Logidy EPSi Review:
The First Customizable Convolution Reverb Pedal

One of the coolest gizmos from last weeks NAMM show is already in my grubby little hands: It’s the Logidy EPSi, the first customizable convolution reverb pedal. I ordered it the instant I heard about it, and it arrived right before I left for Anaheim.

Convolution (or impulse response) reverbs can mimic acoustic spaces and outboard gear with astonishing accuracy. (If this concept is new to you, check out this article by me. Or better yet, this one written by someone who knows what he’s talking about.) Nutshell: You create impulse response (IR) files by playing and recording a test tone in rooms or through gear. Once you load the file into an IR reverb device or plug-in, it can make anything sound as if it was recorded with the same ambience.You can also generate eerie, otherworldly sounds by loading unusual audio files.

Many software and hardware amp and effect modellers use IRs to mimic gear. Software convolution reverb plug-ins such as Audio Ease’s Altiverb, Logic Pro’s Space Designer, and Waves IR1 include reverb libraries, and also let you load your own IRs. But as far as I know, EPSi us the first device that lets you load your IRs into a stompbox and access them without playing through a computer.

I’m psyched to add IR reverbs to my (mostly) analog pedalboard, and EPSi makes it relatively easy to load the IR libraries I’ve compiled. The files require special treatment: They must be 44.1kHz WAVs, and the names must be formatted quite specifically, as detailed in Logidy’s documentation. The interface is extremely minimal: just a bypass footswitch and a knob/button pair to navigate the simple menus.

This unique reverb stompbox sounds great and offers limitless opportunities for creative sound design. You can load your own impulses, or add ones from from some of the fine freeware libraries online. (Thanks for the link, Scott!) On the downside, it’s difficult to load or edit sounds on the fly, so while it might be fun to spelunk for new sounds in the studio with EPSi, don’t plan on modifying sounds onstage. (The ability to recall several saved presets would vastly improve EPSi as a gigging tool.)

28 comments to Logidy EPSi Review:
The First Customizable Convolution Reverb Pedal

  • el reclusa

    ok. I’m sold. Since I am basically an at-home player these days, most of the limitations are no big for me. And, when I return to the land of gigging, it would be awesome to have a clone of, say, my cranky and fragile old Kay reverb tank without carting it around. Brilliant!

    I’m glad the piece of music from the Cathedranola demo made another appearance!

  • I broached the subject of live use with Oliver and he pointed out that you can load different card with just the reverbs you need for a specific gig and step through them. As I can't imagine using more than four to six for any given gig that seems workable.

  • joe

    But you can’t step backward. I love this thing, but really, that’s an area for improvement. And LOL — I probably use at least 50 IRs per Mental 99 set. Though that doesn’t qualify as normal-person usage. :)

    • joe

      Let me say that more clearly: You can’t change patches via footswitch, period. You must dial to the desired patch number, and then press the enter button. As you can see in the video, the scrolling moves fairly quickly, and it’s easy to overshoot your destination. Dialing between adjacent patch numbers is especially finicky. Seriously—don’t plan to dial in that big chorus reverb during the two-bar drum fill that precedes it, and then toggle back to the drier verse sound 16 bars later. Yes, preparing a “my favorites” SD card as inventor Olivier Limacher suggests is a fine idea, but you must still bend over, scroll gingerly to the precise number, and then press enter. There are probably some players coordinated enough to do that quickly and consistently onstage, but I’m not one of them.

  • Joe Gore

    But you can't step backward. I love this thing, but really, that's an area for improvement. And LOL — I probably use at least 50 IRs per Mental 99 set. Though that doesn't qualify as normal-person usage. :)

  • John Karr

    I am sending this to Jim from the MERMEN who is the god of all things reverb.

  • NicPic

    This thing sounds really nice!…I just wish it had the flexibility of a Strymon Big Sky. But of course it wouldn’t be as cost friendly. I’m sure the R&D dept is cooking up something more radical as we speak. But after forking over 600 bucks in the last 2 months. One for a new pair of glasses I sorely needed and a new/used Amp. Wich by the way has surprised Me the more I’ve played through it. I need to buckle down on the spending LOL! Again Joe. Super demo..And damn,Joe…your boomy clean sound never ceases to amaze Me. I just love the fat rich tone you get. The verb makes a great addition.

    • joe

      Thanks for the nice words, Nic!

      The Strymon stuff sounds great, IMHO, and is more attuned to gigging needs that EPSi. The big thing about the later is the ability to load your own sounds, including ones that you’re never likely to find on a pre-programmed reverb device.

  • Another cool thing with convolution is that you can modify your guitar sound with any sound you record—not just reverbs. I used Izotope Trash's convolution option to run my guitar through a recording of my nerves being tested. I made the Doctor's assistant record the blips and beeps to my iPhone off of the testing machine loaded it in, ran the guitar through it and wow—trippy.

  • Oinkus

    That is pretty neat and nifty ! Can’t believe you don’t have an amp with an effects loop ? I don’t have an amp that doesn’t have one ? I don’t think it is required for it to be in front or behind a preamp to sound good , just has to fit into the sound YOU like right? There is pretty much no way to determine where a sound comes from so I wouldn’t worry about being sued by Fender. (Not that those types of companies are above heavy handed litigation)

  • Dang it. Well, by the time I can budget one, maybe they’ll be up to v2.

  • smgear

    great demo Joe! I linked my piddly post back to here. This pedal is fast moving up the ‘buy’ list…

  • NotSoFast

    The being sued by Fender thing is intriguing. That same reverb sound appears on a million recordings and who knows how many live acts. The purpose of the reverb circuit is to make that sound. Capturing that sound is apparently legal for performances, no matter what frequencies and amplitudes are put through it. Running a scan of all frequencies, capturing that, and then reverse engineering the sound itself still boils down to playing something through the reverb circuit. A fifty year old circuit at that.

    Ah well, the whole convolution thing is really cool. I’m surprised that isn’t patented.

    • joe

      Yes, there are many interesting ethical and legal complications! I believe Sony innovated this technology back in the ’90s with expensive rack-mount processors, but it seems to be in general circulation now. I’m sure there’s a behind-the-scenes legal story there.

      It’s difficult to discuss intellectual property issues coherently because the laws are so incoherent! I happen to believe that, in general, the laws tilt way too far in favor of wealthy copyright holders. I wouldn’t argue that creators ought not retain certain exclusive rights relating to their creations, but just try making sense out of which particular areas “merit” protection, and which don’t.

      You can’t copyright a timbre, yet my sometime boss Tom Waits won an important legal decision when he successfully sued the creators of a TV commercial featuring a singer who sounded like him. They didn’t use Tom’s words, tunes, or recordings, yet the distinctive character of Tom’s voice was judged to be his property. It doesn’t seem a huge leap to ask whether the distinctive sound of a Fender reverb should belong to Fender. (I feel strongly that it should not — but then, I disagree with many rulings on these issues.) BTW, Tom’s beef wasn’t that someone sang in a voice similar to his — the problem was that viewers might assume Tom had recorded a TV commercial, and Tom fights tooth and nail against any commercialization of his art. (Hey, no one ever sued Joe Cocker for mimicking Ray Charles.)

      With some IR reverb plug-ins, all that’s necessary to copy the library is to find the folder where the IRs reside. For example, one could load all Apple’s Logic and GarageBand IRs into a device like EPSi just by dragging the files into a utility that can convert them from AIFF to WAV format. However, Audio Ease’s Altiverb, the leading IR plug-in, copy-protects all its IRs. I think that’s fair—creator Arjen van der Schoot has spent many years traveling the world to capture amazing impulse responses, from Bill Putman’s famed Ocean Way echo chambers to the Sydney Opera house to the interior of the Great Pyramid. He didn’t create those ambiences, but he invested much time, money, and passion in making them available. If you could simply copy Arjen’s amazing libraries into any shareware IR reverb, there would soon be no Altiverb.

      But let’s put Arjen and Fender together: The copy-protected Altiverb library includes many IRs created with brand-name gear, including a Fender spring reverb. I know this for a fact, because I made that IR and donated it to the Altiverb library. I gave Arjen carte blanche to use it, along with some other spring reverb IRs, just ’cause I love those sounds and want to hear them on more music. I’m 100% cool with how Arjen has handled the situation, and I’m happy to support his efforts by purchasing his software.

      Now, if I wanted to add that reverb to EPSi, I could get the amp out of storage and record the impulse again. Or I could just load an impulse tone into Logic, play it through Altiverb’s Fender sound, and save the result in the proper EPSi format. If I do that, am I ripping off Arjen? Would the answer be different if I hadn’t donated the sound in the first place? If I hand’t paid full price for my copy of Altiverb? What if I created the IR file in a studio with a legit copy of Altiverb? What if the studio had an illegal cracked copy of the plug-in? Slippery, slippery slopes!

      Software plug-in licenses invariably grant purchasers the right to use music created with those plug-ins without paying royalties. (If you use a Fender spring on a record, you don’t pay Fender a royalty either.) If you play your guitar through Altiverb on a hit record, you don’t owe Arjen anything—the recording belongs to you, or whoever hoodwinked you out of your copyright. But if I play a one-sample spike through my copy of Altiverb, do I not have the same right to use the resulting recording as I wish? I don’t know!

  • NotSoFast

    Any legal system skews to the advantage of entities that can afford the lawyers. Tom Waits can afford to pursue it. I worked at a game producer and they put out promotional end caps for a title using art that looked a lot like Jeff Goldblum. He sued and won. A friend of mine who submitted a song for a tv show lost the bid but then heard something very similar to his song used for the show… he lacks the resources to pursue it. All this stuff is clearly wrong. Apple and other Software companies conspired to prevent movement of software engineers. The lawyers get half of the payout – the rest is split among the tens of thousands of afflicted. Here’s your $20 – if you agree not to sue on your own ever.

    Altiverb recognizes the difficulty of the situation and has chosen a “non-legal” method, copy protection, as a more advantageous approach. Besides the technical barrier (which in this case is nearly nil) cracking copy protection itself is often a violation and easier to prove and prosecute. Sometimes the protection is just a trip wire.

    It gets really silly. Illegal t-shirts with cracking code on them. Amp simulators that use wink,wink nudge, nudge names like “Classic American”. Japanese Strat-copies sold on eBay as “vintage pre-lawsuit”. Its all obviously stupid but its all we got.

  • joe

    Yep. +1 on pretty much everything you just said. :)

  • NotSoFast

    Interesting times.

  • Miller

    Am I right in thinking that this would allow me to setup a complex effects chain and ‘sample’ it?
    For example if I knew someone who did a lot of laptop processing in the studio, but played live with an old school pedalboard – would this be a good solution?

    • joe

      Answer: maybe, with a strong chance of no. It depends on the particular effects. Also, these are static “snapshots” — if they nature of the effect changes dynamically — varying what it does as you play differently — the sampled IR won’t be able to mimic that behavior.

  • el reclusa

    Placed my order today. Reeeeeeally looking forward to it. :)

    • el reclusa

      Wow- that was fast! Had no idea Logidy was just a couple of hours away from me. Hoping to get a few minutes with it later this evening. I haven’t been this excited for a pedal in a long time!

  • BTW, in case you missed it, Logidy has an updated firmware version c that is tweaked for cab simulation IRs. Free download. More details and review here: http://frugalguitarist.com/post/2014/04/08/Logidy-EPSi.aspx

    For recording and using modelers and preamps live, that’s a handy thing. Increases the value proposition a lot. Definitely on my to-buy list now.

  • Jermaine Eyum

    Based on my understanding of the principles involved here, a convolution pedal would not be effective modeling the following effects:

    Distortions
    Compressors
    Chorus/flangers/tremolos
    Ring modulators

    Nevertheless it would do SOMETHING, and I wonder what that could be. And could it be musically useful even if it wasn’t what you had in mind when you started? I’m not curious enough to buy one to find out, but I’m curious enough to ask.

    • joe

      Yes, everything you say is pretty accurate — including the part about doing SOMETHING, and that something can be hard to predict!

      I don’t suppose you use Apple’s Logic Pro DAW, do you? A little-known feature is one of the best tools I’ve found for grasping what IRs can and can’t do. Among the presets for the Space Designer impulse-response plug-in is a folder called “Warped.” Inside are dozens of experimental IR files such as noise bursts, synth waveforms, and such. Auditioning them is … well, I can’t exactly say instructive, because the results can still be completely unpredictable even after much experience. But it’s pretty cool.

      • Jermaine Eyum

        I don’t use Logic, though somewhere in the pile of unused audio apps around here I may have something that can do convolution. Regarding the “IR Files” you mention, it sorta depends on how those are typically used. You’ve spoken of using a tone sweep to generate an impulse response. But a tone sweep has to be converted mathematically to literally be an impulse response.

        I had an architectural acoustics class back at university and did some really rough estimation of lecture hall reverb times using a spring loaded clipboard and a stopwatch. THAT’s what I think of as an impulse response. The “best” reverb impulse response was felt to be white-noisey, devoid of detectable discrete echoes.

        So I wonder if the IR files generally used by either the pedal software or Logic are really impulse responses or are they instead tone sweep recordings?

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