[Mike-48]

I recently figured out that the two small windows in my room are causing irritating reflections. Temporarily putting up a couple of small towels made a surprising improvement.

For a permanent solution, I'm hoping that cellular (honeycomb) shades will provide sufficient NRC and also break up reflections. Double-cell blinds seem like they'd be best. This may not be a perfect solution, but it's the only one I've thought of that will let light in while doing its job.

The shades will be hung with about 6" of space between them and the panes, to allow the hopper windows to open and let in air.

I'd appreciate comments from those who have used cellular shades for acoustics.

[aldcoll]

I can't share any acoustic impressions but as a Oregon experience ours molded rather quickly.  The reason being they  fit the window tightly and were closed most of the time thus no air circulation.

We have had to modify what and how we use shades.  They were on a moderate efficiency window.

There are some that they sale with a poly side and fabric side for visual.  Just have to open and have installed away from flush to window.

Alan

[Mike-48]

Alan, Thanks for sharing your experience. We have quite a few cellular shades already but fortunately, haven't had any mold problems. Perhaps that's because they are all in heated and air conditioned space and are opened and closed frequently. A bummer that you had that happen.
Happy listening!

[mresseguie]

Hello, Mike.

We have cellular shades throughout our home. I often leave them down when I listen to music (as long as my wife doesn't mind). I've never deliberately made an A/B comparison, but I believe I notice an improvement. My room has few acoustic treatments - as Alan can attest to.

Michael

[JLM]

As always go to the acoustical measurements, but doubt if they'd be more than nominally effective.  As far as absorption goes there's almost no material to absorb any sound, but would be better than bare glass.  As far as diffusion goes they're not solid enough to deflect sound and could only be effective at one frequency (around 15,000 Hz based on the depth of the pleats).

[cementhead]

I installed the double cell on my windows, as I have ALOT of glass in the listening/living room. It is better than reflecting off the windows, and definitely helps with the heating and cooling!

[Mike-48]

Thanks, all, for the comments! It sounds like the cellular shades, though not perfect as acoustic treatments, will help break up the reflections a little. So far, I haven't found a better solution in this specific case.

[Tyson]

I use a combo approach for my windows.  I use wood slats on the interior of my windows (diffusion) and then heavy linen roman shades over the top of the window frame (absorption).  I find that both together work better than either alone.  And better than the cellular shades. 

[youngho]

Hi, here are some numbers, for what they're worth: https://wcp.hunterdouglas.asia/br/br_Duette.pdf

[Mike-48]

Hi, here are some numbers, for what they're worth: https://wcp.hunterdouglas.asia/br/br_Duette.pdf

Thanks! It's encouraging that the NRC is pretty high in the kHz range. That should be enough to take care of the annoying first reflections from these small windows.

@youngho - Do I remember you, perhaps, from the old TacT Users' Group?

[youngho]

Mike, I couldn't find any data on double versus triple cell blinds, but my assumption would be that more layers would give more higher frequency absorption, possibly at the cost of smaller airspaces within the blinds themselves affecting lower frequency absorption, but you should be able to improve that by spacing the blinds away from the windows so that there's an air gap.

One other option to consider (not mutually exclusive with the blinds) is the Clearsorber product from RPG:
https://www.rpgacoustic.com/documents/2018/01/clearsorber-panel_data-sheet.pdf/
https://www.rpgacoustic.com/documents/2017/06/clearsorber-foil_data-sheet.pdf/

You'd have to remove the Clearsorber panels for ventilation, though perhaps you could combine with compression tubing along the edges, like the Indow inserts: https://indowwindows.com/

I had purchased some grey Vicoustic Multifuser DC2s after contacting you about a system picture from your gallery.

[rbbert]

I use a combo approach for my windows.  I use wood slats on the interior of my windows (diffusion) and then heavy linen roman shades over the top of the window frame (absorption).  I find that both together work better than either alone.  And better than the cellular shades.

How much if any light comes through?

[Tyson]

How much if any light comes through?

Very little light gets through.  That's by design, as I do most of my critical listening in the evening and just do background listening during the day.

[Mike-48]

One other option to consider (not mutually exclusive with the blinds) is the Clearsorber product from RPG:
...
I had purchased some grey Vicoustic Multifuser DC2s after contacting you about a system picture from your gallery.

Thank you for suggesting the Clearsorbers! I have angled plastic panels in the windows now, and I might be able to replace them with Clearsorber panels and solve the problem without adding blinds at all. I'll definitely look into that.

I hope the DC2s are working out for you.

@Tyson - Thanks for your ideas. I am going to keep it simple, as the windows are small and not a huge part of the acoustics of the room. Your system sounds much better acoustically for large windows than simple blinds would be.

[Tyson]

In a common room the Clearsorbers or the cellular shades might be a better option, you're right.

[youngho]

Mike, I forgot to mention that there is also Realacoustix: https://www.realacoustixllc.com/deamp

[Mike-48]

Thanks, @youngho. I've written RPG to ask a few questions, the main one being if there is scattering at higher frequencies, rather than ordinary reflection. If so, these panels look ideal for the situation.

[Mike-48]

To close off the topic, the RPG Clearsorbers have a minimum run of US$13,000 + $2,000 shipping, which puts them out of my budget for this project . . . to say the least!

HOWEVER, I realized that I can re-orient the plastic panels over the windows so that they will reflect sound above the listener's head, instead of at it. I did that with materials at hand, and it seems to have solved the problem. So no need to add shades or more acoustic treatment . . . a lovely solution!

This is the only non-symmetrical part of the room, and the only one not amenable to usual acoustic treatments. That threw my thinking off for a long time. I am keeping fingers crossed that I have solved this for good -- and BTW, it seems I now have smoother sound than I've had in the room before.

My sincere thanks to all who offered ideas about this issue. It took much thinking and experimenting with the situation to figure out the best approach, and your ideas were very helpful in stimulating thought.

Mike

[youngho]

Thanks for the follow-up. That's good to know about the Clearsorbers.