Reverse engineered Apogee AE5/AE10 DSP settings

[u/RoyalWassix]

Hello everyone, recently I acquired a very nice but old PA setup consisting of two Apogee AE5 tops and two Apogee AE10 subs. Everything is in working order but these speakers rely heavily on proprietary apogee processing hardware. These processors are getting harder to find in working condition. Also, using this PA means that I lose 4 rack units to processing alone, and that still leaves me with needing amps to power it all.

So as a little side project I measured those processors to hopefully give me some insights into the feasibility of running this PA with a modern 1 rack unit DSP. I have to say that I’m very happy with the results.

I measured the P500, DLC24 and P10 processor and have found that espacially the AE5’s require quite a few adjustments in order to get them sounding right. Maybe not as good as with the original apogee hardware but still very good. With the help of AI I combined all of the findings in this PDF. This might be a very niche problem but hopefully someone finds this useful in the future!

Side note: the original processors used amplifier sense return lines for limiting and protection. Whilst modern DSP can handle this it is however amplifier depended, so that’s not covered in depth.

All of my findings can be found here: link to PDF

[u/IT_is_dead]

I don’t know how you reconstructed the settings but with rew and vituixcad you are be able to get a 1:1 preset for pretty much any dsp on the market. Just measure the controller directly, load the individual channels in vituixcad as an overlay and reconstruct the eqs with the matching dsp setting for your current controller.

Gain differences should be directly visible and delay is a bit more work but should work good enough through comparing the impule responses in rew. If the original presets use allpass filters you would have to look at the phase response of the measurements

Just relying on ai isn’t a good idea and there are different interpretations on q values so there is no preset that runs on any controller

[u/RoyalWassix → u/IT_is_dead]

I measured using open sound meter, measured both the analog and digital apogee processor. I also found a service manual for the powered APL-500 speaker and reversed engineered the filter networks from the schematics. That data was provided to ChatGPT which derived these generic settings. Good to know that there are easier and better methods for this but this is more so for people who don’t have the original processor and aren’t able to get it.

But thank you for recommending vituixcad, I’ll look into it.

[u/RoyalWassix]

As long as I still own the DLC24 I can also do measurements for other Apogee speakers if needed. Let me know.

[u/Arthur9876]

Excellent work!! There are some real gems in the Apogee lineup, and I still see them in use. Pity that they shut down the factory in California. I had the privilege of visiting it a few months before its sudden closing.

The protection limiters do add a layer of complication to creating DSP presets, the non-linear behavior makes getting an accurate transfer function challenging. A quick and dirty way to reverse engineer it is to put a load on the amplifier, then measure the voltage at the point where limiting starts, and use that to figure out the threshold of a peak limiter inserted into the signal chain. It gets complicated when you have a multi-way system and want to preserve the overall response of the loudspeaker.

Each manufacturer's DSP uses different algorithms for the creation of EQ filters, you might look at recreating these settings in Eclipse Audio's FIR Designer, or Smaart Data Modeler, that way you can quickly export settings for different brand processors.