Ep. 27 - Bass killer! Boundary interference and how to FIX it | Speaker Setup | Home Theater Gurus
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- เผยแพร่เมื่อ 21 ส.ค. 2024
- In this episode we look at SBIR speaker boundary interference and how to fix it so it stops robbing us of upper bass. Speaker Setup . Home Theater Gurus
For room plans, building and design consultation contact me at @
Elitehomecinema.sales@gmail.com
1/4 wavelength calculator. Set to Hz, 1/4, feet or inches and sound in air. See video to see these settings set.
www.procato.com...
2" panels
ATS absorption panel 2"x2'x4'.
www.amazon.com...
ATS Decorative panels
www.amazon.com...
ATS 4" panels
www.amazon.com...
ATS DIY rigid absorption
www.amazon.com...
Recommended tools to see SBIR in room. Steps to measure found in ep 7.
Recommended tools
Umik-1
www.amazon.com...
Mini DSP 2x4 HD
www.amazon.com...
USB extension cables
www.amazon.com...
Bob Gold's absorption compilation
www.bobgolds.c...
Arqen SBIR article
arqen.com/acous...
More gold here, semi complex subjects broken down to simple easy to follow explanations and more importantly what you need to do to fix them. Had a dedicated HT for 6 years now and it has never sounded so good by changing things based on your videos
Thanks so much! Really love positive feedback like this!
Home Theater Gurus you ever heard a Procella audio speakers as front LCR in. HT, are they a lot better than hifi speakers such as svs or klipsch in a dedicated HT if there is not a requirement to listen at reference levels?
@@Stevo19801 no I haven't but I have a friend who designs for some big name home theater designers and they use them often. Them and Triad so yeah I know they are excellent with awesome on and off axis. They even have offerings for reference capable system.
This was very helpful. Ive got a killer dip at 125hz and I just ordered some panels to fix that up since moving the speakers wasnt an option. Thanks man. Your minidsp videos were also killer at helping me dial my subs in. Room sounds incredible now.
Great video! Two things I don’t think you mentioned: (1) SBIR off the side wall since many people have narrow rooms with mains pushed up near the side walls, and (2) surface area of absorb and how a single 2x4 panel probably isn’t big enough.
Thanks Eitan! Yeah there's always something I notice during editing that I missed. I don't do any prep and just kinda jump in front in front the camera and start talking. I'm so busy I get them in when I can. I made 3 videos Sunday and probably won't be able to do more for a few weeks as after work and weekends I'll be on a dozer working on our new house site. I can't even remember what the 3rd video I shot was about, guess I'll find out when I edit it.. 😂.
The 2x4 panel will be good for the upper modal frequencies but yeah at a point larger is definitely better especially.
As for the side walls the room treatment videos would cover those too as 2" panels with the angle of incident will absorb a good bit lower than the specs show. But I should have mentioned them.
I should have mentioned ceiling and floor too as possible issues but really for that I'd want to show measuring to confirm issues exist and I don't want to get too advanced unless I'm doing something where I'm actually measuring in room.
I really wanted to key in on front wall sbir to lead into the next video as they kinda go together.
I’ve learned so much valuable information from watching your videos, thank you and please keep it up
CLIFF HANGER EPISODE?!?!?!/!?!?!?! TUNE IN NEXT TIME!
Nah, I love this, you had mentioned "rear wall" with SBIR and I was going to ask about "large" rooms where my MLP is nearly 20 feet from the back wall, but then you immediately said "it moves the SBIR down to the subs" . . .so yeah . . .that question was answered. LOL!
When placing the panel to handle SBIR, do you put it directly behind the woofers, or off to the left/right since most speakers should be toed in?
Awesome video, Steve! Very helpful. I do have SBIR and did not know about this. Thank you for breaking it down for us. Now we know. When's the next episode 😁 ?
Thanks!
I shot it last week but it'll be a few days before it's ready. This weekend I'll be on a dozer working on the new house site.
@@hometheatergurus that's awesome! Thanks!
@@hometheatergurus Once you put panels behind the speaker for SBIR, are we considering the distance from wall to baffle or the panel surface to baffle (considering that some panels can be rather thick)?
I followed your REW tutorial to set up my dual subs but I could not figure out why my system sounded better at 100Hz crossover until this video! My mains are 36 inches from the wall, which puts it at 92Hz........Thank you! Both my subs are in the front btw...I've not seen anyone else talk about this. I was only looking at the crossover point as it related to bass management. Based on this, I think most people are probably running the wrong crossover for their placement.
Awesome. I love when science wins another one! Thanks for the feedback!
The front of my speakers is at about 22" from the back wall so I'm going to use your advice making some acoustic panels that I'll place behind the speakers on the wall to see if it improves the bass in my room, I also have an active subwoofer that I had to put at a 90 degree angle at the right side from where I'm sitting but I did put it higher than you'd normally do so the driver of the subwoofer is at ear height when I sit down, you can't hear where the bass is coming from if you close your eyes in my room so that's a good thing.
However when I stand up and walk through the room I do have a couple of spots where you can hear the bass way too loud and other spots where it's way too low and I would like to improve on that so it's more of the same everywhere, I know it's not possible in my room to completely get rid of the low and high loudness spots but I'm sure it can be improved and I'm going to take your advice and try out a couple of different things to hear if it makes any difference and hope it will improve a bit.
Thank you so much for sharing your knowledge so I don't have to listen to people's dumb opinions that do not help at all, your information is actually good and usable which is a great thing.
Being an EE you know of reference manuals. We in the sound world have one, called the Complete Audiocyclopedia or The Handbook for Sound Engineers. Check it out, it would a good tool to add to your bookshelf.
Thanks!
Fantastic video as always, very informative. Am I correct in my understanding below;
If I have my baffle around 30-32 inches from the wall, that’ll have my null at below 100hz. So instead of trying to absorb it, setting my crossover at 100hz would solve the problem?
Wow awesome video. Thank you for this wonderful detail put across in such a simple manner. Did the next video on fixing SBIR get posted ? You mention some trick to completely fix SBIR ? I used the information in Ep 11 on modal frequencies and did find a good spot for the sub, crossover level and seating position to avoid room modes. But unfortunately the ringing is still there on some low frequencies. I am now looking at room treatment based on your 4 part video and this one on SBIR. Planning to treat the back wall around the couch with 4 to 6 inch rockwool 40 kg/ m3 because, unfortunately given my room dimensions ( L x W x H at 14.65 ft X 12.6 ft x 98 ft brick wall ) I am seated close to the back wall. My speakers are HT series Genelec G3 and Genelec 7060 B sub, unfortunately only one Sub. On and off axis are excellent. Coming to my question, will treating behind the Sub with a similarly thick panel like the back, help fix the ringing. I can also look at similarly treating the ceiling if required. Is there any other option? Since EQ (Audyssey MultiEQ) my final step is not going to address the issue. I already did a basic run with Audyssey and got the Sub distance ( much larger than physical distance to adjust for the time delay etc done) also the phase and level of Sub was tested and set prior to that so no issue there. Sorry to be so specific, would really help to know what the possible solution could be?
Treating the walls will help but not much in the sub region but primarily in the subs harmonics which are upper bass frequencies.
Eq actually works fantastic on ringing as ringing is always present at peaks. Reducing peaks reduces how long decay is audible which reduces ringing.
Home Theater Gurus A big thank you for the quick response. Can you also let us know if you did put out the video on the solution to SBIR, that you said you would cover in the next video. Is that out or yet to come?
Let me guess. Front Baffle Wall ? So your speakers are essentially in-wall mounted thus the entire wall is the speaker baffle . Only problem is your subs will no longer be in the same place acoustically. Or your room dimensions will have changed as the baffle wall is now a new wall making the room smaller in length and will change the room modes.
When you do a full baffle wall you'll use that wall as the boundary so room mode calculations are based off of that wall. Of course the baffle of a speaker that's crossed to a sub can have a baffle large enough that no sound can wrap around before it's crossed to a sub so it doesn't require a full baffle wall.
I will say you're close but not quite on topic of the next video... but don't say anything else as you'll spoil it. :) How am I gonna get everyone to lose sleep waiting for the next video if we give it away here.. 😁
I'm going to have bass traps (9" of Roxul) in all four corners with one sub left front and other right rear.
How much breathing room do ports need to operate properly? Aren’t they designed to use the back wall for bass reinforcement? How close can the absorbers be to the ports?
I've designed subs for over 20 years and the rule of thumb is pretty much the same for all tuned enclosures. You need to be at least the port width (for round ports) away from a solid surface.
Using jbl L96, L112, celestion sl6s and psb b25.
I got dip from both speakers 702s2 around 50hz,about 30 inch from front face speaker to the wall...😵💫
Hi, thanks again for a great video and good explanation! So looking forward to every new episode since I’m learning allot from them!
Today I connected my MiniDSP 2x4 HD and run the gain matching all thanks to your earlier videos. Hopefully will make the alignment and eq tomorrow before running Audyssey and aligning the subs to the fronts.
A question on subs, I have two identical once in use but I also have a third one not in use (different brand but same size woofer) Is there any reason to use this one to? I don’t really hear much about three, it tends to talk about two or 4. Also if it’s a good idea to use it, where would I place it (the main two are 1/4 & 3/4 on front wall in rectangular room.
And since you are taking in wishes on what we want here are mine
1. Audyssey room eq app and how to use it in combination with the other ep 7+8 and 26.
2. A FB group would be awesome to talk about the topics of episodes and to help each other out in different stages of improving sound!
Once again a huge thank you for making these videos and sharing knowledge in a very good way to understand them.
/J
Thanks!
For the sub, I'd use especially if it can be placed to fix an issue.
As for a Facebook page. I've had one started for a while but never made it active. In the upcoming video I actually talk about it and the fact I'll make it active in the next few weeks and I'll like to it. So you read my mind.. 😂
Home Theater Gurus thanks for the subwoofer tips, will start with the two and see if there is a problem that the third may solve!
Good news to hear about the FB plans, think it will work great as a platform for questions, tips and help/encouragement, looking forward to join the group and as always looking forward for the next episode of Home Theater Gurus to air! Great work!
All the best /J
Congrats on your home theater series, highly informative! if i have a large room with a 65' TV is there any way to place my HT front speakers (FL,C,FR) BEHIND my TV using some kind of acoustic treatment. I like the looks of my OLED and i wouldnt want to go to a projector just yet...so i thought to make my speaker bed layer as its supposed to be, but to do that the fronts must be placed a few feet behind my TV....any thoughts?
Hello again, I hope all is well. Question about SBIR and my center channel. Due to the room size and barn shape (attic space of a Cape Cod) I mounted my CC above the screen. It sits on a shelf with the ceiling about 1 foot above it. I have about 3 inches more of space between the screen and bottom of the shelf. I was thinking of replacing the shelf with 2 mounting brackets that would sit lower and closer to the screen. This would also open the space below the CC since it will only be supported at the 2 points on the brackets as opposed to a full shelf. Just wondering if this extra work would/could make enough of a difference to warrant the change? Btw, the room is 18'x13'x7'.25. And this is a 7.4.4 system with 100 inch screen and two rows of seating. That's why the CC went above the screen.
Hi Steve, firstly thanks for an excellent informative program! Especially compared to similar programs where the people are obviously biased to certain equipment for obvious reasons. I just have a couple of questions... firstly what happened to episode 15 and also the episode where you were going to discuss the Denon remote app. Lastly, just some thoughts I had regarding doing speaker calibration with the Mic in the upright position. I was thinking the other day that testing the front and centre speakers makes sense but doing it for the rear surrounds and even ceiling speakers it doesn't. Shouldn't one perhaps mask the microphone at the back to simulate ones ears. The reason being is that I always have to increase my ceiling and rear surrounds to sound ok.
Thanks again for an excellent program! Christo, Cape Town. South Africa.
I haven't done the app episode yet and I discussed it in this video. I'll be doing sub design first then the app. I sold everything with the house 😂.
As for the levels of the surrounds go watch my episode on calibrating for Reference and tweaking levels and how our ears come into play. It's a recent episode maybe 3 ep sides back. From you stated above you'll find it interesting.
I was hoping to see how 4 subs placement based on harman such as in each corner of the room will affect modal room but you dont cover the topic. Thanks
See ep 11.
Thanks for this video! If I'm looking at 4' from wall for front speakers, the calculator is predicting SBIR around 70hz. Would I need to treat this with an 80hz crossover? What about with a 60hz crossover?
Great video! just a quick question: so a good speaker EQ is completely useless in fixing (or mitigate..) SBIR problem? Thanks
Thanks. Yep that is absolutely correct. We can't fix nulls because when we attempt to boost the frequency we also boost the reflection that caused it so it just gets reinforced.
Hi - how would you treat SBIR for on-wall speakers that are about 6" from the baffle to the wall?
thanks for the cliffhanger lol.
on a side note what do you think about VBSS? im thinking of building 4 of them, do you like this design? or should i go with something else (not above $400).
You're welcome.. 😜
The VBSS is a great design for the money. I'll be covering similar designs where you use a high sensitivity driver and Tweak box size and tuning and then some eq to get a really nice high output result. It doesn't go super low but it's got a ton of output where it counts and it's affordable. See the chest slam Video to see where the sub peaks are at.
Home Theater Gurus already saw all of your videos. Should I wait for your designs or just build the VBSS? I’m planning to start building tomorrow.
@@Azzy_Mazzy go for it! It's a very fun sub. I'll be showing how to design a sub and be comparing different drivers and alignments but I'll most likely be doing a 3 to 3.5 cubic box tuned to around 20hz with a um12 for the build.
Home Theater Gurus thanks for the great content my man.
Home Theater Gurus where should the subs be aiming at if you corner load them? At the center of the room or at the corner or just straight ahead on the side wall?
Really great and informative video. I have a null in my front stage around 110-120 hZ, and with the distance to the wall I now assume its due to SBIR. I also have a false wall thats like 6-10" behind my speakers. Its just wood frames wrapped in fabric, so im also assuming the sound is traveling through the false wall and reflecting off the actual wall. At that frequency it seems its too high to raise my crossover, and too high to use a panel to absorb. I was wondering if i could put absorption in the false wall to solve this?
Yeah it'll be off the front solid wall. It could be front wall sbir or rear wall as explained in the 2nd half of the video. There's also side wall but if you've treated the room per the room treatment episodes that won't be it however it could also be floor or ceiling as well. We just went over the most common ones here. Also make sure you aren't sitting in a room mode.
Home Theater Gurus thanks for the response. The rear wall is treated as well as the sides as per your video. Would adding absorption in the false wall change anything? My thinking is will absorb some of it and whatever gets through would be absorbed again after it reflects off the solid wall.
@@danielwander605 its never a bad idea to absorb behind a false wall area. Enough insulation can help with modal issues above the subs for sure. We also use 1" behind an acoustic screen to absorb any high frequencies reflected back from the screen. But thicker is better!
Where do you measure the distance to when you have your speakers toed in so they are standing kind of diagonally from the wall? From baffle and straight back, or from baffle to wall in line with the speaker?
I got 50cm deep speakers so my distance from the wall will result in 113 hz ish. Whould this be any problem ? Should I put my speakers closer to the wall? Some distance from back of speaker to the wall is good isn’t it?
Use the center of the baffle (front of speaker).
@@hometheatergurus yes, but to which point at the front wall? Straight back or on line with the speakers angle of toe in?
I have SBIR at around 140/160Hz on my center speaker. What can I do with that? It's in front of the tv and I can't move it around.
Eq fix ,center channel sbir is easy to fix tbh
What happened to episode 28?
Do you have any recommendations for speakers around the HTM-12 price that are better? Because I’m not really interested in playing reference levels so is there a better deal?
Better will be hard to accomplish. I will say the jbl 3 series is awesome with stellar on and off axis.
Diy wise all the htm series is good. The fusion 8 is also extremely good but I'm not sure it's still being sold on diy sound group.
Also look into the Helix series. I'm a diyer and I plan on using those in my next living room.
Home Theater Gurus I haven’t found any measurements on the helix but it will fit what I need.
Home Theater Gurus also what do you think about DIYSG HT line?
So if you have drivers on the back of your speaker also should you panel behind them or does that defeat the purpose of having rear drivers. Thanks.
What frequencies are the rear drivers playing? Are they subs or is it like a Def tech with bipolar design.
If it's a bipolar and you have drivers front and rear playing the same frequency it won't have the same distance from the wall for both drivers so each will have its own distance to the wall and therfore its own sbir cancelation frequency.
Yes they are def technology bp7000. I probably shouldn’t do any treatment behind the speakers correct
Yes they are def technology bp7000. I probably shouldn’t do any treatment behind the speakers correct
Yes they are def technology bp7000. I probably shouldn’t do any treatment behind the speakers correct
Yes they are def technology bp7000. I probably shouldn’t do any treatment behind the speakers correct
Q. How to avoid sbir from the front wall
A. In celling speaker 😂
Great video as always.
What about a rear ported speaker, does the port contribute to sbir? Or is that just "air"?
And from what I gathered is it's fine to place the speakers closer the the front wall unless you have, or are willing to, place thick panels behind the speakers.
Hey in ceiling works great at the airport.. 😁
Rear port would be irrelevant here as this is based on baffle distance from the wall. The issues with a rear ported speaker (phase shift at tuning and being aimed at the wall ) will also be irrelevant because we'll be crossing to subs well above a ported speakers tuning.
Hello fellow members ive been facing a major problem that im unable to find the bass in my listening position. The moment i hit the back row the bass is 10x tighter the lower frequencies are audible aswell as felt but the moment i move in the front row, while standing the bass is audible and fine but the moment i sit in my perfect triangular position the bass is gone. I tried different speaker positions aswell as distances but the problem remains. If im facing bass nulling how to direct bass a bit forward? If i need bass traps how exactly will they help?
Attaching a small video of my room if im doing anything wrong please guide me.
Room dimensions are roughly 20ft hy 16ft
Thanking in advance
See the ep on room modes. That and or sub placement are the problem.
@@hometheatergurus there are no subs. Just a 2.0 stereo setup