Homemade Vocal Reflection Filter

[france_54]

I know this has been dicussed a few times in different places but here is my homemade reflection filter. All made for less than £25 or $35. Works a treat.

[JoRillo]

Good job, i've seen another thread with basically the exact same build.

Question to any of the real smart caustic guys around here: Do you think the jagged foam would cause more comb filtering then a rounder/flatter piece of foam?

[SörenHjalmarsson]

Originally Posted by JoRillo

Good job, i've seen another thread with basically the exact same build.

Question to any of the real smart caustic guys around here: Do you think the jagged foam would cause more comb filtering then a rounder/flatter piece of foam?

The reactance of a given material will depend on it's impedance properties, it's hard to predict how the result of all the superpositioned waves would change with the shape, at the reciever. But no, the shape difference shouldn't cause any more noticeable "comb filtering" in a given absorbtive material. The benefit of sculpted foam is that it absorbs HF better at angle of incidence than a flat surface dito. In any case, one should never place the reciever and/or the stimulus so close to an absorbtive component that such small differences (between different shapes and/or materials) are percievable.



--Sören

[DanDan]

Soren, I think such Reflection Filters have to be close to work. That is, if they do work....

Nice one france.

Jorillo, I would guess that Pyramid foam would be even better, for the reasons Soren explained, i.e. better absorption due to the angle the waves hit the foam at.

DD

[Drywsef]

Very nice, France. May I ask where you got the metal trifold? I am tempted to try something similar with pyramid foam.

[SörenHjalmarsson]

Originally Posted by DanDan

Soren, I think such Reflection Filters have to be close to work. That is, if they do work....

Bulls eye!

The effectiveness of a small reflection filter is questionable and the fact that it needs to be placed in close proximity to the source and reciever, in order to "work", it also makes the recording vunurable to near-field side-effects such as reactance i.e. undesirable coloration!



-Sören

[DanDan]

Indeed Soren. I strongly suspect the larger devices that work a bit further away should be much better. However friends of mine are using the SE, ( a great company) and are very happy with the result. So it is hardly fair of us to spread doubts based on theory, without tests to show up the effects you speak of. As I say SE seem to be a very good company.

DD

[SörenHjalmarsson]

Originally Posted by DanDan

Indeed Soren. I strongly suspect the larger devices that work a bit further away should be much better. However friends of mine are using the SE, ( a great company) and are very happy with the result. So it is hardly fair of us to spread doubts based on theory, without tests to show up the effects you speak of. As I say SE seem to be a very good company.

DD

Yes, with larger devices that can be placed out of the near-field (where possible reflections will have been properly attenuated, due to distance, before reaching the reciever) it's easier to prevent that this effect is aloud.

When it comes to tests i belive that Mr Brandt is still waiting for those... JH Brandt - Recording Studio Design & Acoustics - VooDoo Sites

Seriously... I'm sure that the SE (and simular) can work well for some people in certain situations, i'm merely trying to raise an awareness to the possible close proximity side-effect that can occur with any kind of device (big or small) if positioned too close.

A practical, "out of text book", exibition of that can be found here: http://www.gearslutz.com/board/6395612-post34.html


-Sören

[DanDan]

Perhaps when it is very very close the effect becomes beneficial.
I took a listen to your linked example.
Trust me I am not being difficult here, I prefer the one close to the 703!

Recording sounds is all about colouring. An acoustic guitar played 'at' a hard wall will give great feedback to the performer, making it an enjoyable experience. The slapback and comb filtering will be horrible technically, but that very combing can make it nice and twangy.

Singers sing at CR or booth windows all the time. I strongly expect a Reflection filter may be a better compromise than the bounce from that glass.

I think there is a whole large thread here somewhere on the SE, I may take a look

DD

[SörenHjalmarsson]

The effect caused by the absorbtive panel in this example sounds much like that what you can get sometimes in an untreated room viz. the low mid mud "room effect". This usually result in so called "vocals behind the curtain", which makes the vocals a bit muffled and too unintelligible in an arrangement. Solution: cut some low mid with an EQ and/or boost a bit in the speech and "air" regions. Better Solution: Treatment and/or placement! (you can't really EQ away comb filtering)

Personally, i dont consider this "low mid mud" a positive coloration (such as the 3D effect, slap back or harmonics one can get from other reflections) and i would probably try to move the mic closer to the source if i wanted some "proximity effect", but recording is a subjective art... And when it comes to that art one shouldn't, of course, throw your opinion out the window lightly DD....

[DanDan]

Are we listening to the same files?
To my ear, known to be 24 carat, ;-) the one with the filter/703 has less warmth i.e. low mid, and has a sort of presence or slight raspiness. Typical comb filter tonality.
The second wav is definitely cleaner, has more bottom and a HF open-ness.
Which will cut through the mix better or sound more musical is a taste thing.
The SE thing has a bit more than just foam or fibre going on. It may well deliver a better sound than facing glass or an untreated room.
Tests definitely trump assumptions, and if not available, the ear/brain is surely the arbiter?

DD

[SörenHjalmarsson]

Originally Posted by DanDan

Are we listening to the same files?

I will have to take a listen tomorrow DD (haven't got acces to speakers at the mo). I haven't listened to those files since ~Mars, but i do seem to remember that the evident difference was at a boost at a certain frequency in the low mid, which doesn't *sound* so good in theory...



*Pun intended*

[DanDan]

A crazy guy over here hears the same low mid thing when he shouts at 703
;-)
Owens Corning 705 and 707 and is king!

I couldn't hear a difference on my iMac speakers so I plugged in cans.
The one near the 703 does sound a bit more present, but is definitely coloured. There is no room tone on either so the possible benefit is not possible. i.e. getting a dry sounding vocal in an open room.
I prefer the unaffected on today!

france I hope you do tests with and without it. Let's not simply assume it is either beneficial or not, Soren's reasoning is valid.

DD

[SörenHjalmarsson]

Originally Posted by DanDan

A crazy guy over here hears the same low mid thing when he shouts at 703
;-)
Owens Corning 705 and 707 and is king!

Well... He hears alot of things....

I couldn't hear a difference on my iMac speakers so I plugged in cans.

My home computer speakers have the same limitation, that's why i didn't bother to listen...

I prefer the unaffected on today!

I totally agree on that! The version without the RF sounds tighter and cleaner across the spectrum...

I took a listen in the studio today and i am experiencing the exact same thing as last time (http://www.gearslutz.com/board/6428684-post6.html). There defenetively is a low mid boost (at ~133Hz) that makes the recording with the RF a bit more muddy. Besides this specific fc boost (which is relatively easy to deal with) there also is a thin and phasey, more classic combfiltered sound going on somewhere else... not very nice IMO! I.e. there defenetively is some constructive and destructive interference caused by the RF!!!!!!

To demonstrate this a bit clearer (for those of you who may not have the golden ears of Sören and DD ) i have attached the two files in this post. Both of them have recieved the exact same treatment viz. an 11db boost at 133Hz with a narrow Q. NOW one can clearly hear how differently the two tracks react to that same treatment. The one without the RF doesn't change that much, whereas the other one gets more mud BIG TIME!!

You can all try this at home by using the original files if you'd like. Place them on separate tracks, apply an eq on the stero out and boost it ~10db @133Hz with a narrow Q value. Now you can switch between the tracks and hear how differently they are affected. The original files can be found here: http://www.gearslutz.com/board/6395612-post34.html

france I hope you do tests with and without it. Let's not simply assume it is either beneficial or not, Soren's reasoning is valid.

Exactly my point!

Test it and see what's best for you, if you like it you like it! What i'm trying to do here is to create an awarness of a possible side-effect and to provoke some critical listening while placing something, such as a reflection filter, in close proximity to the source/reciever.

Does your RF REALLY help? Does it remove the "room"? Is there anything else going on, something that might affect the recording negatively?

Pay extra attention to the low midrange and look for thin, undesirable and general 'phaseyness'.


/Sören

[SörenHjalmarsson]

Like you said DD, there is no evident difference/improvement between the files wrt Room sound being removed, however there is an evident difference...

[DanDan]

There is a vast thread here on the SE filter. SE reflexion filter ... anyone used this ?
I took a listen to a couple of the clips there. Although some did obviously remove some room tone, I didn't like them either.

DD