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pete_mac

I'm a room treatment convert! An amateur's non-scientific tinkering with Polymax XHD

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I pinched this info from my 'system' thread in the hope that it might encourage others with moderate systems and tricky rooms to try some room treatments.

 

I recently moved into our new house with dedicated audio room. The room is 3.5m x 5.4m x 2.6m and during construction we added some 'upgraded' Bradford SoundCheck wall insulation. The room is carpeted but has no lounges or soft furnishings, and minimal hard furnishings.

 

I recently upgraded to some PMC GB1i small floorstanders and an audio-gd ES9018 DAC (NFB3(2014)).

 

Whilst I was happy-ish with the PMCs, I felt that the imaging and bass wasn't as good as I had expected. I realised from day dot that this room was pretty average acoustically given the lack of soft furnishings for absorption and hard furnishings for diffraction. There's a bit of slap echo, and I feel there is just a but too much reverb and smearing of the sound stage. The bass was a tad woolly at times. The PMCs were clearly being let down by the room. Coupled with my new audio-gd DAC, I wasn't 100% satisfied with the sound.

 

SOOOOO... with a tight budget in mind, I decided to tackle the room in a simple and cost-effective way. I managed to grab two charcoal/black 2400mm x 1200mm x 50mm sheets of Polymax XHD direct from Martini Industries at Ingleburn, south-western Sydney (15 minutes from where I live). 

 

http://www.polymaxinsulation.com.au/downloads/Polymax_MDS_Absorb_Data_Sheet.pdf

 

Martini had two sheets left over from a recent job, and were kind enough to cut each big panel into 3 x 1200mm x 800mm panels on their industrial cutter for ease of transport. All six of the smaller sheets fitted into the back of my Mazda 6 with the seats folded down, meaning I didn't need to stuff around with a trailer or van.

 

The pricing was dirt-cheap too - it worked out at $20 per 1200mm x 800mm panel! At this price, there's no excuse for NOT grabbing some and seeing what it does to your room. If anyone needs contact details, Ben Mentiplay is the bloke I dealt with at the Ingleburn office.

 

I chose the 50mm as the thickness suited my intended use as side and rear wall absorbers, as well as allowing them to be doubled-up to become XHD 100mm if I wanted to experiment with absorbers that performed better at very low frequencies.

 

A big benefit of the Polymax XHD is its stiffness. It will stand perfectly upright against a wall with no sagging. I could quite easily get away without framing these panels, such is the quality of manufacture and cutting. I will, however, do something regarding framing and/or covering some day so that they blend in better with the decor. 

 

Interestingly, the Absorb XHD is manufactured using the 'card and cross-lap' method which Tontine used to use for their Acoustisorb many years ago, before switching to the 'air lay' process which is faster but less consistent and results in varied density throughout the product. One SNAer has encountered issues with the Tontine in a professional environment and only uses the Absorb as a result. Apparently, the published stats for the Tontine product are also based upon the old product from a few years ago (cheeky!) rather than the newer 'air lay' product which doesn't perform quite as well. It's amazing how much background and technical info there is on pro audio forums out there.

 

I had a bit of a listen with some familiar tracks, and then embarked on some non-scientific panel placement. I basically replaced some of the temporary panels and foam squares which I had placed at the first reflection points on the side wall, and on the rear wall elevated behind the listening chair. These were thin panels and your typical acoustic pyramid foam which did help a bit with slap echo, but little more. I also plonked a panel behind each speaker (this space was previously bare)

 

Cue the music... and whoaaaa, what do we have here? The improvement in reverb and echo was clear from the get-go. Imaging snapped into place, and subtleties which were previously masked are now clear and distinct. The sound is more coherent. From what I can tell, these panels have struck a pretty good balance between taming the ills of the room, yet allowing it to sound natural and still a tiny bit 'live'. Measurements may tell a different story, of course, but I'm very happy!

 

This is as good as I KNEW my system could sound. Gone are my concerns about the PMCs not quite living up to expectations, and likewise, that lingering doubt in the back of my mind that the audio-gd ES9018 DAC was too bright and not synergising with my rig. It's not the gear... IT'S YOUR ROOM, STUPID!!  ;)

 

Colour me impressed! For minimal expense, the performance of this room has been drastically improved. One day I might arrange for it to be measured properly, but in the interim, I am absolutely stoked with the outcome.

 

Now... let's see what wifey says when confronted with these black monoliths!

 

polymax3_zps59eda251.jpg

 

polymax4_zps8efd3867.jpg

Edited by pete_mac

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That's a great price for a big result.

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Indeed, I'm stoked.

I can get off the 'upgrade' merry-go-round for at least a little while now, and simply sit back and enjoy what I have. I've spent $120 which could end up saving me thousands ;)

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What are you sitting on in there?

A bean bag?

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What are you sitting on in there?

A bean bag?

 

 

An Ikea Poang chair - very comfortable, and cheap as chips:

 

poang-chair__19488_PE104775_S4.JPG

Edited by pete_mac

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I'm surprised that 'er in doors hasn't filled the room with cushions yet!

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Colour me impressed! For minimal expense, the performance of this room has been drastically improved. One day I might arrange for it to be measured properly, but in the interim, I am absolutely stoked with the outcome.

 

Why not do measure it yourself. It's easy and the gear required is cheap. It will also take all the guesswork out of placement issues and you'll not only achieve the optimal result but in far less time.

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Why not do measure it yourself. It's easy and the gear required is cheap. It will also take all the guesswork out of placement issues and you'll not only achieve the optimal result but in far less time.

Yes, you're right. Being a tinkerer and a DIY kind of guy, any measuring will most likely be done by me. :)

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I'd love to hear my Silverlines Preludes in your room and hooked up to your setup Pete. I auditioned the GB1i's at CAV but was totally unimpressed with them and I also realise that it had a lot to do with the crappy listening environment they had me in(that nook at the back next to the stairs and office with every man,Jack and his dog walking through your session) but I also listened to some Monitor speakers with ribbons(200 gold gx?) and they were far more listenable in that environment than the little PMC's.

 

I went with the Preludes purely because of size and price as it turned out and I'm happy with them, but I recently got to listen to the GB1i's in a really nice system and in a reasonable room and also some Opera speakers about the same size which looked a bit like SF Toys(leather or vinyl sides) and the little PMC's blew the more exxy Opera's away, I was suitably chastened for my dislike of them originally and I now agree with my conscience that it was basically the listening environment that was wrong and possibly the Cyrus system running it all.

 

Which brings me back to wishing I could park my imports next to your speakers and have a good listen :)

 

The room is getting better isn't it and i like the way your just feeling it all out as you proceed down the road...softly softly catchee monkey as the saying goes.

 

WD :thumb:

 

*looking forward to next update.

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An Ikea Poang chair - very comfortable, and cheap as chips:

 

poang-chair__19488_PE104775_S4.JPG

bought one of these when we had our first (and hopefully only) little one. Extremely comfortable. Tunes + wine + chair = sleep :-)

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Cue the music... and whoaaaa, what do we have here? The improvement in reverb and echo was clear from the get-go. Imaging snapped into place, and subtleties which were previously masked are now clear and distinct. The sound is more coherent

 

 

How would you describe the changes (if any) to the soundstage itself? Regardless of what component changes i make mine seems very 2 dimensional, at a particular height and reflecting off whatever surface is between the speakers (no matter how far i bring them into the room).

Am wondering if room treatment might be the answer. Did you get any added height/width/depth from this tweak?

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How would you describe the changes (if any) to the soundstage itself? Regardless of what component changes i make mine seems very 2 dimensional, at a particular height and reflecting off whatever surface is between the speakers (no matter how far i bring them into the room).

Am wondering if room treatment might be the answer. Did you get any added height/width/depth from this tweak?

 

Believe it or not, vocals are now presented with a much stronger centre image, and other instruments stand out as being in their own space. In comparison, I found the pre-treatment sound to be a bit flat and homogenised. Front to back soundstage depth is also slightly improved.  I guess this makes sense, as the reflections off the walls must play havoc with imaging and sound staging. The speakers can finally work their magic without the walls interfering as much as they previously were.

 

Don't get me wrong... my setup is far from perfect... but I am still astonished at the improvement. It was the same kind of 'hello!!' revelation as when I upgraded from Usher S520 to Lenehan ML1 speakers a few years back. I guess this makes sense, as it is removing a form of distortion from the overall system (which includes the room).

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..excellent stuff Pete -- Now you're hearing that DAC properly. Enormous soundstage and pin sharp imaging..And the DETAIL...but not overly bright....

 

Starting to get a bit of the 2001's about it that room now...brilliant treatment -- the evolution continues...

 

post-113548-0-30075500-1402746244_thumb.

 

 

 

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It was the same kind of 'hello!!' revelation as when I upgraded from Usher S520 to Lenehan ML1 speakers a few years back.

Well that's hardly a small upgrade :-) I'm not surprised

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Well that's hardly a small upgrade :-) I'm not surprised

Indeed! That's just it... The sound has gone from 'so-so' to 'whoa!' :)

Be warned... I will be sprouting fanboi rubbish regarding room treatments for the next few weeks. I'm THAT impressed!

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I understand, It's truly something else when it all comes together. Apparently :)

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