Is the Dirac Research AP20 a SOTA SSP? - Page 8

As for hardware products our main business model is still to let someone else do the hardware, and focus on what we are good at, i.e. software. A good example of a home space hardware product that is on it's way is the DL2 by Karlton Audio, and of course later also the DL3.

We are however going to release on our own purely software based end-consumer product range directed at "computer audiophiles" where Dirac filters can be generated and then run in real time on a PC or a Mac

Please keep an eye on dirac.se the coming months for announcements, I can also contact you personally should you want me to.


The time alignment between subwoofer and main speaker is indeed a very tricky issue. In the AP20, the alignment is based on estimation of arrival times. The difficulty, just as you point out, is the large wavelength of the subwoofer response which makes it difficult to even speak of a distinct arrival time. Another solution is to time-align them so that the best summation in the cross-over region is achieved. That is, to optimize with respect to the sum response. In the present implementation in the AP20, this is not yet implemented. But who knows, we might be working on something...


Best
/Chris

Hi Carl,

Will DL3 include HDMI inputs and volume control?

I don't know if there is even a standalone DSP / room EQ on the market with HDMI... Imagine HDCP!!!!

"Will DL3 include HDMI inputs and volume control"

"I don't know if there is even a standalone DSP / room EQ on the market with HDMI... Imagine HDCP!!!!"

The AP20 has 4 HDMI inputs (with video pass thru) and a volume control.

The DL3 will not have HDMI inputs or a volume control. The DL3 is a straight line Dirac Live processor.

____________
Best Regards,
Carl Huff

Hello Chris,
Thank you for the reply. It would seem a natural computer function to iterate the subs with the mains and other subs. What may not be so natural is to write the program , especially when taking into account the room modes.

From another thread:

There is clearly a genuine need for such a program. After having heard Dirac Live and the AP20 I have complete confidence in your ability to write it!

I just want to clarify a few things.

Is there no chance of NEO X finding its way into the AP20? Forgive me as I am not much of an expert, but video pass through mode means that the information for video is sent directly from the Bluray player? The user manual states that a single mic is not recommended for measurements(obviously for commercial cinemas) but what about for home theaters with a much smaller space? Or is this a separate feature to Dirac live EQ?

The the quote by GGA was about my setup, where I will have two big subs to take care of the below 35hz to "I hope" about 6-7hz and then have the remaining bass above 35hz taken care of by another set of subs. So I will be crossing the subs within the LFE channel. Will this pose a problem for the Dirac live? As I was going to go with a separate low frequency EQ to do this.

"Is there no chance of NEO X finding its way into the AP20?"

I would never say never. What I can say is that there are no formal plans to include Neo X today. However plans change and if there is a market NEO X can be added. The AP20 is a software driven beastie. Software update of the AP20 in the field is trivial.

Yes, video pass thru mode means that the video is passed on untouched by the AP20. Only the audio is pealed off to be processed.

Dirac Live uses a single microphone for measurement. The multi mic reference eludes to a legacy commercial Cinema technique that is supported by the AP20 for those 'crusty old' installers that do not trust Dirac Live and want to use the 3rd octave and PEQ filters that are in the AP20. Dirac Live configuration is done on a laptop computer that chats with the AP20 via WiFi link. The Dirac Live software requires the use of a calibrated microphone and USB mic preamp.

There are no problems with subs and Dirac Live when using the active crossovers and channel management internal to the AP20. However problems do begin to crop up when you attempt to mix external crossovers, bass management solutions and chain subs on a single channel. External gear is a problem because it simply is not under the AP20s control. Multiple subs on the same AP20 channel means multiple targets to optimize. The biggest problem when managing subs with the AP20 is that the AP20 does not include bass management. However that changes in 60 days or so. Bass management will be added to the AP20 in a software update.

When applying the AP20 and Dirac Live, if you remember to follow a few and simple guidelines the results will be outstanding.
____________
Best Regards,
Carl Huff

Thanks for the detailed reply Carl.

Does the AP20 not have the XO freq range to biamp subs?

you can split the sub channel any which way you can...

CINERAMAX stated it correctly. The AP20 treats all channels the same. There is no problem biamping the sub channel. The xover frequencies are not fixed. You can make them whatever you want them to be.

____________
Best Regards,
Carl Huff

Carl, will the new bass management be separate from the current Dirac Live , requiring different measurments? Or will it be one and the same , just offering more versatility down in the lower frequencies?

David,

Bass management will be added to the AP20 firmware. The Dirac Live software will be the same as it is today. Bass management will take place when you are using the system and will have no affect on the Dirac Live optimization as the Dirac Live software will have already optimized the subwoofer channel using the test stimulus. In use what will happen is the low freqs from the managed channels will be summed into the sub channel. Worst case after installing the new bass management firmware you may find yourself turning down the sub channel level a bit.

_____________
Best Regards,
Carl Huff

Hello Chris,

In the Dirac manual it states that if the midrange and tweeter drivers are not time aligned Dirac will correct that.

Could you lend some insight on how that is done?

Thank you,
George

Hello Chris (again),

I have two ways to run my L/R main speakers. Each speaker has its own sub good down to 18Hz and is thus biamped.

Currently I use a Rives parametric eq for the subs and Pass Labs external crossover to set LP and HP. Both are very high quality in my opinion. Both are analog.

With the AP20 I have two options:

1) I could treat the Speaker/Sub combo as a unit and let Dirac Live run its magic. This would require Dirac Live to use less horsepower and allow it to see the Speaker/Sub as one entity.

2) Or I could use the AP20 to set the LP and HP and eliminate the Rives and Pass units from the system. This would simplify the system and perhaps give Dirac Live more control.

If 2) is the answer how do I determine the initial LP and HP to use in the AP20?

Thanks (again),
George

PS I don't use a center and have the same speakers and subs for my rear channels. For sides I use dipoles above my head in a 20x40' "great room" with the speakers 12' apart. I have dedicated LFE sub.

Wouldn't it work in a similar fashion to Audyssey--where the EQ is determined without reference to crossover settings, so you can apply them afterward as you wish as long as they are within the "flat" part of the speaker's range?

Originally Posted by GGA
"If 2) is the answer how do I determine the initial LP and HP to use in the AP20?"

Crossovers are a function of the AP20. Most people are already aware of the crossover points from using analog crossover boxes and manufacturers specifications when they install an AP20. Dirac Live stands separate and treats the pair as one channel and really doesn't care where the crossover is at or even if it is there.
___________
Best Regards,
Carl Huff

From my experience in setting up my 2-channel system there is a lot of flexibility in choosing crossover points, slopes, and distances (delays). When I was using a Tact 2.2X it offered the choice of crossover points in 1Hz increments, slopes up to 24th order, and delays of the main or sub in 1ms increments.

You could fiddle with these three parameters endlessly and change the simple frequency response at the listening position. But just looking at such a simple response is really not that helpful.

I was hoping that Dirac Live might already have some programs that would look at the multiple separate measurements of the sub and speaker and suggest parameters on how to best integrate them. I'd think the better the integration the less work Dirac Live would have to do. I think I might be in fantasy land here.

If you use the AP20 to triamp your speakers does Dirac Live time align all three drivers?

Is there any attempt to time align a subwoofer?

Well I took the plunge. There is just so many features that make this machine so tweakable and with almost unlimited flexibility with setup, it is hard to fault from what I can tell. My unit should be arriving next week. Just wanted to thank Carl for answering all my question via email. (There was quite a few)

Congrats!! Waiting on your review!!!

Way to go, Dave! The AP20 looks like a powerful tool. Did you get the subs in yet?

Dan

Thanks, looks like I will be spending a lot of time down in the basement. Considering I have a few preamps on hand that have had the calibration done, it will be interesting to switch between them and see the difference.


Thanks.
No, not yet.

I was reading through the Dirac Live manual and saw that it has apparently complete LP and HP settings. These seem to duplicate the LP and HP functions that appear in the AP20.

This goes to my original question (which I hope will be answered) on when and where to apply crossovers. If one uses the AP20 the XO will be applied to an unequed signal which will then be fine tuned by Dirac Live.

To me it is not ideal to choose your XO by using unequed signals. Let's say you decide that 80Hz and 4th order is the best XO. If there is a peak at 25Hz and you correct it this will affect the phase at an 80Hz XO point and this may no longer be the best XO point. Certainly it seems better to flatten the peak first and then start looking at the XO.

The XO in Dirac Live is applied at the same time frequency and time corrections are done. For a simple dedicated subwoofer/main speaker setup it would seem best to run Dirac Live first individually on the sub and main and then pick crossovers. Dirac Live cannot measure the results with its filters applied, so one would need an independent program to measure the results. Theoretically the XO should be a perfect sum of the LP and HP since the sub and main signals are near ideal.

Also it would seem undesirable to use the HP and LP on the same signal in both the AP20 and Dirac Live.

I hope I am not overcomplicating the matter, and this may be an example of a little knowledge is a dangerous thing.

EDIT: It seems that Dirac Live uses 1Hz increments in LP/HP while the AP20 uses 10Hz increments, a bit too coarse for HT I think.

Some of us have had pro audio based systems for years. Yes, boutique HT equipment is overpriced and generally underwhelming. Pro audio is hwere the performance is. But many feel good about buying a good 'name' in HT.

GGA and Raul, I emailed Carl with your queries and I am sure he will respond to your questions. He seems like a very busy man, but always makes time to answer any questions I have had. (I have been emailing him for a while now)

I don't want to comment on the new base management software, as I will leave that up the Carl. He would do a better job of it for sure.