2x4 Digital Signal Processor

Obviously this is not a beginner toy, and if you don't understand system tuning or have a step-by-step guide, the product is not for you. I also have the 2x4 balanced for my mixing setup and as they have the same set of features, my opinion is the same for both.Yes, this unit can be USB powered. So I didn't bother buying the extra DC adapter, I just use a USB wall plug and the provided mini-USB cable. The only downside is that when I need to look at the settings or re-tune, I unplug the USB from the wall and put it in my computer, so the unit is powered off and back on. Luckily, losing power does not cause the unit to output any voltage spike that could damage equipment! So three cheers for that.It's hard to believe that this can do so much low latency processing, and just WORK. I'm using the 2x4 Advanced plugin. The EQ sounds good, even the output compressor sounds good though I am not using it.Long story short, what this unit does, it does well. Compared to other solutions, this is pennies on the dollar.

This thing is amazing. I use it as a splitter to run 4 subwoofers from my single subwoofer output of my receiver. I also do some minor EQ to get them all working together nicely. I've been told that the 2x4 HD is a little better for running subwoofers so I'm going to order one of those soon and move this back into my bedroom 2.1 setup. I use it to hook up my JBL LSR305 active speakers to an SVS SB12-NSD subwoofer and it handles the crossover as well as some EQ duty to get it sounding nice.

First, there seems to be some confusion regarding Rev A (0.9vrms in/0.9vrms out) vs. Rev B (2vrms in/0.9vrms out). This is understandable as revisions generally mean design changes. In the case of the miniDSP it would have been better to refer to them as Mode A and Mode B, for they can be easily changed via internal jumper.Our application is intended for an in-house design of a high-end 3-way speaker system. We started with a profession two channel 3-way crossover, adjusting the crossover to obtain an initial optimum performance limited by the capabilities of the crossover. We then carefully measured the parameters of the crossover to transfer to the miniDSP; this would provide a starting point, and an immediate performance comparison between the crossover and the miniDSP.While we have not yet performed a formal A/B comparison; the initial reaction was the minDSP duplicated the performance of the crossover to an amazingly high degree. This now gives us a starting point from which we can refine the speaker-system to include component time-alignment, which the crossover was not able to accomplish.The accompanying support/programming software is relatively straight forward, although we did note one occasion where a parameter was set only to find it had reverted back to its default value. The issue may be do to the fact that there are two ways to navigate through the sub-blocks of the miniDSP; direct selection of a block and a sequencing arrow-icon that serially steps through each block. We are still investigating this issue. Also, there may be a slight insertion loss even if both the input and output of a given channel are set to 0dB.We are very pleased with the performance of the miniDSP 2x4 and would not hesitate to recommend it.UPDATE: We discovered a minor issue with the miniDSP 2x4 Output-Delay [version 1.06 (1.6 as displayed within plugin)]. The initial delay increment 0.02083 ms (1/48 Sec), is not sent to the DSP, even though it displays in the plugin. This was detected in two ways; comparing the input to the output; and routing the input to two outputs, delaying only one output and then comparing the delay between the two outputs. There is a simple work around simply increment the delay one more than required will provide the correct delay (as mentioned only the initial delay increment is not sent to the DSP, all subsequent increments are sent. Actual Delay = Displayed Delay - 0.02083 ms). The company has a pre-release update that corrects the problem.We still highly recommend this product.

Let me say this first, I have read reviews that say that you can daisy chain active sub-woofers and it will work. I can attest that daisy chaining active sub-woofers does not work.After having multiple issue with daisy chaining 4 sub-woofers ( Acoustic, Pioneer, KLH ), I decided to look for a solution.1. You can daisy chain if they are the same manufacturer2. They have a separate output or a line-out or pass-thruYou cannot if the above is not met. A simple solution is the miniDSP 2x4. It will allow you to setup up to 4 separate sub-woofer from different MFG.This is very simple. First you need to get the 2x4 Advanced plug-in and then email support to have them unlock the Matrix-mixer, after that you need to setup each sub-woofer separately first. First thing is to set the internal volt to 0.9 V RMS, that is a jumper next to the 2 input terminals inside the miniDSP. For me I choose input 1 > crossover 200 Hz LR 12 DB / Octave > no eq > routing all 4 set to input 1 > no output eq > no gain and all high pass and input 2 set to bypass.Connect a usb microphone to your computer, make sure the microphone has a 20 Hz to 15 Khz response and is certified for testing. Place the microphone at least 1 meter away pointed directly at the sub-woofer, run the spl level test. Try and set the SPL to at least 89 DB / 1 meter, if the sub is not capable then find its highest SPL / 1 Meter, repeat this test for each sub woofer. Once you have all say 3 sub's tested and you have 87, 89. 91, add the 3 and then divide by 3 or 267 /3 = 89, this is you mean SPL. Now we know that sub 1 can only hit 87 DB SPL so we will set are over all output to 87 DB SPL for all three sub woofers, that should give us a mean output of 89 DB SPL overall ( know it sounds crazy but trust me the math works) since i have a Yamaha RX661 receiver that has auto room acoustic built in all you need to do now is run the auto room acoustic, and you are done.Lastly make sure you buy the AC Adapter as you will need to apply power to the miniDSP 2x4.Over of ProductDocumentationThe documentation is confusing, you actually cannot figure out which is the correct plug-in to purchase, you need to send an email to support to figure this out, and there response time is rather slow 2 to 3 day wait. The plug-ins do not come unlocked, so feature even after purchasing are still lock and the only way to unlock is to send an email to support to get them to unlock it another 2 to 3 day wait.The softwareThe software is really straight forward (once you get the correct plug-in), you can do the advance features, if you want to run all the test tones, and graphs to complete it, but for simple crossover you can use the basic and dial-in the frequencies you need and the work up from there, trust me start with the basic and work up from there. Each plug-in cost about $10 which is nice price.HardwareThe miniDSP 2x4 Box is solid, it has internal jumpers, so read the manual before you use it to make sure the jumpers are in the correct setting for your application. It does not come with a AC Adapter but you can get one easily and very inexpensive. the case is metal, the connectors are gold plated, has one power in and a USB-A connector.PerformanceNow as I stated above this will allow you to run up to 4 sub woofers from different MFG easily. And the sound is AWESOME!!!, if you follow how to set it up correctly. I got the info from the MinidDSP website, it will balance the sub-woofers to the same SPL and the same voltage that daisy chaining does not do or allow. Each sub-woofer has it own 0.9 V RMS input and it own 0.9 V RMS output ( it is not shared as in daisy chaining ) , you can fine tune each sub-woofer independently or as a group or as sub-pair ( IN-1 > 1 and 3 with front EQ setting , IN-2 > 2 and 4 with REAR EQ Settings ). It is not only for sub-woofers, it can be a 2-way or 3-way and even 4-way crossover, just depends on the software you use.Overall a good product, documentation needs to be improved, support needs to response a little faster. That is why i am giving it only 4 stars as I had to wait 6 additional days to get my purchase ( after waiting 3 days on shipping) working, and that was only after I figured out that the instruction did not match the software, even after downloading purchasing all version of the 2x4 plug-ins, to only find after contacting support that these features needed to be unlocked. ( the unlock part is NOT in any of the documentation )