just good speakers on top. Because thats the closest you can get to the Real "Sound Image " of whatever you record? And then the device used by the consumer Puts it own "style / flaw " on top of it?

[@Novilicious]

This was your best vid yet! I find this stuff fascinating, especially as the IMAX standard only does all channels full-range. Great content on the difference between pro and residential standards 😊 More is this ‘nerdy’ content plz! On that note, i have always found the dialogue was lacking in my home theater and after I added the REL 3-D home theater solution, which is to add a subwoofer to my center channel and run it full range. I have never been able to understand dialogue better. I don’t think it works for all channels, but I’ve been super happy with this being done to the Center channel. Note that I do not run LFE to this subwoofer it is strictly a center channel enhancer. I find it fascinating that this is what Dolby labs recommends in commercial theaters and mixing studios, but not in home/small theaters because of their smaller size. I did not know this difference in recommendations, but it fully makes sense. In my case, I love the middle channel info in destination of Smaug (the hobbit), and I’ve never heard it that clearly when I summed the bass to mono. I say try it and see if you like it.

[@PoesAcoustics]

That could be, it may have been that the center channel needed more low end support than traditional bass management was allowing for. Some speakers can't do sufficient output down to 80hz and actually need to be crossed much higher, like even as much as 200hz to get the distortion down. Maybe something like that was going on.

[@sudd3660]

i am just doing 2 channel, but i do recommend full parametric eq with 4 channels at least and separate bass boxes.

[@northeastcorals]

Excellent video, I'd previously heard snippets about most of this stuff before on other videos but I've never really understood how it all goes together & works until watching this 👌

[@JulioCSolar]

Great content as usual.... but, I also love quantum mechanics. The point is that if I try to explain the butterfly effect to my friends ( as far as I understand it) they'll all be mesmerized as to how it comes to affect our weather (hypothetically) Furthermore, if they are really paying attention, they will ask how can they translate this knowledge to their lives? As for me: can I understand the chaos theory deeply enough? In a nutshell: How can we (mere mortals) translate the benefits of your in-depth videos and the amount of knowledge into a practical application? I guess everyone here have (or can have) a laptop, a unifi microphone and REW. In-depth tutorials would extremely appreciated. Thank you Mattew! You really know your stuff. That's why I follow your channel for last 200 years. 🙂

[@JamesWilliams-gf8gm]

Great video matt. Keep up the good work.

[@PoesAcoustics]

Thanks!

[@njrumenos]

Enjoying the content, keep it going please!!!

[@PoesAcoustics]

Thanks! Will do!

[@Risandi_Pradipto]

This video answers directly what has been bothering me for some time regarding bass management. Thanks for the informative video.

[@PoesAcoustics]

Great! What was that? We covered a lot.

[@TokeBoisen]

Really enjoying your videos, very insightful. Fittingly I just saw a bit of a podcast yesterday re. whether mixing engineers or distributors of whoever are neutering their mixes in the LFE department for home-listening, and I'd love for you to talk more about that. It's a contentious topic and it's something that might be making people overbuild their theaters with regards to massive bass to compensate for a non-issue

[@bretbond]

Great video. Question/topic, if you were to build from scratch a cost no object room, what would the best size be for acoustical performance (L,W,H) and what setup in that room (x.x.x)?

[@PoesAcoustics]

First, thanks for the support, I really appreciate that. This is a tough question and I don't know that there is a single right answer. Moving up to a room that is TOO large also means a need to move up to speakers capable of A LOT more output. That rules out a certain type of speaker. I would argue that also starts to add compromises to sound. On the other hand, you really need to be 2-3 meters from every speaker in a system, so smaller rooms often place you too close to the surrounds and limit you to only one good seat in the whole room. In a huge room, the angle errors between seats is dramatically reduced, the distance to speakers is relatively similar, so you end up with a very large sweet spot, many good seats. How many channels I would do is also tied to the room. But I'll be honest, if money were no object and I could spend whatever, I would probably go large. Probably something like 48'x30'x20' or so. This has a good bolt ratio, a good distribution of modes, is large enough for a fairly large listening area. At the same time, it is not impossibly large either. At 28,800 cubic feet, however, it is large enough that we can no longer look at brands like Paradigm, Klipsch, Polk, Focal, etc. We also can't look at the big boys in that sphere like Kef, Revel, or Perlisten even. We are now talking about the largest options from brands like Grimani Systems, Pro Audio Technology, and Ascendo. For subs, eight 18's is no longer excessive, its barely enough. So do keep in mind, this system would have to be large. This would be large enough for four rows of seats and 5-6 wide. As for channel count, 19.20.10 or something like that.

[@bretbond]

@@PoesAcoustics that’s an incredibly insightful and thoughtful answer. Very interesting. Thank you so much for the reply!

[@FOH3663]

Agreed Cubes are king, go as large as practicable. Then build inward and incorporate 𝙨𝙞𝙜𝙣𝙞𝙛𝙞𝙘𝙖𝙣𝙩 𝙞𝙣𝙩𝙚𝙜𝙧𝙖𝙩𝙚𝙙 𝙩𝙧𝙚𝙖𝙩𝙢𝙚𝙣𝙩 between the outer shell boundaries, and the faux inside boundaries. .. ie., below the transition utilizes the full depth, all the cubes, ... then above the transition is scattered, redirected and diffused by the faux inside boundary. 𝙨𝙞𝙜𝙣𝙞𝙛𝙞𝙘𝙖𝙣𝙩 𝙞𝙣𝙩𝙚𝙜𝙧𝙖𝙩𝙚𝙙 𝙩𝙧𝙚𝙖𝙩𝙢𝙚𝙣𝙩 = custom design/build; hanger waveguide bass trapping, in addition to typical best practices. The theoretical cost no object room question ... on ideal dimensions; go as big as possible and work your way in. Render those criteria a non-issue with treatment and geometry.

[@pulDag]

Hi Matt, very interesting and divisive topic now understood. Thank you. REL is one of those who are advocating to use bass driver (subwoofer) under each speaker. Their intention is based on real idea which is not valid in home theater environment. Great to know the issue behind it.

[@PoesAcoustics]

I don't happen to agree with Rel's approach. Placing a sub under a speaker makes sense to enhance that speakers midbass, arguably. However, below 80hz or so, it really should be about the subs spread around the room or in an array.

[@doyleshafer]

Very interesting. Had no idea about Dolby pro environments.

[@PoesAcoustics]

Yeah Pro is totally different. I've come to understand it because I've had to fight a bit with Dolby to get rooms passed.

[@dungysphincter7974]

Thanks for sharing Matt.

[@bingdong8571]

Absolutely agree

[@ProfoundAV-123]

So Mathew are the individual subs used in the pro environment bass manage or are they fed the line level signal for each speaker. I actually follow the approach that the pro environment uses in that i have subs for each speaker in my theater and appreciate how the bass moves around the room.

[@PoesAcoustics]

The subs are bass managed. The bass management speakers operate from something like 40hz to 100hz. You can’t really just add bass modules and feed them a full range signal. The sound would be quite corrupted if no integration effort is made. The mains and bass modules could certainly overlap, but you still need to use DSP to fully integrate them. In pro cinema the Dolby CP950A has amazing DSP. You can do quite a lot with it. I wish that thing could be used with residential movies. It would be cheap by residential standards for its capabilities.

[@giovanni1269]

So how would you treat a smaller rooms how would you set up subwoofers in smaller rooms? Thoughts for your next videos. Thanks for the work you are doing.

[@PoesAcoustics]

How small are we talking? The term small room in acoustics has a specific meaning, any room under 1000 cubic meters is a small room, any over that is a large room. But I suspect most people here have a different meaning of that term?

[@giovanni1269]

@@PoesAcoustics room size about 14x15x8

[@giovanni1269]

Also how would you apply room gain on 2 seal subs? Hopefully you can help ( SVS SB3000x2 on a 5.4.2

[@brandonmccall9823]

Thanks!

[@bingdong8571]

Yes yes yes

[@FOH3663]

Answer to the shot caller on the back couch conundrum? the producer knob! Nice work.

[@PoesAcoustics]

Thanks much appreciated. Hot the producer knob.

[@Stevo19801]

What are the main difference between pro treatment vs residential treatment? You touched on diffusion what else is there?

[@o0OBillO0o]

The amount of money, test & evaluation to achieve the performance standards for professional audio mastering is tremendous. If you seek to re create that, bear in mind it’s more than 3x cost of all the electronics.

[@PoesAcoustics]

Assuming it is a well executed professional mixing space, they really do spend a lot more money on the room itself and the acoustic treatments than is common in residential spaces. They also spend the money to have the final room evaluated and verified (and would pay to fix it if it didn't hit spec). The actual treatments aren't necessarily better, they may be, but I use the exact same treatment brands in my home theater designs as I do in my professional designs, and the brands I use are the leading brands used in professional settings. But...I was actually alluding to something else. Pro mixing environments are often dead with virtually no reflections around the mixing desk. That isn't actually desirable, it is done because a mixing room is an audio microscope. They need to hear through the room into the recording so they can disect it. Find every little subtle problem and fix it. That doesn't mean the room needs to sound good or that the treatment approach they favor does sound good. In my opinion, that approach is not desirable. A listening room should be more lively than a mixing room traditionally is.

[@BobFrostV]

I'm just curious what may be best to put on the back wall when the couch is against it? I thought a big diffuser was the proper choice after seeing it used there in so many setups.

[@PoesAcoustics]

It is not the best approach in many setups. The problem is well known but it's use comes from copying studio designs. Thing is, it's a dumb choice for studios too. You do want diffusion on the back wall, but you can't sit right next to it. Diffusers have a critical distance. The critical distance is around 12 to 36 inches, depending on the design. In some cases its more, really deep and large QRD's may have a critical distance measured in multiple meters. So if the couch is right next to the diffuser, such that your head is right in front of it, your head sits in a really dangerous zone. The critical distance is the point at which proper phase mixing has taken place. Before that, the nearfield, there is not good phase mixing. Essentually you have a lot of strong random phase signals hitting your ears, they haven't really mixed yet, and it can cause a wierd phasie sound. It can also add serious comb filtering. The best solution is a thick absorber. That will attenuate the very strong reflection. In my room I do have a slat diffusers/absorber right behind the second row, but the second row is around 2' from the wall. I don't know that a slat wall is a great solution if your head is right against it. The GUD diffuser has a critical distance of around 6 inches or less, so that could be used behind your head in a lot of situations. I've not tried it there, but the designer has mentioned a good use for it. If you wanted to have more of a mix of absorption and diffusion around the area right behind your head, I would only do it using the GUD panel. I am not aware of any other efficient and effective diffuser capable of full phase mixing in such a short distance.

[@BobFrostV]

@@PoesAcoustics Thank you! I'll do as you suggest!

[@johndaddabbo9383]

Topic suggestion: (assuming there has been any further progress on the topic) I would love to implement one of these now affordable 98" TVs, however without first solving the Center speaker delimma (a single center behind a screen vs. a dual center speaker setup in an attempt to achieve a solid center image), I find that even with a 85" TV that a single center speaker below or above simply doesn't allow for a solid center image, nor proper panning across the screen. Do you see any hope of this being addressed soon, or must us who put Audio ahead of Video continue to use a Projector and ATS screen?

[@johndaddabbo9383]

Topic suggestion: (assuming you have dabbled in / solved this one) What's the best approach(es) for bass management of a 2.1 (or 2.2 / 2.x) stereo only setup using Stereo only gear, i.e. that therefore doesn't have a preamp with built-in bass management. Do you do mains full frequency and then a technique to blend in a Subwoofer (or two), and then what about Time-alignemmet and whatnot. Any ideas on how to best solve / implement this (short of using a AVR or Preamp processor as our two channel preamp). HELP: anyone know of a true two channel stereo preamp with full bass management and Dirac (or at least a robust manual PEQ implementation)... without having to go with separate external devices such as MiniDSP. Thanks!

[@pauledwards8721]

Based on your comment for a single mixed LFE channel for ‘small/medium’ (average home) rooms. Would you then say for movies that floor standing speakers aren’t really giving any advantage at all then? Some people say even though you’re crossing at 80hz etc it’s of course not an immediate roll off so you still gain some presence below that x-over point. Or do you find it just causes more complications to manage? I.e no real advantage over good quality bookshelf speakers? (Not counting 2ch listening or discussing expensive in-wall and their advantages) I guess you may gain sensitivity/SPL in some instances 🤔

[@PoesAcoustics]

Speaker size doesn't really matter. That isn't the deciding factor. It depends on the speaker. A lot of companies reserve their best technology and drivers for the top one or two towers. The bookshelf speakers often have lesser drivers. They also make the towers 3-ways sometimes, but the bookshelf is often a 2-way. So sometimes the tower will be a better speaker with more output even in the midrange and treble simply because its a 3-way design with better drivers. But...the core of your question is if the bass capability of a tower is better than that of a bookshelf. So...it's still complicated. A lot of speakers can't hit reference levels and there are two areas where we see issues. The first is right around 80hz to 150hz. If the speaker begins to compress there, it will struggle. A tower will do better there because its a wider bandwidth speaker. At least potentially. The other area we see problems is in the tweeter. And...that applies to any speaker type no matter what, so in that case, tower or bookshelf won't work. Gaining sensitivity is always a good thing, that much I will concede too. Because of less baffle step compensation, the towers are able to retain higher sensitivity and that means more output. In all seriousness, most speakers cannot achieve reference levels. In fact, quite a few can't achieve it at any distance. They simply cannot produce 105dB's even at 1 meter.

[@Tearial311]

Most confusing thing for me is making a really good house curve on MiniDSP. A walkthrough on that would be awesome

[@BobFrostV]

I like +15dB from 20hz tapering to +7db at 100hz to flat by 200hz, then flat or ever so slight downwards taper to 13khz.

[@sudd3660]

listen for yourself with a online tone generator, then adjust eq by ear so that it all sound evenly loud to you. then everything is accounted for and no need for microphone

[@chebrubin]

I thought Gene loved the AV10 directional bass and re-folding LFE into the main channels with his monster RBH speakers.

[@PoesAcoustics]

this scenario never happened. He didn't use the AV10 with his RBH speakers and he didn't use or say he loves the multidirectional bass. The AV10 was used in his family room system with the Perlisten S7T's. We both did not agree with the directional bass approach (and I'm the one who initially calibrated it).

[@chebrubin]

@@PoesAcoustics But there is some merit to Epcot Center and Disney world type cinema room settings with tactile type bass and directional bass that engages the seated audience in the room. Like a cannon ball blast goes off in the back of the room. Something that is directional and below the crossover.

[@PoesAcoustics]

@@chebrubin bass is non-directional and not localizable below a certain point. 80hz was chosen because it felt two standard deviations below the average frequency at which people can no longer detect direction. There has been argument for concussive effects and directionality but the research is far from extensive or conclusive. In fact he concussive effects research doesn’t really exist. As for your examples. Those are giant rooms by comparison. Small rooms behave much differently. And the problem with directional bass approaches is that they compromise the frequency response and seat to seat consistency in favor of a feature that is of dubious value. So I don’t agree that there is merit to it in a home theater environment. The directional cues largely come from higher up bass frequencies which remain directional in a good system.