Subwoofer Radiation and Placement, does it matter?

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[@andreemilsen369]

Too loud??? No such thing😛😛😛 (as long as it does not hurt, or the sound is distorting though🙊) Always something interesting in your videos. I thank you for your time and effort. 🙂

[@PoesAcoustics]

Hah…I’ll admit. I’ve heard systems that were just too loud. Some of the top systems being put togehter for demos and shows are so overpowered that when you actually turn them up toward their limits, it’s just way beyond healthy. I’ve been driven out of a room before. And of course distortion is the enemy of a good demo. Our whole goal should be to develop systems with headroom above and beyond what is needed. But I actually think many don’t know what the initial onset of compression and distortion sounds like. Most would recognize gross levels of distortion. But not small to moderate overloading. It’s still a bad sound. But many don’t realize what it is. They think that the pain from listening is because it’s too loud. Often it’s because it’s too loud for that speaker. One of the demos at CEDIA put on by one of the major brands was played way way beyond the limits of the speakers. I think they tried to keep up with the big rooms. But their speakers were simply not up to the task. Plenty of people were wowed by the demo. All the experts were not. Walking away cringing.

[@andreemilsen369]

@@PoesAcoustics Joking aside, I do agree with you, that there are times when I have felt things to bee too loud. Most of that time, has been because of distortion or room overload (when the distortion is not the speakers, but the room making too much noise). I am no expert, but my ears are good, and I think maybe I do hear the onset of distortion easy, what would you say it sounds like? If you can describe it? (Got me curious now🤪) At shows, I often find that I think rooms suck, when it seems many others do not. Like, room is filled, people dig it, I come in, and almost imeiatly have to leave....

[@HiFinest343]

If you had two subs but only one corner to place one of them in, would you corner one, or would you do 1/4 wall placement flanking the media center?

[@sagi_tech_n_stuff]

Try it and measure

[@waltmoody1664]

Thanks for all of the videos. I’m going to be installing for Martin Logan dynamo 1100s in my theater. I’m planning to align the subs using a mini DSP. Would you recommend the model with XLR inputs or single ended inputs? The room is 12’ x 14’ so the cable runs will not be exceptionally long.

[@PoesAcoustics]

Xlr

[@BobbyBass-x6i]

Thanks for the video. Always interesting. I started subscribing. Rock on!

[@PoesAcoustics]

Thanks for the sub!

[@L3x4Pr0ne]

Let this be a lesson. With respect to sound isolation, unless you’re fully prepared to go hardcore and spend a lot of money on the details, you’re better off timing your loud theater experiences to when your spouse joins you or they’re out.

[@PoesAcoustics]

I am confused. Lesson to who?

[@FOH3663]

Just in general. I don't think any disrespect was intended. Especially wrt simply isolating against thumping LF from migrating into adjacent spaces. That takes mammoth brute force effort of best practices, accompanied by attention to detail.

[@PoesAcoustics]

@@FOH3663 but I am an industry professional in sound isolation. I design state of the art sound isolation walls every day for dozens of projects. I know what it takes to stop sound. I didn’t go as hardcore in my room as I would for a client but I still have tons of LF isolation. I am able to watch movies full tilt without bothering or waking anyone. I hope he wasn’t suggesting I need a lesson in sound isolation. That just seems like a presumptive comment to make in a situation like this.

[@FOH3663]

@@PoesAcoustics Not presumptive at all. It would appear you're both in agreement, ... one needs to be fully committed with time, money, and attention to detail.

[@PoesAcoustics]

@@FOH3663 but then who was this a lesson to? It came off as a comment to me? That’s the confusion.

[@paultravisano9403]

Would these details matter for low frequencies? I'm isolating a basement theatre from my family on the second floor. Thanks Matt!

[@PoesAcoustics]

Which details in particular are you referring to?

[@paultravisano9403]

@PoesAcoustics Any treatment to the outlets. I suppose it can't hurt especially since it's fairly cheap. Kind of curious in general how small holes/leaks in the room will effect which frequencies will pass through. I used to design RF isolated chambers and the frequency was dependent on the size of the hole.

[@FOH3663]

Good luck, isolating a basement system from a second floor environment is no small task! Brief anecdote; At my desk/work bench in the basement of the Indianapolis Convention Center, two very tall floors below The Sagamore Ballroom, LF energy would transmit down through concrete columns down to my area ... it was rare, it was only the biggest rigs/shows. But yeah, unbelievable power of that LF energy. Good luck

[@alipazooki9297]

Hi, can you make a video about time aligning full range speakers and subwoofers together? I remember you saying that you use waterfall graphs to see if both the tower speakers and subwoofers are aligned but I’m not entirely sure how that works.

[@PoesAcoustics]

Not waterfall graphs. That wouldn’t do anything. I use wavelets. Yes I can show that.

[@alipazooki9297]

@@PoesAcoustics thank you so much!

[@johane7604]

Hi, great info. I have a question regarding sub placement for a solo listener. Is the advice regarding optimal placement also valid if you are using equaliser? Or could the corner placement be a better choice anyway if you equalise in the listening position?

[@PoesAcoustics]

For a single solo position you focus on subwoofer placement for that one seat. EQ is necessary but not a replacement for placement. The reason is cancelation dips. You can’t fill them through EQ.

[@davidjalsoviczky6055]

Awesome video, as always. I am seriously considering putting sealed subwoofers into the ceiling (firing down). You mentioned that when you put a subwoofer into a wall, it becomes hemi spherical and no longer a 360 degrees disperser. You also mentioned that quarter placing subs summon SBIR problems and losing the benefits of reinforcement from the surrounding walls. So my question is. If I want to put 4 subs into the ceiling, should I go with the quarter positioning, and if so, should I expect losing output due to the lack of reinforcements from the walls? I know that more subs are better for more consistent results in multiple listening positions, but drawback can be the lack of punch (except if you put all the subs to the corners), which was present when you had to focus to 1 listening position only. Is putting the subs behind the screen and thinking of an SBA or DBA is a better solution? If I put them behind the screen and basically into wall, would I face with the same issue, as no reinforcement from the walls? Can that be countered with more powerful subs? What is the best solution, if I want to keep the punch, but want more evenness across the listening postions? Can that be achieved with in ceiling subs?

[@PoesAcoustics]

Without the right processing a SBA or DBA is really hard to get to work well in a lot of rooms. First, while four can work with proper DSP processing to focus and aim the wavefront, four is rarely enough to create a planar wavefront up to 100hz. You likely would need 8+ to get there. I can’t answer your other question without the room. The problem is that I need to have the room shape and layout to determine what may be the best place. Quarter positions could work fine. What in ceiling subwoofer are you looking to use?

[@davidjalsoviczky6055]

@@PoesAcoustics Thanks for the quick feedback. SVS 3000 In-Wall. I saw the the amp can run 2 pairs, but then I will probably have problems with the DSP, as it will set two pairs at a time and can't EQ, Phase, check polarity separately for each pair. Room is a rectangle, 4 meter wide, 6 meter long and 2.3 meter high. I have checked the Harman room mode calculator. Listening position is almost in the middle - I have told the owner that it is not a good idea. There are dips at 29hz at the length and 43 hz at the width and 70 hz at the height. Currently he has 2 x SB4000 and I have managed to get a good response, putting them into the opposing corners, but now he is missing the slam that he had when both of the subs were at the corners at the back wall.

[@VIctorCarruyo]

Are you referring to cardioid pattern subs, as the rare kind, or open baffle ?

[@PoesAcoustics]

I believe I was referring to cardioid but I don’t recall what I said anymore. Certainly cardioid subwoofers are not common in residential.

[@andyv9365]

Thanks Matt good info.

[@PoesAcoustics]

Any time!

[@HammerThyme9]

Have you done many infinite baffle subwoofer installations? Would love to hear a video on IB subs in general from you. Thanks!

[@PoesAcoustics]

Never done one. Because of the kind of rooms I design. There would never be a scenario they would work. You can really do a sound isolated room with an infinite baffle subwoofer. I’ve heard them plenty of times. But it just doesn’t fit in my design approach.

[@HammerThyme9]

@@PoesAcoustics Thanks for the reply! I hear lots of people saying IB subs sound extremely clean etc. but in your opinion, do they really sound that different from a well designed traditional setup? Keen for your thoughts given you've heard both. Thanks!

[@Nicoleise]

About the outlets, do you guys not have "proper" wallboxes in the US? In Europe, we'd use something like KAISER 9069-03 for outlets, etc. in sound insulating walls.

[@CrimsonJR83]

The sub crawl is never an option when a UMIK is only $100. 😆

[@PoesAcoustics]

Hah well ok. You still would need to place the sub in the rsp and do a mic crawl.

[@texxhexxmm]

What you say about two subs midwall?

[@jimtoomey9522]

Wifey needs a white noise generator 😎.

[@PoesAcoustics]

That’s supposed to cover up a reference output theater?

[@FOH3663]

@@jimtoomey9522 I have a FOH engineer, colleague/acquaintance that set up a two cabinet destructive summation sub array, positioned nearby a monitoring mic, merely to destructively lower the dBspl the local authorities were monitoring, so he could elevate the mains spl ... to get away with playback at a higher more impactful level from the main system! So your instincts are right! I first encountered white noise background generator for office space about 35yrs ago, at an Eli Lilly facility. I thought very cool ... very smart.

[@johnlim7720]

Good thing in my HT room about 90% of the time I'm the only one watching so majority of the problems that involve having seat-seat consistency I don't have to deal with

[@L3x4Pr0ne]

I have a room that sits six and it’s full a lot…but it’s with my kids, my wife, my sister in law. They don’t care or even understand seat to seat consistency exists. It’s just folks like us. 😅

[@PoesAcoustics]

I hear this a lot. But I think they understand it more than you might realize. When I first setup my system, before I had implemented Waveforming, bass in the rear row was intense. It was 6-9dB hotter than the main row. My mom and dad watched a movie and mentioned the bass was too much for them. They liked everything else. I had my dad sit in the RSP and he was surprised how different the experience was. Then waveforming was implemented and now every seat is the same. No more issue.

[@johnlim7720]

@@PoesAcoustics Ya seat to seat consistency is a must in a home theater when you have family members watching with you but in my case I'm the only one using it for 90%-95% of the time. They don't enjoy the sudden burst of explosion's and rumblings of an action movie

[@johntibiatowski1077]

Couldn’t you use a putty pad as an outlet gasket?

[@PoesAcoustics]

You could. That would be very messy. The putty pads are sticky and relatively thick. I’ve done this in critical areas before. You can see the putty pad. I did this to my projector hdmi port. The outlet box and Smurf tube wasn’t done quite right so I added putty pads to the back of the metal outlet. You can see the putty pad at the side.

[@crazyprayingmantis5596]

If you've got 2 subs get them off the floor, preferably at different heights

[@CarlVanDoren61]

Rel wants sub to connect w floor 😊

[@PoesAcoustics]

I am not against this.