I have been working with and listening to the Maag EQ4 in its 500 series hardware and software versions. My mission was to give an impression of the differences and similarities of the products. The reason for this was that I had spoken to Pan about what I had thought was a certain assumption, on my part (and others), that products like these would rarely be compared, since users would be unlikely to afford both the hardware and software, simultaneously. He said I should do exactly that, compare the two, then write an article about what I found. Now, I know there are some who will argue that there are differences in sonic quality between software and hardware and I will give a nod to personal opinions - everyone has one. But, it is my personal belief that there are so many variables in the construction of the signal path between users, that unless the reader and I are using identical equipment in identical rooms, the best we can hope for is only an approximation of similarity. There is no way I can sit here and say that this article is anything more than an opinion and that someone with more money, time, and inclination can make an argument over this.That being said...Pan contacted Maag Audio and reached both Cliff Maag, Sr. and Jr. They agreed to send a couple of the 500 series EQ4's to me for trial. They also made available - through Plugin Alliance - the Maag EQ4 Air Band plug-in. I spoke to Cliff Maag Sr. and asked him why it was designed in the way that it was. He told me that he had always disliked the phase shifting between frequencies on regular eq's. So, in this design, phase shift is minimal. Cliff, Sr., also did not like the fact that when something needed some "shine" in the high end, other eq's just had a "hiss knob". Ok then, the birth of the Air Band and the patent.The plug-in installed immediately, without exception, and with excellent help from the Plugin Alliance staff. The hardware arrived about a week later, very well packed and secured from movement, in the box. On inspection, the workmanship was very good, with clean and solid construction.First Blush - The visual aspect of the plug-in is identical except for two things: a trim pot and perspective. The hardware is built for a 500 series rack and it would be just as easy to read, and actually more like the EQ section of a console.I installed The EQ4 500 series modules in a 500HR rack, patched it in, and was up and running. The hardware has very solid detents for the settings on each knob. The plug-in is horizontally placed and the numbering is across the top in an easy-to-read fashion, as well. I will mention the "mouse madness" that has bothered me in many of the plug-ins I have used. It did behave differently, depending on which DAW I used. Nothing bad, just something I had to get used to. And, I am assuming it has something to do with the DAW's control of the plug-in rather than the plug-in itself .Full speed ahead - For the first test, I put the hardware on the 2 bus outputs, then back into the DAW into two channels so I could split the output directly to my monitors and also record for a later listen. I put the plug-in into the 2-bus FX loop and also into a post fader send and matched gain, so that pushing the in/out buttons on either format gave me the same gain. I did notice that the plug-in peaked a little more, and with a bit of tweaking on the trim control, I was able to match the performance of the peak/signal led monitoring. The plug-in has some nice basic presets - 4 vocal settings, two for female and two for male vocals, Kick, Snare, Hi Hat and (surprisingly) 808 Drums, three for Bass, three for Guitar, and three for Keys. They also included a basic Mix bus setting and a zero. This got me going quickly on the 2-bus. Then the ease of the plug-in became very apparent.I could set up a basic preset and do a little tweaking and be happy. Like all "in the box" tools, you'll get your own settings and save them for future mixes. In my case, I had some very problematic drum and vocal work from some 40 year old tapes I was fixing. The kick and snare presets took me right to the sound I was looking for (nearly), and with very little tweaking, I got them working for me. The vocal was just a little flat and lacked air. I tried all 4 of the vocal presets and one of them took me to the neighborhood that the vocal wanted to live in. That day, relief was spelled EQ4!With the hardware, I took the software settings and duplicated them on the hardware, and then let the monkey loose. The presets were nice spots to start from, and for a first timer, really moved the mix along.My next tests were inserting both units into instrument and vocal tracks on some new tracks. I would have to say that I enjoyed using both the plug-in and the modules. They also performed very well on each of the tasks I had them assigned to. Lead vocals, and in particular, the backup vocals got immediate "air". I really want to address this because it made a huge difference in the quality of the backing vocals particularly.I like the fact that I could dial in the sound I wanted, that in the past, I had to fight to get right. I had my own way of doing it, that was never satisfactory really, and it involved that hiss knob that I mentioned earlier. Drums got punch, cymbals shine, Guitars cut through the mix painlessly, and after thinking about it a bit, the Sub control really does seem to do the same thing on the bottom end that the Air Band does for the top end. Now I understand why they put the 808 drum setting in the presets!Pulling up the skirt - The EQ4 is designed to have each band intimately involved with its neighboring bands. From bottom to top you have a SUB fixed boost and cut bell (10 Hz), 40Hz fixed boost and cut bell (+15 dB, -4.5 dB, 160 Hz Fixed boost and cut bell (+15 dB, -4.5 dB), 650 Hz Fixed boost and cut bell (+15 dB, -4.5 dB), 2.5 kHz Fixed boost and cut shelf (+15 dB, -4.5 dB), Air gain (+15 dB), and Air Band boost only shelf with detents @ OFF, 2.5 kHz, 5 kHz, 10 kHz, 20 kHz, and 40 kHz. WHAT??? 40 K!I can't hear that! - I whined to Pan about that and he said " Try it, you'll feel it, Boss." He's right, I felt it, and at the same time, I heard a shine that I did not hear before. It wasn't that I had ever missed it before, but now my cholesterol levels shot up because of all the butter on the tracks - yum! I will have to be careful not to use too much, now.The beauty in the design is the ability to maintain a tight bond between bands - gain up and gain down. If you have too much or too little overall and want to change it, but maintain the frequency relationships, just take each knob down or up the SAME amount and it will preserve that partnering. No comb filtering, no phase shifting, and Big Air. Really, how many times have you had a setting on your EQ and wanted to add or subtract gain across the board and been dissatisfied with the sound after the change? Not here. You want to go up 2dB? Just take all the knobs and move them up 2 dB. It's that simple, and no change in the sound you had, just the gain.Slammin' Salmon - Hit this baby hard! How much fun is that, when you overdo it - go big - be the great white shark? Sure, you might get hurt - big hook through little finger. Not here. This tool is fun when you are making minor fixes or dropping a bomb. Don't throw away common sense, for crying out loud, but why have something that has this ability and not use it...creatively? I did experiment with over-the-top settings and found some useful ways to use, and abuse the tools. Some were immediately useful and some were...well, some things are best left unsaid. Suffice it to say, if you go looking for trouble, you'll find it - apologies to any whales, elephants, or dogs, for that matter, that I may have offended with injudicious use. (OK, I'll confess. I fired up my little PA - a fire breathing 4 KW - because I wanted to rumble. I just love watching 18" speakers move air.)100 Mile an Hour Tape, Hair product, a mother's love - all have one thing in common - they fix things. And that, is what the EQ4 Air Band does. It fixes audio. It's the piece of equipment you are probably looking for when you're sitting at your desk and the mix just doesn't sound quite right - you know, you've been there. There is just not enough of...uh...something, right? And the EQ4 Air Band, like a mother's love, does it in a kind and sweet fashion. It works in a wide range, through a wide variety of musical genres, and produces results.The Finality of it All - Honestly, I tried to find differences, I worked at it, I A/B'd the tracks to death, I spent hours at it, I tried multiple instruments, l tried poorly recorded tracks, I listened until I had to walk away and give the ears a break. And I found, as nerd-speak would put it in computer terms, as always - GIGO - garbage in garbage out, except here. The EQ4 was like a fine air freshener making even the worst track, at the very least, smell better. And, if you're doing a lot of turd-polishing, you need to have all the help you can get. IMHO the plug in sounds like the hardware. The only thing I couldn't get it to do was fix the performance!IF you are working in-the-box, you will be very happy and you can be rest assured that you will get the sound of the hardware EQ4 Air Band. AND, the best part - you'll have multiple instances of it. I did not find that I suffered any significant CPU loading or latency with six instances to start (kick, snare, guitar, 2 x vocal, and 2 bus - this along with a plethora of other plug-ins I was using). Then, I threw it on all the tracks and the busses for a total of 21 instances. I was going to kill the computer, if I could. I didn't even close.I would love to have a rack of the 500 series modules. I know that I'd be using them all the time and maybe, someday, I will. I really like the detents on the knobs, and I will always love the tactile feel of a hardware unit. If you have the money, you should have at least one of these in your arsenal and preferably two. But, if you are like me and always having to make a choice between a piece of equipment or paying a bill...well, the EQ4 plug-in is the answer. But,don't get me wrong, it's not cheap, but, it won't break the bank either. And considering what it will do for any mix, it is worth every penny. Like I said earlier, multiple instances with little or no latency and CPU hobbling. I can't stress that enough. In these days of software bloat, it is refreshing to see a tool that isn't going to hinder your personal process.