Will having a screen between your speakers affect comb filtering?

I was recently asked by Christopher who runs an excellent Google + group for recording engineers “Will having a screen between your speakers affect comb filtering?”

Dennis: Okay, so Christopher’s on the right track. His thinking about surface area but it’s not the thickness of the monitor that’s the issue. It’s the surface area that the reflections strike. Big surface area, reflections strike it. So the thickness of the monitor doesn’t matter. You could have a piece of cardboard up there and if it had a large surface area, then that’s a surface area that middle and high frequencies can bounce off of. So that monitor has got to be made larger. Here we go, consumerism can prevail here. Let’s get a larger monitor and move it to the front wall so that that distance between the speakers and the listening position, that’s our sacred ground, that’s our sound triangle and nothing in the way of that.

What do we have to live with?

We have to live with our console because that’s how we make our living but it produces comb filters too. So how do we eliminate that? We can’t. It’s just a necessary evil. But we can elevate our speakers and then tilt them so that the first angle of attack of the energy hits our ears first and not the console. What is the angle? What is the height? I don’t know, it varies for each different situation. Depends on the width of the console, depends on the length of the console, depends on the volume and dimensions of the room. All variables are inter-related. You can’t move one without impacting the other. So no computer screens between the monitors.

AD: Alright, moving on. Someone else has asked why do you spend a lot of money on topnotch speaker and amps but inside the cabinet its very cheap wires. What effect does this have on sound and what are benefits of changing the wires in the speakers?

Dennis: Well this is, I have to laugh because I’ve been in this business a long time. I’ve been into hi-fi since I was 16 so I don’t know how long ago was that 45, yeah 45 years ago something like that. So this was a debate years and years and years ago. Now here’s what you have to remember, in theory, yes, you should use a very high quality wire inside the speaker. In practice, you have to remember that that final sound that comes out of the speaker is a combination of about ten variables: the quality of drivers, the size of the drivers, the electronical components in the crossovers, the cabinet size, the internal cabinet fill material, the density and composition and materials used in the cabinet construction.

So remember though that a palette that a painter uses, he sticks his hands through a palette, he’s got all these paint colors and it gets this paint, this paint, and this other paint. Well that’s what the speaker is. It’s a palette of many, many things. So the designer, to produce the final sound, the cable probably accounts for maybe 5% or 2% or 1% of the final sound.

So in the big picture it’s not that big of a deal and here’s another reason behind that, the lengths that they use inside those speakers are very short. The distance between the crossover, if you tear your speaker apart, and I’m not telling you to do this but if you go inside your speaker, you will see that the crossover in the driver’s speaker are really close to each other most of the time. So the length of the cable is very short. When you have really short distances the quality level is not that critical. When you have long distances you need thicker cables because you have signal loss and all kinds of other issues interference RF from the air and our cell phones and all that stuff.

So the lengths are short but most speaker manufacturers today do use good quality cables. So I think it’s something that they do and I know speaker manufacturers personally, they actually design speaker cables for particular manufacturers to meet the manufacturer specifications. So it’s a great question. It was a question that’s been discussed for years and years and years but you’ve got to remember that the final sound that comes out of the speaker is a composition of many, many variables of which this thicker quality issue probably not that important in the total picture because the lengths and the amount of cable that are used is so small.

In Summary

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Thanks
Dennis Foley