almikel

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About almikel

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    Brisbane
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    Australia
  • First Name
    Mike

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  1. Hi Dave, I know I'm being lazy, and should drag out my copy of Cox and D'Antonio, but do Fractals have similar minimum listening distance limitations to QRDs? Also how deep is the panel in the picture? I'd like to put some on the ceiling, but the head height in my room is limited. cheers Mike
  2. I went back but couldn't find any link - could you post it again please? These look awesome Mike
  3. You've probably never heard a well sorted room, because you wouldn't say that if you had. Appropriately applied acoustic treatment is the best "bang for buck" upgrade possible for great "in room" sound. I'd prefer a "reasonable" stereo in a well sorted room over a mega buck stereo in a poor room every time. There's no point in spending big $ on gear if your room isn't good. But get the room sorted and you so appreciate all that money you spent on gear. Mike
  4. Obviously I wasn't clear enough - if you want to control the low end - start with treatment targeted at low frequencies - thin panels won't help, and only chop out high end. For some reason quotes across multiple pages isn't working for me tonight. Review your whole thread - I've said the same thing a few times now - focus your treatment on getting the bass right 1st, then deal with other issues. Keep your insulation for traps targeted for lower frequencies - minimum 100mm deep (200mm better). layering works fine. Once bass is under control, then look at other treatment... Mike
  5. REW is free, as is ARTA, Holm Impulse, etc - but I happen to be most familiar with REW. That depends on the mike - if it connects via USB it should be fine - if via XLR (standard mike connection) it may require phantom power and a sound card with phantom power will be required to connect to a laptop running REW No that's not REW, but another free tool available here: http://www.acousticmodelling.com/porous.php If you're referring to REW - not too many - but plenty of online help available to get going. If you can use your existing microphone then you're set... cheers Mike
  6. Very marginally, the dense side out will reflect more very high frequencies. Bass frequencies won't be affected at all (were you hoping they would be?) A quick sim of these panels on a wall (no gap) In a Home Theater room with carpet and other soft furnishings, panels like these won't help improve bass and only remove top end - this is not desirable.
  7. that looks quite good - freq response is lumpy, but decay/reverb for the room is good - reverb times are very smooth. You have what appears to be modal peaks just above 70Hz, just below 50Hz, approx 45Hz, and approx 25Hz - you could try some EQ on these - don't try to fix the dip at 65Hz with EQ I'd take a guess and say you don't have block/brick walls, but possibly a slab floor? Some broadband absorption targeted at bass frequencies would help smooth 100 - 200Hz - try that before EQ. cheers Mike
  8. link failed post some jpg's of your reverb times and Decay below 200Hz (RT60 tab and Decay tab in REW)
  9. well done! - I haven't tried any limp mass traps yet, and would be keen to see your results should you build any. IMHO some absorption working 100Hz - 250Hz is worthwhile also - rooms with rigid boundaries will obviously have more bass issues to deal with - some of those down below 120Hz where absorption gets too big, and membrane traps are needed. IME I've had good results with EQ <100Hz, with loads of absorption working >100Hz - at some stage I'll build some limp mass traps to try them out, but my lightly constructed room is very leaky <100Hz and EQ seems to do the job. Mike
  10. Cheers Gi, I get that, and on an interweb forum you get bombarded with different opinions and who knows what is good advice vs bad. I'm a lazy DIYer - I hate building something that doesn't do what I want it to do. I know we're on the interweb, but trust me, building any number of thin panels will do SFA if the bass in your room isn't under control first - you're just mucking around the edges with an elephant in the room. Do yourself a favour and reach out to some Perth members to run a measurement of your room currently and post the reverb times. Ask them to give you the MDAT file (assuming they use REW), and get REW yourself (it's free). I'd be gobsmacked if your room couldn't do with some treatment focussing on <250Hz - deal with this first before building thin panels. IME people apply treatment because "rooms need treatment", without understanding what treatment is required. Don't get me wrong - proper treatment is by far the best possible "bang for buck" improvement to the room sound possible - but thin panels won't achieve this, and just chop out treble. Mike
  11. Hi Gi, you seem to ask the same questions over and over again with good answers provided in between which you don't appear to read/accept If you make these panels they will not absorb any frequencies much below around 500Hz if placed directly on a wall - I call that too much HF absorption and no LF absorption Speaker cloth lets all frequencies through - it will depend on where you place the panels as to whether too much HF is absorbed - no LF will be absorbed with these panels if directly on a wall wherever you place them. Great idea, and will help - but I suggest getting the bass under control first I'm not sure what this means? None of the treatment you've discussed targets bass - but this is where you should start... Apologies if I sound like a broken record - I'm giving up after this post. All the rooms I've measured benefit from absorption between 100-300Hz - this is not achieved with thin panels. @125dBmonster has loads of treatment already managing bass - the panels he's making are icing on the cake - not the start of the process. Feel free to ignore my advice - it's the interweb after all cheers Mike
  12. hi Matt, I'm constantly in awe of your motivation to keep building stuff !!... ...so apologies for being picky, but those panels won't provide diffusion - even with the pegboard involved. I only raise this as the OP referred to absorption at 1st reflection points to provide diffusion earlier in this thread as per the OP's quote below I'm not trying to be a PITA - just attempting to keep the OP on track and not confused between absorption and diffusion. Nice build (as usual) by the way cheers Mike
  13. High frequencies travel like a light beam from a torch - with the speaker as the torch - any absorption in the path will absorb high frequencies. Below the "transition zone" of the room (typically around 200-300Hz in most domestic rooms), the room behaves like the inside of a bicycle pump - pressure rising and falling - and you have room modes based on the room dimensions that define where the peaks and dips are. Below the transition zone, physics tells us that the air pressure is at a maximum and air velocity is minimum at boundaries (walls). Velocity of air particles is highest and air pressure lowest at 1/4 wavelength away from a boundary (there's an inverse relationship between velocity and pressure). Absorption works as a velocity device - to work it needs to be placed in areas of high air velocity. Velocity at a boundary is theoretically zero. This is why gapping of absorption (away from the boundary) is recommended. But from a pressure perspective, bass collects in corners - a tri-corner has 3 boundaries - all with a pressure maximum. This is why you target corners for bass trapping - but if using absorption (a velocity device) you need to gap it (eg straddling the corner) so the absorption is placed where velocity is > 0. For bass control, all corners work the same - wall/wall, wall/floor, wall/ceiling. If you apply absorption that targets bass frequencies first (ie straddling corners), you avoid any 1st reflection points, but still soak up treble from secondary/etc reflections. It's at this point you would determine if your room is "too dead" and apply reflective surfaces to the existing absorption (the bass will not "see" the reflective surfaces and continue to be absorbed), or apply additional absorption or diffusion as required. As I've mentioned above, any remaining bass issues <100Hz are best dealt with via EQ, unless you want to experiment with tuned "pressure" traps - this is a different topic. cheers Mike
  14. Hi Gi unless your room is extraordinarily leaky in the bass end, some absorption targeted at lower frequencies should be considered. Cleaning up 100Hz - 250Hz makes a very big difference to the sound. as PTG mentions - measurements are helpful in this regard - you want to target even reverb times across the frequency bands, which gets harder below 100Hz. Too much absorption will reduce high freq reverb times too much - which is where covering the absorption with strips of something reflective helps. I agree with PTG regarding staying away from 1st reflection points, depending on the off-axis response of your speakers (Peter's reference to how decent your speakers are). This doesn't apply to ceiling and floor 1st reflection points - absorption is fine for these (eg thick rug on the floor). I agree with this approach, but based on the rooms I've measured, I'd be surprised if there wasn't some control of bass required. If you put thin panels up (which won't absorb any bass), then decide to add more absorption targeted at bass frequencies (we'll call them bass traps for simplicity), that's a recipe for a dead room. Assuming your room isn't a bass sieve, ie it needs some treatment to manage bass, I would target initial absorption to get the bass under control - once this is achieved, the overall absorption of the room may be sufficient to have managed "echo, reflective sounds, cleaning up sound". This is just my opinion, and every room is different, but most media rooms don't have lots of hard surfaces to reflect high frequencies (tiled floors, lots of glass) - but they mostly still have bass issues. IMHO get the bass right 1st then look at other treatment. The approach for applying absorption to manage bass frequencies (say 100Hz - 250Hz) is quite different to the approach for applying absorption to manage an overly bright room - but if your room is both (ie it has bass issues and is overly bright), you may find that after managing the bass, the room isn't bright anymore - and this is when adding reflective strips to absorption may be required. Beware that once bass is under control, it becomes addictive, and the typical poor bass response in cinemas and live venues will disappoint - but you will grin like an idiot each time you listen to your system. cheers Mike
  15. Double sided tape wouldn't come close to holding up Tontine Acoustisorb 3 - I assume Polymax will be similar... If you want it working effectively as low as possible you should gap it anyway - it's rigid enough to straddle corners. As I've mentioned above, apply treatment to get bass under control as the priority, which means decent sized traps straddling corners (and you have lots more corners to straddle than the four wall corners). Worry about 1st reflection points once the bass is under control - and you might find you're adding reflective strips in front of absorption before you've got the bass under control, and your room Sabine count (absorption) is taking too much treble out - hopefully by this time your bass is getting close....provided the absorption is well placed and large enough. Sidewall placement of absorption directly on the walls won't help manage bass at all, but will increase the Sabine count of the room - beware of the common mistake of too much absorption with none of it absorbing low frequencies - boomy bass and chopped out treble - the bane of every band practise room I've been in. To properly get the best out of room treatment, it can't be done by ear, and needs a measurement rig (microphone, stand, cable, PC, maybe a sound card depending on the mike). I'm a self confessed bass nut, but in the rooms I've treated and mucked with (mostly my own), once the bass is under control, the overall absorption in the room is quite high, and other treatment options such as diffusion come into play, where energy remains in the room. Thin (say <100mm) panels directly mounted on walls are a waste of time IMO unless you have a very bright room that's very leaky for bass (eg all 4 walls are glass) IMO having EQ ability below 100hz is essential, as absorption becomes too big to manage freq <100Hz. cheers Mike