Q. Can I use acoustic screens to effectively prevent drum spill?

Published in SOS November 2004
Bookmark and Share
I'm wanting to record a band all at the same time and in the same room, and my main problem is that the drummer is much too loud. I'll be recording them in a rehearsal room and I'm worried about the other performers' mics picking up excessive spill from the kit. Would it be possible or advisable to try and isolate the kit using some screens? I've seen live performances on TV where the drummer is boxed off with clear perspex screens. Would there be a suitable DIY alternative?

SOS Forum Post

Technical Editor Hugh Robjohns replies: It's virtually impossible to use free-standing screens to generate useful or effective sound isolation, but they can be helpful in reducing spill. They are most effective at high-mid and high frequencies — the laws of physics, the wavelengths of the sounds involved and the physical size of the individual screens determine which frequencies a screen will stop (or, at least, reduce) and which it won't.

qa D1 mic patterns.s
Using mic pickup patterns to reduce spill.
Using mic pickup patterns to reduce spill.

Don't expect screens to be able to help much in controlling low-frequency spill — the long wavelengths of low-frequency sounds mean that the spill will get everywhere no matter what! But you can screen off some of the mid- and high-frequency sounds, such as cymbal splashes and snare noise.

In my experience, rather than trying to box in the drum kit in an effort to stop its sound from escaping, screens work much more effectively if you place them around the microphones that are picking up the most spill, to try to keep the unwanted sound from reaching them. In terms of reducing the amount of drum spill recorded, stopping it leaving and preventing it from arriving come to pretty much the same thing, but the latter is far easier and more effective!

You can also reduce the amount of spill by paying careful attention to where you position the musicians relative to each other in the studio, the polar response patterns of their microphones, and where you point those mics. Cardioid and hypercardioid pickup patterns (see diagram), which reject sound coming from the rear and, to a lesser extent, from the sides, are the order of the day. Don't forget that, in addition to the direct sound from the kit, the other mics may also be picking up reflected sound from the surrounding walls. In such cases, an additional screen behind or to the sides of the performer and microphone can help to cut out those unwanted reflections.

Boxing in the drum kit with hard reflective surfaces (like perspex panels) often causes more problems than it solves. It is a necessary evil on sound stages sometimes, but as I say, I find you can get better results if you concentrate on trying to stop unwanted sound getting into specific mics from specific directions, rather than trying to stop the unwanted sound from leaving the source. That's more of a job for King Canute!

At the end of the day, you will probably have to live with a degree of spill, but this is not the end of the world, especially if you're aiming for a 'live' sound. In fact, in most cases a modest amount of spill only becomes a major problem if you want to overdub something like a completely different guitar solo, when you can still hear the original in the spill on other tracks! Barring any problems with phase cancellation (where spill from a more distant mic interferes with the close-miked signal — switching in phase reverse on the mixer channels for the distant mics should help solve the problem), spill can even help to knit the mix together in a subtle way.

As you are recording in a rehearsal room, in conditions which, I assume, will not be ideal, you will have to compromise — if you can get a dry enough drum sound, and can isolate each instrument enough to have control over the balance of the mix, consider your job done.

November 2014
On sale now at main newsagents and bookstores (or buy direct from the
SOS Web Shop)
SOS current Print Magazine: click here for FULL Contents list
Click image for November 2014
WIN Great Prizes in SOS Competitions!

 

Home | Search | News | Current Issue | Tablet Mag | Articles | Forum | Subscribe | Shop | Readers Ads

Advertise | Information | Privacy Policy | Support | Login Help

 

Email: Contact SOS

Telephone: +44 (0)1954 789888

Fax: +44 (0)1954 789895

Registered Office: Media House, Trafalgar Way, Bar Hill, Cambridge, CB23 8SQ, United Kingdom.

Sound On Sound Ltd is registered in England and Wales.

Company number: 3015516 VAT number: GB 638 5307 26

         

All contents copyright © SOS Publications Group and/or its licensors, 1985-2014. All rights reserved.
The contents of this article are subject to worldwide copyright protection and reproduction in whole or part, whether mechanical or electronic, is expressly forbidden without the prior written consent of the Publishers. Great care has been taken to ensure accuracy in the preparation of this article but neither Sound On Sound Limited nor the publishers can be held responsible for its contents. The views expressed are those of the contributors and not necessarily those of the publishers.

Web site designed & maintained by PB Associates | SOS | Relative Media