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APL 1012 - 10ch FIR-based DSP - Review

41K views 246 replies 37 participants last post by  Hanatsu 
#1 · (Edited)
Few years back I reviewed the APL software and APL1 hardware unit. I already concluded that the APL had a great algorithm to calculate the system sound power response. The APL1 unit is a two channel equalizer which connects in series before the DSP unit in a typical car audio system. You can read the full review of it here (it's a bit related to this, the measurement part is discussed in detail there...):

APL1 Review


With that said, here's the review of the 1012 DSP:

Before I installed the 1012, I used a MiniDSP C-DSP and an APL1 for input EQ. It worked fine but it's always a bit tedious to setup two different processors. For years now I've tried to create a perfect coherent stage in my car but to pull some of things off, like correcting subwoofer delays - you require a lot of processing power with FIR-based filtering. Getting the acoustic crossovers right is also a challenge, often there's cancellations in the stopband of the HP/LP filter and this does affect the stage more or less depending on setup. To attain a "perfect" acoustic crossover, you need two set of speakers (midrange/tweeters for example) that both operate in their optimum sound power range and got a flat response in each respective area before equalization. For a 3" driver the sound power response is optimal to slightly above 3kHz (the driver got a frequency response that's omnidirectional into all axis).

You can attain an optimal power response in the crossover stopband in two ways basically, one is to lower the crossover frequency and the other is to use steep slopes (tall order filters). The drawback of lowering the crossover frequency is that you need a tweeter (in this example) that goes lower without audible distortion. The drawback of using tall order filters with conventional filters is that you get massive phase distortion (group delay). If you got a setup like mine with tweeters that doesn't like to go very low using tall order filtering is the preferable option. Now to the point... The APL 1012 gives us tall order filtering with the option to completely eliminate the delay caused by the crossover. With this we can perform pre-equalization of every speaker in the system and then place the crossovers on top of the equalized response to attain a near perfect controlled rolloff into every axis. This is very important since the majority of the sound we hear in an automotive environment comes from reflections that cannot be equalized individually (of course).

That's the theory and I must say that it really does work in practice as well. Even though I had put a lot of time into setting up my old system, this processor did wonders when it came to staging. Most likely due to more powerful equalization and optimized crossovers. Within half an hour I managed to get a better sounding setup than the one I had before with little effort and I haven't even made the post-corrections yet. The idea is that you can setup EQ and crossovers/delays then run the measurements once more to get a more accurate response. A quick TDA measurement showed that multiple small issues had disappeared, primarily in the midbass/midrange region. After the first listening session I noticed that the stage both jumped upwards, got some improved depth and that midbass/sub integration was as good as I've ever had in my car. With a balanced subwoofer volume the upfront bass is amazing now, stage stays stable with most content.

Having said that - A processor, no matter how good cannot be a substitute for a good install. (Just felt obliged to clarify that fact). ;)





Anyways, the APL1012 in comparison to the APL1 is complete DSP with EQ, crossovers and time alignment which eliminates the need for an external DSP as you required with the APL1 unit. The version I have features ten output channels, two analogue inputs and a SPDIF input but there's a version available that also got TOSlink. With 10 channels you could either run a 5-way setup or a common 4-way with rear channels for ambiance etc. The unit got more processing power than most DSPs on the market with cascadable FIR-filters for each channel with 4096 taps available at the moment (it's the firmware that's the actual limitation in the current version). Crossovers are 4th or 8th order and both linear phase and minimum phase filters with group delay compensation are available. You can use the built in equalization function to generate target curves (global EQ) or EQ individual channels. You can also use up to 45ms of delay for each channel which is really good for rear channel experimentation or subwoofer GD compensation. Since the DSP is FIR-based you can also experiment with linear phase filtering. For instance, you could basically make a zero delay vented subwoofer output, I would wait until there are more taps available on the subwoofer channels for increased accuracy though.

The process is pretty simple. If you are familiar with the APL1 unit, you know how the filters are generated in APL Workshop or TDA EQ. For the APL1 unit, the filters are stored in left and right channels to be used as input EQ for each side respectably. In APL1012 unit, each of the filters are instead used per channel (per speaker) and the crossovers are applied on top of these filters. The big advantage of this is that you actually EQ each channel individually before you cascade the crossover on top the filter, this way the stopband will be perfectly equalized with no phase nulls in the actual acoustic crossover region. You can either invert the IR or use the built-in group delay compensation function to cancel out the substantial delay of the tall order filters.

(To clarify, it runs the full APL equalization on EACH speaker)

While working in the C5 software you don't need to upload filters manually as you got the option to directly control the units from the software just like any other DSP software. The software is pretty straightforward to use once you get the hang of it. The software caters both to the less experienced and the advanced user with the cascadable filter option.

The actual hardware are high quality as usual with respectable brand components internally. You can connect volume, sub gain, balance pots and an input selection switch from the two external mini XLR ports which are an improvement over the previous units where you had to open up the chassis. Volume and subwoofer pots are smooth and work really good in a 'linear' fashion from 0-100% output, I believe you get around 6m (~18ft) length of cable. The EQ mode switch work just the APL1 with the exception that modes 1 through 5 are reserved for each set of output filters, still you got 16 modes in total so there's plenty available if you wanna swap between different EQ curves or filters. It also got balanced RCAs which eliminates ground loops if you ever should run into that problem.

All in all I highly recommend this unit, used right it offers (in my opinion) the most processing power available among any of the readily available DSPs. It's a sizable unit compared to many other DSPs but I like the simple and clean design of the unit but it shouldn't be too much of an issue to find a spot for it. I don't think anyone would be disappointed with this unit and it will probably take a while before you feel the need to upgrade to anything else...

A manual is included this time around, it describes what the various functions in the software does so don't worry too much about setting it up ;)

For price, please contact Raimonds Skuruls. As far as I understand the price is different as units are built with somewhat different features and some accessories like the external controls are optional.

Here's some pictures of the packaging (I let that speak for itself) and the included C5 software:





Here's how the C5 software looks:

(Main window where you upload all your filters, manage delays, muting etc.)

It accepts *.fir / *.wave files (Workshop, TDA EQ format or an IR as wave). Details about workshop is in the APL1 review <<



Crossover section, you choose your crossover points and the lowpass/highpass are placed at the same place. No need to mess around with different crossover settings/slopes in this type of setup. Here's a standard 4-way setup with minimum phase crossovers (you can also choose linear crossovers in the dropdown menu).



Every time you upload a filter you get to see the frequency response, phase, group delay of the actual measurement. You can also view all curves of the different speakers in a separate graph window.



Here's an example how you can use the volume, sub and EQ mode switch. I simply set my headunit on a fairly high output (below clipping of course) and use the controls directly connected to the DSP.



Even though it's in the manual, I will write it here as well. When using the C5 software, do not, I repeat not use space or any special symbols in any of the filenames, project folders etc. It kept me busy for a while when setting up my system, safe to say... I will do a separate little video how to measure and how to use the software in the how-to section later!

At the time of writing this, the unit isn't included on the website. Here's a link to the official APL website: http://aplaudio.com/conc2/

Raimonds is also active on this forum, so you could PM him directly.
 
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#2 ·
Wow that's nice. Is that 4096 taps available per channel?!
 
#4 ·
Sounds REALLY nice!!!

Can you provide the dimensions and at least ballpark the price??

Do you know if the APL C5 software works on Windows Vista 32 bit (c 2006)??

Do the 3 knob controllers come with the unit or are they something you built??

TIA
 
#8 ·
Sounds REALLY nice!!!



Can you provide the dimensions and at least ballpark the price??



Do you know if the APL C5 software works on Windows Vista 32 bit (c 2006)??



Do the 3 knob controllers come with the unit or are they something you built??



TIA

Works on Win7. If a Mathlab 2013 8.1a runtime version is available it should work, there is a 32 and 64bit version of the software. Dimensions are 297x210 maybe 60-70 high. I’ll check later, no idea what it costs, sorry.

The three potentiometers came with the unit and there’s plastic knobs included but I bought other ones instead. I built the holder myself though.
 
#5 · (Edited)
Looks great. Thanks for the excellent write-up! :thumbsup:

THIS is what I was waiting for and hoping the APL1 would evolve into. :) Nice work Raimonds! :thumbsup:

I would also like to know the Length x Width x Height dimensions if you have a moment to measure. ;)

Also, what is the pixel resolution of the software window? Is it scalable?
 
#7 ·
Looks great. Thanks for the excellent write-up! :thumbsup:



THIS is what I was waiting for and hoping the APL1 would evolve into. :) Nice work Raimonds! :thumbsup:



I would also like to know the Length x Width x Height dimensions if you have a moment to measure. ;)



Also, what is the pixel resolution of the software window? Is it scalable?


I think it’s 297x210 can’t remember height right now. It’s almost fullscreen on my laptop with 1680x1050 res, haven’t tried to scale it. Will have to check that ;)
 
#9 ·
You can safely assume it'll be in the 1-2k price line. Guaranteed. Though atleast the software comes with it this time. That's nice.

UI is still garbage, with the price he puts on these. You would assume they would fix that without the excuse of "its for professionals"
 
#16 ·
Not sure it does nearly what an LM44 would do, but I see the price / value comparison you’re making. It’d be nice to see a toslink input.
 
#23 ·
Designing a pretty GUI takes time and costs money. I'm in a similar line of work and I agree. I've seen far worse interfaces on much more expensive systems.

I'll take functionality any day over spending more money on something that really isn't needed for the task.

At least it's not command line driven.

Sent from my SM-N920P using Tapatalk
 
#31 ·
Yes, their C-DSP 8x12 has FIR compatibility however the dev team has yet to release it in a firmware update. It says it in the spec sheet: “IIR/FIR (depending on plugin)”.
 
#44 ·
I like how these can be ordered a la carte with some different options.


Is there any way the manual can be posted here so that I can take a look at it? I'm an APL1 owner now and of course very interested in this unit. I could potentially ditch my current DSP and use this as my single solution.


Also, regarding the output delay...I know Hanatsu you had mentioned it does 45ms delay. The software allows you to input up to 100ms. Is the limit actually 45ms or 100ms? That's a nice improvement over most available dsp's.


And also, what is the output voltage on the RCA outs?




Thanks!
 
#45 ·
more importantly whats the input voltage
 
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#47 ·
I too have been in contact with Raimonds. I look forward to getting my processor from here. Possibly...This or a DBX solution.
 
#65 ·
Not to knock Raimonds, but he seems to operate in the same way a lot of the Pro-A/V world operates: No manuals

Last week I finally went to a class to learn a pice of software I've already been using for three years. It just seems like the way things work in the Pro-A/V world.

I *should* have some time to work something up next week, if I do I'll run it by Raimonds for accuracy before posting it.
 
#67 ·
May I ask what are the drawbacks to a fir filter
Added noise, group delay, solution artifact ect... if any..
...
One drawback might be that some understanding of DSP theory would be needed to really make the most of it.

On the flip side it means that one may not need to understand convolution, or the maths behind the filters, but certainly understanding the fundamentals of what is happening are an advantage.

If one was a EE using MATLAB, then it would be ideal... and if one was theory adverse, then it may not be an advantage unless they had an installer with was familiar with FIR based DSP theory.

But I may be somewhat biased...
 
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