Are Iso Boxes an acoustic nightmare?

Discussion in 'Recording/Live Sound' started by tonefreak, Aug 12, 2005.

  1. tonefreak

    tonefreak Member

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    I built my self an iso box that I put my 1x12 in for recording. Sennheiser MD 421 and e609 are the mics. Presonus Eureka and Joe Meek VC3 are my mic preamps.

    I've tried all the classic mic positions and ones no so traditional, but I can't seem to capture my amps tone.

    I just ordered a Royer 122 hoping that it will fix the problem.

    The iso box is lined with Auralex Sheetbloc and then Auralex 3" acoustic foam on top of that. The 1x12 sits inside on top of an Auralex Gramma Iso Platform.

    But could it be the acoustics in my iso box that's preventing the mics from capturing the tone?

    Help!!!!!
     
  2. t0neg0d

    t0neg0d Member

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    Haha... was trying to post to your original thread about the frustrated with Fuchs saying I don't like ISO boxes... when you changed the thread to ask about ISO boxes... so here is my response:

    IMO amp+iso box = bad thing. Though not much reflection is picked up close mic'ing a cab... I have noticed a BIG difference in recorded sound.

    Not really sure if this response helps much... but we have had fairly good success capturing an Fuchs OD 50. I can't say I am intimately familiar with the finer points of a Fuchs, seeing as they are not my thing... but the close mic'ing with a AKG C1000-S, using a CAD M179 for ambience at medium volumes seemed to do well. And 1' distance mic'ing with the NTK at low volume produced decent results as well.

    Will post a clip of the OD 50 mic tests soon.
     
  3. tonefreak

    tonefreak Member

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    I chose the Royer 122 because I don't have to worry about impedence matching and that it was designed with high SPLs in mind. I'm going to back it off the grill about 3" angled 45 degrees and then straight to see if there is a difference.

    I could be kidding myself, given that the ISO box is the kiss-of-death to room ambience... but I should get to something close?

    The reason why I mentioned the Fuchs is because that's the amp I noticed the difference. I also run a Germino Masonette, which I love, and it sounded alright. But now I'm wondering how much more I can get from the Germino if properly mic'd.

    I am just soooo bummed right now. Beautiful sounding amps, but because of my situation, I have to use the ISO box to keep volumes down.

    Is there any hope or am I kidding myself?
     
  4. TAVD

    TAVD Guitar Player Gold Supporting Member

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    Closed or open back 1x12 inside?
     
  5. t0neg0d

    t0neg0d Member

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    THD Hotplate and close mic'ing... there is a bit-o-funky response using one... but I have yet to hear it show up in a recorded line. Hope this helps.
     
  6. tonefreak

    tonefreak Member

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    Closed back.
     
  7. tonefreak

    tonefreak Member

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    If I understand... take the 1x12 out of the ISO box. Use the THD Hotplate to get the volume down. Close mic.

    Is that correct?

    BTW... I'll be up in Bellevue in a couple of weeks. I'm up there at least once a month to visit my son. Beautiful area!

    Thanks for the help!
     
  8. TAVD

    TAVD Guitar Player Gold Supporting Member

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    I'd leave the 1x12 in the iso box and still use the hot plate. Maybe some rockwool on the end opposite the speaker.
     
  9. t0neg0d

    t0neg0d Member

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    Yep yep on relaying that back... definately try it in and out of the iso box... even though atinuaters (no idea how to spell that) all do some funky-ish-ness thing to your sound, I like them much better than master volumes for sure... and the Hot Plate is by far my favorite thus far.

    You won't be unhappy with the purchase.
     
  10. tonefreak

    tonefreak Member

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    If I leave it in the ISO box, do I still need to use the Hotplate?

    I don't have volume issues when I use the ISO box. Maybe my problem is that the volume is too high in the ISO box and that's causing some acoustical problems?
     
  11. tonefreak

    tonefreak Member

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    Great suggestion... I've used a Hotplate before and while it's not the ultimate, the resulting tone sits well in the mix.

    I guess I've been running under the misconception that loud = good levels for capturing tone?
     
  12. Orren

    Orren Member

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    First of all, to answer your question, yes, Iso Boxes are acoustic nightmares. Nonetheless, when you have to use them (meaning you can't set up a great mic in a great room) I think they are probably the most "pure" option out there. But you have to figure out how to "mic the box" so to speak.

    The thing to remember about the iso box is that the sound coming directly out of your speaker is really the only "pure" sound that you want to capture. All those sound waves bouncing around inside the box are too trapped and muted to sound good. They double up on each other and reflect in weird ways. So the trick is to use mics that do a good job of rejecting all those other frequencies, and just capture what's coming straight out of the speaker.

    I don't know about the MD421 or your preamps, but one thing to keep in mind is that you do NOT want a mic/mic pre that emphasises lows, because that's what's bouncing around the box and causing the most problems.

    Well, the good news is that I have a Royer R121 and I think it sounds absolutely amazing--it captures a bright, lively, full range tone, absolutely spectacular on guitar. But the bad news is that like nearly all ribbon microphones, it has a figure 8 pattern. That means that it captures sound from the front and the back...fantastic for capturing great room sounds, but it also means, you'll be capturing all those boxy reflections.

    I actually wrote to Royer, and they gave me a great suggestion for sort of making a semi-circular reflecting disk and placing it 4" back from the royer, to keep it from recording from its backside.

    Basically, take a round plastic bowl, cut it in half, then take one half of that bowl and line the inside with 1/2" acoustic foam, so you have a half circle of foam. Hang that back from the Royer (or any figure 8 mic), and it should block off the back half of the figure 8. I've not had a chance to try it, but hopefully it will work!

    Certainly, the reflections inside the space are bouncing every which way. You might want to try cutting up an Auralex LENRD bass foam wedge and sticking it in the corners to catch some of the low end. But I think probably the best bet are to find really hypercardiod mic patters (or find tricks to block the rest of the pattern) and just capture what's coming out of the speaker.

    And make sure you have a great speaker, like a V30 or something! :)

    Orren
     
  13. Deaj

    Deaj Member

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    My situation is such that I rarely get to turn the amp up at home so I've been experimenting with low volume recording. The following two clips were recorded at volumes low enough to be played a couple of rooms away from my wife and boy in the middle of the night and never disturb them.

    This one is a Clay Jones overdrive into the clean channel of a Rivera Jake 1x12 combo using a combination of a HotPlate and the master volume to keep the volume down. The mic is a Rode NTK placed 12" from the speaker pointed at the center of the cone between the dust cap and the cone edge:
    CJOD+Jake+HotPlate+NTK

    This one is a Fuchs ODS 50 1x12 combo using only the master volume to keep the volume down. The mic is a Shure SM57 on the grillcloth center of the cone between the dust cap and the cone edge:
    Fuchs+MV+SM57

    Hope this is helpful :)
     
  14. tonefreak

    tonefreak Member

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    For all that responded... thank you sooo much!

    I bought a THD Hotplate last night and go the volume down in the box. Sure enough, all the bad refections in the ISO box were greatly reduced and the tone improve tremendously!!

    I'm a happy camper once again!!

    And I couldn't have done it without all your suggestions and advice!!
     
  15. alanfc

    alanfc Member

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    I found this in a serach, right up my alley-

    can someone opinionate on this for me:

    I have this 1x12 that I use for recording, its a Carvin v30-ish speaker in an open back cabinet. It's in a homemade iso-cab.

    In this situation, would I benefit by making the 1x12 cab closed back, in order to maximize the focus of the speaker and help me with crazy reflections bouncing all over in there?

    I usually close-mic with a dynamic but I always wonder if I could do better. I do have moving blankets on the walls/floor/lid of this iso-cab. But still I bet it gets crazy in there.
    thanks
     
  16. MichaelK

    MichaelK Member

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    Hey, you get major props just for saying "thank you." ;)

    I didn't respond so I take no credit, but glad it worked out. Enjoy.
     

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