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AV Rant #265: First!

January 5th, 2012

Today’s the first podcast of the new year, Tom is still on vacation and Rob is here filling in. We’re talking about some sad news to start off the new year.  Kodak might be filing for bankruptcyBerkline went out of business in May, and Gibson and Onkyo announced a new business deal. Rob’s soup to nuts this week is on Calibration, both for video and audio: see links below the cut. Liz found a USB adapter for vintage video games, Retrode, which you should all check out. (And send us your old game cartridges if you don’t want em!) Liz and Rob go way off topic about TV content via the internet and cable television providers. Thanks for listening and don’t forget to vote for us at Podcast Alley! To see our (mostly) complete collection of show videos, click here. Download Tom’s FREE ebook Bob Moore: No Hero which is pretty much available everywhere. You can also check out Tom’s new book, Bob Moore: Desperate Times on Amazon (and pretty much everywhere else, links coming soon!). Friend Tom and Liz on Google+ to join in on one of our hangouts.


 Video Calibration:

CalMAN from SpectraCal: http://store.spectracal.com/
Audio Calibration:
A great Sound & Vision Magazine article on DIY measurements: http://www.soundandvisionmag.com/article/how-diy-audio-measurement
Another Sound & Vision Magazine about the famous Radio Shack SPL Meter, a better SPL meter (for more money) and why neither are really ideal for audio calibration: http://www.soundandvisionmag.com/article/check-mate-spl-meter-good-measure
Studio Six Digital – makes products that turn your iDevice into a full audio calibration suite!: http://www.studiosixdigital.com/
Audio Tool for Android – a pretty amazing $6.50 app for Android phones: http://www.appbrain.com/app/audiotool/com.julian.apps.AudioTool
TrueRTA – professional level measurement software: http://www.trueaudio.com/rta_abt1.htm
Room EQ Wizard (REW) – the FREE, utterly amazing software from Hometheatershack: http://www.hometheatershack.com/roomeq/
Dayton EMM-6 microphone – the inexpensive mic that every DIY’er should have: http://www.parts-express.com/pe/showdetl.cfm?Partnumber=390-801
ART USB Dual Pre – the pre-amp you need to power and connect the Dayton EMM-6 mic to your computer: http://www.parts-express.com/pe/showdetl.cfm?Partnumber=245-8688
Behringer Feedback Destroyer Pro – the EQ/filter box that lets your measurements actually do something to fix the sound in your room!: http://www.parts-express.com/pe/showdetl.cfm?Partnumber=248-657
RealTraps Test Tone CD – a FREE bass test tone CD for manual measurements: http://www.realtraps.com/test-cd.htm
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  1. January 5th, 2012 at 16:19 | #1


    • January 11th, 2012 at 23:14 | #2

      This podcast should be showing up in iTunes soon.

  2. jnmfox
    January 13th, 2012 at 13:26 | #3

    Thanks for the link and info on the audio calibration. I have looked into using REW and even purchased some of the cables but jus never got around to it. I’ve also thought about getting a SMS to easily calibrate my sub but the price has always put me off.

    We cut the cord several years ago and about the only thing I miss is ESPN (We also got into Breaking Bad so the last 2 seasons I purchased on Amazon so we could see it the week it aired). I set-up a PC based DVR (SageTV) and with just locals we feel like Liz in that we watch too much TV. Add in Netflix and there is almost always something to watch.

  3. Rob H.
    January 13th, 2012 at 14:19 | #4

    I’m so happy you liked the calibration info, jnmfox! I always talk too much when I’m on, but there’s just so much good stuff out there! I can’t help but want to talk about it all :p

    Systems like the Velodyne SMS or SVSound Audyssey AS-EQ1 are pretty much the same idea as using REW and a Behringer Feedback Destroyer – or other supported EQ unit – to measure the response, cook up some correction curves, and automatically set those curves in a parametric EQ. The thing is, with SMS or AS-EQ1, you’re relying entirely on the mic that they supply and it’s a mostly automated system.

    If you actually want too see what the frequency response looks like at your seat, you wind up needing your own measurement gear anyway! Personally, I think anyone who’s into home theater and audio really ought to have at least a good SPL meter and REW so that they can at least get a “ballpark” look at their frequency response in their room. A good mic like the EMM-6 plus the necessary USB pre-amp aren’t terribly expensive though, and quite a bit more accurate in the all-important bass region, so that’s really what everyone should have, IMO 🙂

    The EQ is where you have more options. The Behringer FD is an easy example because it’s not too expensive and REW can program it automatically! But there are certainly others. Plus you could still use one of the automated systems. Having your own mic and pre-amp just lets you really see what that automated system did, and perhaps make some manual adjustments of your own 😉

  4. Ralph
    January 24th, 2012 at 11:50 | #5

    Hi Rob, just finished listening to your soup-to-nuts on calibration and I have a question about how you would integrate the Behringer FD into a 5.1/7.2 HT setup? It seems that this product will work only for a 2-channel setup.

  5. Rob H.
    January 24th, 2012 at 13:29 | #6

    Hi, Ralph.

    A unit like the Behringer DSP1124P Feedback Destroyer Pro is indeed, only a 2-channel unit. Most of the time though, you’d only be looking to EQ your subwoofer(s). Higher frequencies are a lot less affected by the room, so it’s mostly the bass that you want to EQ and NEED to EQ. You speakers are better served by simply placing them carefully and maybe introducing some absorption and diffusion panels to break up any strong wall, floor or ceiling reflections. It’s certainly possible to EQ your speakers as well, but this changes the “character” of your speakers. If what you are after is ruler-flat frequency response, then EQ can help your speakers as well. But it’s really the bass that we’re mostly worried about because the room plays such a huge role in how the bass response appears at your seat(s) and there are almost always severe problems in the bass response, much less so at the higher frequencies.

    An EQ unit like the Behringer sits in between your A/V processor (receiver or pre/pro) and the amplifier for the speakers or subwoofers. For subwoofers, this is easy because most subs have their own amp built in. So you simply connect the A/V Processor’s “Sub out” to the EQ unit, and then connect the EQ unit to the subwoofer’s input.

    If you want to EQ your speakers, you have to use separate amps. You’d run the pre-out connections from your A/V processor to the EQ units and then connect the EQ units to the separate amps for your speakers. You’d need as many EQ units as you have PAIRS of speakers. But again, normally, we’re only worried about EQ’ing the subwoofers 😉

  6. Ralph
    January 24th, 2012 at 14:17 | #7

    Rob, thanks for the quick and detailed reply. After I posted my question I did some more research and that’s exactly what I found (i.e. EQ subs).

    So my follow-up question would be if you have a AVR that has a EQ system like Audyssey or some other built in EQ software, is it better to use that to calibrate your system vs the solution you discuss in the podcast (mic & software) or are the two doing different things? I understand that having your own EQ hardware/software allows you more flexibility in calibrating a system when something like Audyssey is not available (older receivers come to mind) but besides that case, if you do have software EQ on your AVR is it a better option?

    Thanks in advance.

  7. Rob H.
    January 25th, 2012 at 15:36 | #8

    It depends on what “level” of Audyssey you have and you still need to be able to measure, IMO.

    Audyssey can only do so much. Like any EQ system, it cannot “fill in” big dips that are caused by cancellations. So you still need to combat any big dips first by simply placing your subwoofer(s) carefully in relation to your seat(s). Confirming that you have no big dips still requires measurement, so you at least want to have an SPL meter and REW to give yourself at least a rough idea that you don’t have any huge dips at your seat.

    If you have MultEQ XT32, you should be in pretty good shape EQ wise after that. The XT32 version is pretty comprehensive and is capable of a lot of correction in the bass. But you’d still want to measure afterwards to confirm 😉

    MultEQ XT does apply EQ to the bass, but it isn’t as precise or granular. It’s around 1/6th octave smoothed, so it can potentially “miss” some peaks if they are narrow.

    Regular MultEQ or 2EQ don’t really do much for the bass, so you’d want a separate EQ solution for the subwoofers for sure with those.

    MultEQ XT and MultEQ XT32 are a good deal. They are certainly worth a try before you go and buy a separate EQ unit! I would definitely want to measure and confirm the results though – I wouldn’t just blindly trust Audyssey to do it all automatically 😉

  8. Ralph
    January 25th, 2012 at 17:22 | #9

    Hi Rob, thanks for the extra info. My AVR has EQXT but now I’m going to need to convince the wife “why” I need to spend some more money to get some additional hardware 😉

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