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Re: Comprehensive Review: " APL1 " - Advanced DSP / EQ / Phase Correction Unit

Dreams come true


10 channel unit with master EQ on input (12 FIR cores) is ready to serve demanding customers : )



OK What does this mean... 12 FIR cores, and 10 channels?
Is the FIR based EQ done on the left and right independently, and then the remaining 5 channels per side are bandpass crossover outputs?

If the EQ is done on the input then what happens in the passband? It seems like ripples would be different on the low-side and high-side speakers, so the phase correction would need to be different on each speaker??

And it sort of seems like it is similar to a DDRC-88A, but with access to the FIR filters - or am I wrong?

Also, I could not exactly see this on the APL home page.
 

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Re: Comprehensive Review: " APL1 " - Advanced DSP / EQ / Phase Correction Unit

OK What does this mean... 12 FIR cores, and 10 channels?
Is the FIR based EQ done on the left and right independently, and then the remaining 5 channels per side are bandpass crossover outputs?

If the EQ is done on the input then what happens in the passband? It seems like ripples would be different on the low-side and high-side speakers, so the phase correction would need to be different on each speaker??

And it sort of seems like it is similar to a DDRC-88A, but with access to the FIR filters - or am I wrong?

Also, I could not exactly see this on the APL home page.
Thank you for questions!

You should compare results of mentioned “similar” solution in fields of car audio competitions and pro audio. And how much they trust themselves in terms of investment to develop own hardware.
.
You should also check how far in “moon shining” they are from original work
https://www.google.com/patents/US8121302
published at May 18, 2005

Real competitor products are Dolby Lake and Fouraudio HD2

Thanks to Elgrosso for pointing to preliminary press release on APL’s facebook

FIR based EQ should be done in each of bands.
Then final FIR based EQ should be used on overall system (master EQ on input) to fine tune small residual crossover tuning errors and to use any targets.

10 channels means 10 analog output channels.
12 FIR cores means 12 independent FIR filters with 4096 taps each (in first release, later will be more, especially for 96 and 192kHz versions)
Any of FIRs can be any kind of filter and are not tighten to some bandpass or else.
As example, the unit can be configured as 12 channels EQ

The detailed correction of each speaker makes crossover “ideal” with complementary ripples, amplitude and phase responses. This actually is making all the value for use FIRs on each band.
 

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Re: Comprehensive Review: " APL1 " - Advanced DSP / EQ / Phase Correction Unit

Thank you for questions!

You should compare results of mentioned “similar” solution in fields of car audio competitions and pro audio. And how much they trust themselves in terms of investment to develop own hardware.
.
You should also check how far in “moon shining” they are from original work
https://www.google.com/patents/US8121302
published at May 18, 2005

Real competitor products are Dolby Lake and Fouraudio HD2

Thanks to Elgrosso for pointing to preliminary press release on APL’s facebook

FIR based EQ should be done in each of bands.
Then final FIR based EQ should be used on overall system (master EQ on input) to fine tune small residual crossover tuning errors and to use any targets.

10 channels means 10 analog output channels.
12 FIR cores means 12 independent FIR filters with 4096 taps each (in first release, later will be more, especially for 96 and 192kHz versions)
Any of FIRs can be any kind of filter and are not tighten to some bandpass or else.
As example, the unit can be configured as 12 channels EQ

The detailed correction of each speaker makes crossover “ideal” with complementary ripples, amplitude and phase responses. This actually is making all the value for use FIRs on each band.
Ok
1) What happens on Subwoofer channels?
I think that ideally one would filter-decimate the sample rate down... but I suspect that all the cores run at full sample rate.
So should I be concerned with filter resolution in the subwoofer band?

2) would I still need something else to do time alignment?
Or is time delay conceptually the same as rotating the taps to the right or left?

3) What is this unit called?

4) What is the Euro price?

5) is it available now? Or when it is to be released?

6) how does one start? As in what software tools should I get for use in OSX?
Or do I need to run windows in a VM?
 

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Re: Comprehensive Review: " APL1 " - Advanced DSP / EQ / Phase Correction Unit

Ok
1) What happens on Subwoofer channels?
I think that ideally one would filter-decimate the sample rate down... but I suspect that all the cores run at full sample rate.
So should I be concerned with filter resolution in the subwoofer band?
You are on the button! I am considering that for 96/192 kHz.
The 4096 taps for 48kHz (85ms ir) is pretty much ok

2) would I still need something else to do time alignment?
Or is time delay conceptually the same as rotating the taps to the right or left?
C5 software is managing this in exactly mentioned way.

3) What is this unit called?
APL1012a
4) What is the Euro price?
negotiated from deal to deal

5) is it available now? Or when it is to be released?
Yes, please make your order!

6) how does one start? As in what software tools should I get for use in OSX?
Or do I need to run windows in a VM?
I’m seriously considering it!
Any plan to port your soft on mac?
1) You need Workshop or TDA EQ for basic measurement.
2) TDA - for crossover tuning, time alignment
3) C5 - for all the management.

You will need Windows on VM for Workshop to run on mac.
TDA series programs and C5 can be ported to mac with
pretty much not so big effort.
But it depends on your (customers) support to this project.
It was considered as some kind of "kikstarter" project at August last year.
Now, it is ready for orders without that.
But anyway, your early orders will help a lot.
 

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Re: Comprehensive Review: " APL1 " - Advanced DSP / EQ / Phase Correction Unit

OK...

Q7) So would subwoofer management be a software implementation - with some filter-decimate brickwall convolution 'pre-stage' that can happen in the future?

Q8) Are the DSPs cores fixed point or floating point?
I have an analogue radio/CD that I was set on using... But then I got a new (used) unit that has a digital out?
The amps are old school jobs that are on RCAs, so I am thinking about whether I need to worry about low level signals and whether at quieter volumes I will be running out of bit depth... (The higher sample rates should help) The new radio/CD does 24bit CDs, but I have no idea what happens with the aux inputs from say an iPad, or an iPad into a GPS-aux input with a bluetooth phone, and then all the mess back into one of the radio's 2 aux inputs.
 

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Re: Comprehensive Review: " APL1 " - Advanced DSP / EQ / Phase Correction Unit

1) You need Workshop or TDA EQ for basic measurement.
2) TDA - for crossover tuning, time alignment
3) C5 - for all the management.

You will need Windows on VM for Workshop to run on mac.
TDA series programs and C5 can be ported to mac with
pretty much not so big effort.
But it depends on your (customers) support to this project.
It was considered as some kind of "kikstarter" project at August last year.
Now, it is ready for orders without that.
But anyway, your early orders will help a lot.
Very interesting!
C5/TDA running on mac, that’s the trigger I needed.
Workshop I'm ok to play it on VM as it's not so often.
Ok then email now, thank you Raimonds.
 

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Re: Comprehensive Review: " APL1 " - Advanced DSP / EQ / Phase Correction Unit

OK...

Q7) So would subwoofer management be a software implementation
Anyway, it must be hardware.
The good idea is to use as short FIRs as possible - to have as small "time smearing" as possible. 4096 taps can be sufficient for sub processing with that in mind.


Q8) Are the DSPs cores fixed point or floating point?
They are no floating point as we know that from computer science.
They are floating point in terms that the point is floating to keep max accuracy for all computation - no quantization used till output.
 

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Re: Comprehensive Review: " APL1 " - Advanced DSP / EQ / Phase Correction Unit

Safe bet, it’s too easy to spend time on a target even if we know we have other issues uncovered.

About the loudness compensation, I tried this some time ago when I first got my horns and used to listen loud:


3 settings basically:
- for 70/75db > boost low and highs
- for 85/90db untouched
- for 100db cut low and highs

The lowest one was useful, brought up some depth and details while keeping it confortable.
And the highest one didn't really work as intended. I realized that the road noise was naturally masked by the loudness effect at high level (high level means usually high speed for me).
So the compensation on the highs was good, but the low end should have been let untouched.
Well anyway I drop the idea as I just don't bother with settings for that now, and just listen to more reasonable levels.
But I would appreciate if someone builds this feature in a box, or a plugin.
Ok ^that^ is pretty slick!


Anyway, it must be hardware.
The good idea is to use as short FIRs as possible - to have as small "time smearing" as possible. 4096 taps can be sufficient for sub processing with that in mind.
...
I saw on the C5 photo that the sample rate was selectable for each channel. If there was a ADC running at 4K, then one could probably do the subwoofer with 256 taps? Or do all the channels need to be the same sample rate? (I understand aliasing and Nyquist theorem.)

...
They are no floating point as we know that from computer science.
They are floating point in terms that the point is floating to keep max accuracy for all computation - no quantization used till output.
Ok - I did not do computer science at uni, however I seem to be doing it most of the time. I recall Estonia having the best internet in the world (a few years ago), so I assume Latvia is similarly advanced in technology? - based just on proximity alone.
 

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Re: Comprehensive Review: " APL1 " - Advanced DSP / EQ / Phase Correction Unit

How soon can we expect the car version of the APL1012 to be available for purchase? Any pricing yet?

I’m going back and forth between going with APL-1S unit or the Dirac DDRC 22D or DDRC 88a. This car version APL1012 seems to be the most ideal!!
 

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Re: Comprehensive Review: " APL1 " - Advanced DSP / EQ / Phase Correction Unit

Nice Raimonds!

Is there a connection for the ribbon cable of the preset switch on the outside of the enclosure?


-Steve
 

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Re: Comprehensive Review: " APL1 " - Advanced DSP / EQ / Phase Correction Unit

Nice Raimonds!

Is there a connection for the ribbon cable of the preset switch on the outside of the enclosure?


-Steve
I wouldn't be surprised if it's the same as the APL1, where the ribbon cable is sandwiched between the lid and the rest of the case.

I do need to get more info from Raimonds about how to make a simple 2-tune switch from the ribbon cable.
 

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Re: Comprehensive Review: " APL1 " - Advanced DSP / EQ / Phase Correction Unit

...I do need to get more info from Raimonds about how to make a simple 2-tune switch from the ribbon cable...
I'll get you started. I was going to do something similar, because when will I ever need 16 presets?

He sent me the pinout for the rotary knob. I haven't had a chance to take it past that, though.

His response about the pinout:

"Yes, you can use any multi-conductor cable and no need for shield.

Actually working wires are 5.

*

Here is cable's pinout

*

1 signal 1

2 ground

3 signal 2

4 ground

5 not in use

6 ground

7 signal 3

8 ground

9 signal 4

10 ground





Sent from my SM-N920P using Tapatalk
 

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Re: Comprehensive Review: " APL1 " - Advanced DSP / EQ / Phase Correction Unit

How soon can we expect the car version of the APL1012 to be available for purchase? Any pricing yet?

I’m going back and forth between going with APL-1S unit or the Dirac DDRC 22D or DDRC 88a. This car version APL1012 seems to be the most ideal!!
It is available! Please make your offer : )

Nice Raimonds!

Is there a connection for the ribbon cable of the preset switch on the outside of the enclosure?

-Steve
YES! You can see two mini XLRs on back panel. The 5 pin one is for preset switch. The 3 pin one is for remote volume control.

I also noticed that there is no optical input?
The optical in is available on main PCB temporarily.
 

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Re: Comprehensive Review: " APL1 " - Advanced DSP / EQ / Phase Correction Unit

APL1012 - Great device! Especially for those who will make 3-way active install. As I understood, appart from the preset switch, there is a separate volume control for the whole system. Or for subwoofer channel only?

Looking forward to install it in a new car.

Recently I have read an article by Chris Huff "Seven keys to making voices sound like you want them to sound" published in Church Sound 3/2018 and it reminded me some discussions about the target curve called mp1 from Rajmonds Scuruls.

Recommendations mentioned in this article are quite simple, but after their implementation, you will be surprised of how the shape of the final frequency response curve looks like. it is almost similar to the above mentioned target curve mp1. And it makes sense.
 

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Re: Comprehensive Review: " APL1 " - Advanced DSP / EQ / Phase Correction Unit

I was planning to upgrade my processor and have finally decided to buy either APL1 or 1012. Already in conversation with Raimonds on the purchase.

I am in two minds...whether I should buy 3 units of Apl-1 or 1xAPL1012.

3xApl1 should give me more freedom of use. My existing processor is alpine pxa-h800 which can do active 3 way front+ sub and also multichannel 5.1 surround (2way front/centre/rear/sub)

Having three units of Apl-1 will give me 06 channels of analogue input and 6 on output. They can used in multichanel surround system also. 3xApl can be placed between pxa-h800 and the amps.

Similarly I can use them in my HT also for testing the differnce in sq. At least front/center/sub and a pair of surround out from my Av-processor can be processed for eq with Apl-1. :)

My current car setup is 3way active front + sub setup.
1xApl1 can be used for mid range + tweeter (with passive crossover)
1xApl1 can be used for midbass
1×Apl1 for sub (or rears if I add later)
All 3 units can be placed between my existing dsp and amps. Crossover and Ta can be managed from the dsp.

1xAPL-1012 will give more control in a 3way active front + sub+rears.

Considing the flexibbility 3xapl1 will provide, will Apl-1012 provide any major noticeable benefits in sq?

Pls help me in deciding.

Thanks







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