Controlling desk reflections

[Aled Hughes]

It just occurred to me that I could put some mineral wool or foam under a couple of these kind of things on the desk in front of my speakers (small home setup with speakers on the desk at the moment), and have absorbers that also doubles as a stable desk surface on occasion. Any opinions?!

https://www.etsy.com/uk/listing/1039849 ... 1039849955

[Hugh Robjohns]

You'd have to cover mineral wool with a fabric bag to prevent loose fibres breaking free, and foam could get dusty.

I'm not sure if just covering the area immediately in front of the speakers would be sufficient. Past experiments using towels and duvets suggest to me that the whole table surface is significant in audible reflections.

Martin Walker of this parish found that raising the rear of the desk by a few inches (to angle the desk surface by about 6 degrees) made a big difference without things falling off!

[Drew Stephenson]

Martin Walker of this parish found that raising the rear of the desk by a few inches (to angle the desk surface by about 6 degrees) made a big difference without things falling off!

I still don't see how this is any different to angling the speakers back 6 degrees.

[Hugh Robjohns]

I still don't see how this is any different to angling the speakers back 6 degrees.

Angling the desk moves reflections from your ears to your chest and thus reduces the audible colouration.

Angling the speakers means the tweeters are no longer pointing at your ears and may alter the tonal balance unhelpfully.

Reducing the height of the speakers, to make the reflections more oblique AND tilting the speakers back to keep the tweeters on axis may serve as a practical alternative.

[Aled Hughes]

You'd have to cover mineral wool with a fabric bag to prevent loose fibres breaking free, and foam could get dusty.

I'm not sure if just covering the area immediately in front of the speakers would be sufficient. Past experiments using towels and duvets suggest to me that the whole table surface is significant in audible reflections.

Martin Walker of this parish found that raising the rear of the desk by a few inches (to angle the desk surface by about 6 degrees) made a big difference without things falling off!

Thanks,

Yes maybe the whole surface is the issue - I've just taken delivery of a new ceiling cloud and bass trap today, and I laid the ceiling cloud flat on the desk, covering the whole of ti, and it made quite a difference, which is what got me thinking. I've ordered the smallest cheap panels that Studiospares have to see how if just placing them in front of the speakers help. I reall need to raise the speakers too. At the moment they're standing right on the desk on 3 IsoPucks each.

It's a small room and a small desk, and the speakers (and my head) are close together. When I get the bigger room done placement will hopefully be a bit easier!

I read Martin's thread about angling the desk too, so that's worth considering. Or perhaps I could angle the speakers upwards seeing as they're below ear level at the moment. A bit tricky with the IsoPucks though...

[Drew Stephenson]

Reducing the height of the speakers, to make the reflections more oblique AND tilting the speakers back to keep the tweeters on axis may serve as a practical alternative.

Sorry, that was my point really, it's the angle between the line of the speaker projection and the desk that's important isn't it?

[James Perrett]

I found that raising the speakers quite a way (40cm) from the desk helped. The tweeters are now higher than ear height but the response seems smoother (though I haven't done any measurements).

[Martin Walker]

I found that raising the speakers quite a way (40cm) from the desk helped. The tweeters are now higher than ear height but the response seems smoother (though I haven't done any measurements).

In my previous small studio an acoustician recommended raising my loudspeakers above my desk on 15-inch stands (ironically about the same as your 40cm movement) and then angling then slightly down to point at my ears again to get a smoother response.

However, this was because I didn't have enough room to fit much acoustic treatment, and the upward shift of the speakers placed them into a smoother position in relation to the room modes.

In my current studio I'm still frankly amazed at the improvement my 6 degree desk angle has made, and all it needed for a quick tryout was to slide some 3-inch thick wooden blocks (two six-inch sections from an old fence post) under its back legs. Well worth a try!

Martin

[Philbo King]

This is an interesting topic. I recently added a 4 foot x 2 foot x 2 inch absorber panel flat on my desk riser between my speakers. An immediate change in sound was noted.

Yesterday I ran REW with a measurement mic, using its EQ function to create a stereo EQ impulse file for the listening position. The peaks and valleys for the upper bass and mid-range raw (unEQed) measurements were notably flatter than prior tests without the panel. So desk reflections really do have a large effect.

I haven't yet tested the system response with EQ in place, but will post results when I do.

[ef37a]

It's 'the other way around' but I believe BBC announcers desks were made with a metal grill covered with a thin foam to eliminate desk reflections?

Dave.

[Hugh Robjohns]

Yes, perforated metal grating with foam/felt on top and a tough acoustic fabric as the top layer.

Canford still make them in various formats.

https://www.canford.co.uk/CANFORD-STUDI ... TIC-TABLES

[ef37a]

Yes, perforated metal grating with foam/felt on top and a tough acoustic fabric as the top layer.

Canford still make them in various formats.

https://www.canford.co.uk/CANFORD-STUDI ... TIC-TABLES

Well! Blows me down! I thought such things had been relegated to broadcasting history!

Dave.

[jaminem]

Eric valentine, does a similar thing with his studio desk. They used the same metal that’s on the top of the old akg mics and that Aston pencil mic, I want to say it’s ‘sintered’ but that maybe the wrong word, but if you check out the barefoot studio tour on YouTube you can see it