Moving Boxes


So there were some questions on Twitter when I posted that we were removing a couple of our guitar amplifier isolation boxes so a short post seemed like the best way to elaborate on what’s going on.

First off, we’re not eliminating guitar amps. I love amps, and I’m still not a big fan of the popular alternatives; I can make them work, but they’re still not the same within the context of a mix, although I’m not sure that’s entirely a sound quality issue….maybe another post someday on that…

This week we retired two of our original isolation boxes because we’re building new ones. The existing boxes were version 1.0 and still work great. They are a great size for most combo amps and some speaker cabinets, however,as you can see from the photo here, space is tight with bigger cabinets; internal dimensions are probably close to 4′ wide by 4′ deep x 2 – 2 1/2′ high. The originals will most likely be finding a new home within our organization, but if they don’t we’ll probably be looking to sell them.


We’ve wanted bigger boxes for some time, and due to some projects that are happening it seemed like a good time to start replacing them. The new boxes will be near carbon-copies of the ones designed by my friend Chris Briley at our Browns Bridge and Buckhead campuses. They’re essentially 4′ cubes and will most likely be treated on the inside with 2″ of rigid fiberglass wrapped in acoustically transparent fabric. I have a post from a few years ago with a little bit more info on what goes in version 2.0, but I don’t have any hard plans outside of those since these are pretty simple in design.

As the new boxes come together, I will try and post photos via Twitter and maybe here once everything is done. I will also be happy to put anyone in touch with the guy I have building ours if you’d like to get some boxes made for yourself but would like to skip the DIY route.

If you have any more questions, please leave them in the comments.

David Stagl

11 Responses to “Moving Boxes

  • Lionel Miller
    13 years ago

    Hi Dave,

    Thinking about picking up a Radial SGI which I notice you are using in your ISO cabs. Just wondering what you / your guitar players do with the ‘Drag’ control?



    • I don’t think they really touch the drag control. It’s probably set in the middle most of the time.

      • Lionel Miller
        13 years ago

        Thanks, I guess then they have no complaints of the unit changing the sound then?

        • It probably does change it a little, but I can’t remember any complaints. When we switched to the SGI’s, we were coming off a different method that had a much larger impact on sound so the SGI’s were a revelation at the time.

    • Lionel,

      This is probably too detailed for the comments section of a blog post, but let me explain a the purpose of something like the drag control:

      The pickups in your guitar are small wound wire coils, and they have some inductance. Also the pickups, volume control, and cable on the guitar combine to form a resistance and tiny bit of capacitance.

      Finally, the input stage of your tube amplifier has resistance and a capacitance known as the “Miller capacitance”

      These things combine together to create an LCR resonant filter that effects (by boosting) the top end of the frequency response of the signal that is feeding the amp’s tube input stage.

      A control like drag is to shape the value of the direct box’s input impedance so that it mimics the amp’s input impedance, and therefore this LCR behavior.

      • Lionel,

        I looked in the SGI manual after composing the above, and the Drag control does indeed provide a “resistive-capacitive” load to your guitar pickups, as I hypothesized above.

  • In this much older post: http://www.goingto11.com/?p=224 you talked about how some of your guitarists were starting to use Line6 PODs to emulate the guitar amp sound. Have most of them “come back home” to using real amps?

    • Some have gone back to amps. Some are using the newer “HD” PODs. Some guys do a hybrid of a POD into an amp. It’s a pretty fair mix right now.

  • Hey Dave, have you ever tried using a speaker a speaker emulator/load box like the Palmer ADIG-LB, if so what are your thoughts on it? I have toured with a few bands who use them live (We The Kings, The Cab) who get some great tone, and it makes dragging around equipment that much easier. The church I am the current TD at is running all POD XT Live’s straight into the house. It’s brittle, lifeless, and well since most of the guitarist don’t know how to get a good tone out of it, it’s a pain to mix without going and rebuilding all their patches. The budget doesn’t really support the build of iso boxes and purchasing of new mics and amps.

    • I haven’t used them, but I’ve been interested in trying one ever since I found out Alex Lifeson was using them with Rush on tour. Not sure if it would solve your issue because I’m guessing you still need good tone on the way in to those things.

      I think part of the problem with POD’s is that a lot of guys dial in their sounds using headphones or in-ears. Try getting them to dial in their sounds through the PA. Plug them in right at FOH and have them go to work.

  • Lionel Miller
    13 years ago

    Phil, Thanks for the information. I had one in on demo for a Sunday and it worked great. So have now purchased two, to cover all our current line ups. An initial play with the Drag control didn’t seem to radically change the sound. Which is fine by me we will leave it alone by default.

    Previously we were just using Balanced Jack – XLR adapters and with some Amp/Pedals experiencing signal loss and hums etc. This is a much more professional and reliable solution.