Acoustics, speaker placement, subwoofers

Discussion in 'Speakers' started by Riotvan, Jun 9, 2018.

  1. Riotvan

    Riotvan Snoofer in the Woofer

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    Put your speakers in the wall, the subwoofer under your chair or live inside a padded room. Here we can discuss anything related to placement and acoustics, feel free to post your problems, suggestions and experiences.
     
  2. Mkoll

    Mkoll Acquaintance

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    My new Adam T7V monitors were on my small-medium size desk and sounded good. I bought some stands, moved them about half a meter forward and to the right/left and wow, night and day difference. Now I actually understand what the terms "soundstage" and "imaging" mean because before there really wasn't much of one. And now I understand the enormous impact positioning has on speaker sound; seriously, it can't be understated.

    Now to figure out some EQ and/or bass trapping to even out my sub's frequency response. Unfortunately its positioning isn't as negotiable as my speakers...
     
  3. Thad E Ginathom

    Thad E Ginathom Friend

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    It is not a black art. Stereo triangle is a fairly simply thing to set up, with you at the sweet spot. Then you adjust for your room and your speakers.

    Having said that it is not a black art, there are people who seem to have a certain knack which goes beyond unconscious calculation of geometry and absorption/reflection. So... maybe... It is a black art! :D
     
  4. atomicbob

    atomicbob dScope Yoda

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    The SVS PC-2000 was my second choice. I couldn't fit the pair of Bag End D18E-R that I use in the corporate lab. WAF is very low with those. Driven with a Crown ITech-5000. When I play my recording of a Bell 206 at accurate sound levels, the campus building shakes.
     
  5. Mkoll

    Mkoll Acquaintance

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    I'm very happy with the SB-2000 I recently purchased. Granted, I don't have much experience with subwoofers, but this is the best I've owned by far. Bass notes are well defined with no muddiness, it extends really low, it can get incredibly loud (I'm less than 9 o'clock on the volume dial) but still adds great oomph at low listening levels, it has fairly precise phase control which is crucial for my placement, it's not too big or heavy, and it came with a free t-shirt. I'd say give them a shot. Worse comes to worst, they have a solid return policy.
     
  6. pedalhead

    pedalhead Friend

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    As @A1Gear mentioned, just yesterday I picked up a JL Audio E110 to go with my recent stand-mounted Dynaudio Special Forty speakers.

    I've only spent a few hours futzing so far, but it's already sounding pretty good. I initially tried to set it up with the speakers full range but with port plugs inserted which effectly gives them a pretty steep rolloff from around 90hz downwards. I was struggling to get a seamless xover between sub and speakers, so figured I'd try the subs built-in line level inputs and outputs which use a Linkwitz-Riley xover.... Pre-amp > sub line-in > LR xover > sub line-out > power amp.

    Unsurprisingly, this immediately sounded way more seamless & natural. It also has the benefit that neither my tube power amp nor my speakers need to deal with any low frequencies (I've set the sub xover at around 50hz 24dB/octave to preserve as much of the nice tonality of the speakers as possible). I was kinda concerned that the xover in the sub wouldn't be transparent with the full signal, but it sounds fine tbh.

    Anyway, point being that the "proper" xover in the JL sub is pretty decent to my ears, and certainly has simplified setup in my room. Obviously you could achieve the same thing with an outboard xover, but this is a nice tidy way to do it. My system is in the living room so placement options are limited. The sub seems to work nicely here though....

    20180610_083413.jpg

    The JL subs are spendy though, especially in the UK. This one retails for £1750 (I found this used for £700, which feels like a stella deal). Made in the USA so a better deal on new JL over there. Worth checking out SVS too as they have a great returns policy. Two x SB2000 would probably be great, as I bet would 2 x JL D108. In an ideal world we'd always have multiple subs, if nothing else than to smooth out a lot of the room issues (the bass response in my room with the single E110 is definitely variable depending on where you're sitting).

    I was pretty spoilt by the 2 x dual 18" infinite baffle subs a built at a previous house. Incredible things, but WAF of two big holes in the floor sucks :)

    2593.jpg 2594.jpg
     
  7. cskippy

    cskippy Creamy warmpoo

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    Do you have pictures of the floor above? I'm really curious!
     
  8. Riotvan

    Riotvan Snoofer in the Woofer

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    @pedalhead That veneer on those Dynaudio's is stunning! Very nice setup.
     
  9. pedalhead

    pedalhead Friend

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    Sure. The room was a wonderful acoustic space, although the bass would resonate with the suspended floor in interesting, ummm...kinetic ways during some action movies. No other tactile transducers required :). I used acro-props downstairs to alleviate a bit of it but honestly these subs if turned up too high could have flattened the building (a 300+ yr-old barn) pretty easily.

    As this is an acoustics thread, I'll mention that the entire screen wall was about a foot deep with rockwool & covered in acoustically transparent fabric. I also made a load of absorption panels suspended from the vaulted ceiling (which cleaned things up a lot, highly recommended in ceilings like this IME). Lots more pics here... http://www.blu-ray.com/community/gallery.php?member=shockabuku , and the UK site AVForums made a video about the room. I haven't watched it for years & it's probably rather embarrassing, but here you go...



    2591.jpg 2608.jpg 2601.jpg
     
  10. pedalhead

    pedalhead Friend

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    Thanks, yes the finish on these is gorgeous. Lots of strips of birch that catch the light in really cool ways.
     
  11. Riotvan

    Riotvan Snoofer in the Woofer

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    Watched the vid, what an insane setup that was!
     
  12. Riotvan

    Riotvan Snoofer in the Woofer

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    Your room being almost square is the main issue i see but there are so many factors. I would go for acoustics first and then look at a sub, did you contact GIK acoustics yet? They are very helpful from what i've been told. Also something i want to sort out myself is a nice measurement mic with REW. I think the GIK guys will appreciate that as well so they can help you better with which panels to use and where.

    You can also make your own panels which will leave enough budget for a nice subwoofer, the designs are quite simple really. A wooden frame, some nice cloth and rockwool of the right density. But that's up to you if you buy them GIK gives excellent advise, it's just quite a bit more expensive.
     
  13. Thad E Ginathom

    Thad E Ginathom Friend

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    this is the thing with acoustic treatment. It has to be on that sort of scale. Rugs, throws and curtains only contribute very slightly, if at all. Well-stuffed sofas and chairs may help more. I have, several times, preferred the sound in someone's listening room when sitting on the floor in front of their sofa rather than on it, with reflections from a rear wall coming directly to my ears.
     
  14. pedalhead

    pedalhead Friend

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    Indeed, ime sitting close to the rear wall isn't ideal due to reflection issues. Often tricky to avoid in a shared room situation though.
     
  15. Riotvan

    Riotvan Snoofer in the Woofer

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    It does give you a bit more low end though. When i had that setup a couple of years ago i put a 10cm broadband basstrap behind the couch, was quite agreeable. But ofc no waf to worry about then so yeah, ymmv ;)
     
  16. Thad E Ginathom

    Thad E Ginathom Friend

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    It can be better to sit close to it than a few feet in front of it. That way, anything reflected reaches you so quickly you don't feel it.
     
  17. pedalhead

    pedalhead Friend

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    I've generally found it muddies up the bass, but the reflection timing thing actually makes sense yeah.
     
  18. Riotvan

    Riotvan Snoofer in the Woofer

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    So started tweaking a bit again this morning, so far: filled up the speaker stand i use for the sub with sand and used some sorbothane to decouple it from the stand, and also added two more panels. ~130hz ish peak is greatly diminished and the low end is noticeably tighter. I put a big one behind the screen and speakers and one in front of a door to the right that i kept open anyway but it has a glass window in it. Now i can close the door if needed and still adress a reflection point to the right. The panel is on feet and easily movable.

    Very happy with the result, might hang up a panel on the ceiling and call it done...
     
  19. Ardacer

    Ardacer Friend

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    If you have dipoles or omnis, put them near reflective surfaces behind them, but 1m away. Sit close to them, and have the room behind you be open or diffusive. In such a manner reflections, which are full spectrum copies of original, could be even beneficial themselves.

    If you have typical box speakers, trying to deal with back/side waves and reflections should be beneficial.

    Sub bass is a different beast to tackle due to room loading, modes, and such.

    This is my understanding of the matter.
     
  20. Thad E Ginathom

    Thad E Ginathom Friend

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    I suppose my life has been rather limited to typical boxes!
     

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