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DIY Audio Nirvana 12" + Dayton Reference FAST project

ppataki

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I am sharing with you yet another DIY project we have done with my neighbor (who is a carpenter...:)) much earlier this year
It is a FAST (Fullrange Assisted Subwoofer Technology) system consisting of 12" Audio Nirvana Classic fullrange speakers and Dayton Audio RSS315HF-4 subs

I could not find the pictures about the construction but here are the final results in my living room:

1630823740071.png


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Both cabinets are sealed, the fullrange is 70 liters with a Qtc=0.69, the sub box is 27 liters with the same Qtc
The fullrange cabinet is made of 18mm MDF whereas the sub is made of 30mm plywood (they were not made at the same time, hence the difference, I know it is not ideal) - nowadays I stick to plywood and ditched MDF
The interior walls are covered with polyester fiber (https://www.soundimports.eu/en/monacor-mdm-2.html), except for the front wall
All the speakers are driven by Hypex Ncore NC250MP amps and an Okto DAC8 Pro DAC

Now let's see the measurements!
All these were done with REW using UMIK-1 microphone at listening position. Optimizations were done using Dirac Live 3 and Pultec EQ (by Waves).
Crossover is at 80Hz 24dB/octave using Acon Equalize 2 in Mixed Phase mode
The presence or lack of tilt at both end of the spectrum represents my own taste/preference, they can be freely adjusted

Frequency response (1/12) with Excess Phase, dips are room-related
My room dimensions are 720*360*260 cm so very nasty room modes are present unfortunately
As you can see in the pictures the only treatment is the two bass traps in the front corners (HOFA Natural)

1630824922420.png


Impulse response:
1630825025832.png


Step Response:
1630825090257.png


Excess Group Delay:
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Waterfall
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Wavelet
1630825341728.png


And for those who like the horror genre, the FR pre vs post correction:
1630825453828.png


Some subjective comments: this is by far the best system I have ever had in my life (so far). I previously had many 2-way and 3.5-way systems (mainly Nuberts, like the nuBox 513 and then the nuVero 140) but this beats the crap out of those. Dynamics are insane and the "live sound experience" that fullrange systems provide is totally there (I guess that is due to the fact that there is no crossover in the 300-3000Hz region). I can 'see' the musicians in the room.

The biggest 'drawback' is that this is a one-man system, if I move my head just a few centimeters away from the sweet spot the sound is no longer the same - this is due to the extreme beaming of the fullrange drivers - but I really don't mind; I was aware of this before I ventured into the realm of fullrange drivers

The bad news is that the whole system will be decommissioned and replaced by this one: https://www.audiosciencereview.com/...-corner-line-array-project.25983/#post-887939 due to the pressure from a Higher Power (=my wife)
She needs more space in the living room hence I 'decided' to give a chance to Murphy's Corner Line Array
More on that later in the above post in a few months' time

I hope you find this useful, any comments/questions are welcome
 

Grotti

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Thank you very much for your post and the beautiful pictures. I have some sympathy for your wife since it always is a struggle to integrate speakers and electronics in the living environment: your pictures are proof ;).

Since you pointed out, that the subjectively great performance could be partially due to the fact, that there is only one driver reproducing the range from 300 to 3000 Hz without a crossover: have you ever thought about a smaller broadband speaker assisted by a low coupled bass and a high crossover point to a tweeter? This could solve the problem of a small sweet spot to some degree without loosing much of the dynamics.
In former days I enjoyed a Triangle Magellan Cello very much (subjectively!) which seems to follow this design rules.

Nevertheless I look very much forward to your thread on the corner speakers!
 
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ppataki

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Thank you! :)

No, I did not want to do that since I really don't mind the small sweet spot, plus I never wanted to introduce yet another crossover in the system (the fewer the better - in fact the corner line array project will be a true one-way system, am very curious to see that....)
What I tried though is crossing the sub at higher frequencies such as 100Hz, 150Hz, 200Hz
The results were somewhat poorer compared to crossing over at 80Hz; it was most prominently visible in the Wavelet diagram
The 100Hz-ish domain got 'dirtier' in the diagram meaning that the Impulse Response got worse
I guess that means that the Dayton is not to be used in higher frequencies and I have a gutt feel that this might be true to other subwoofer drivers too.
Not to mention that when crossed over at a higher frequency the male vocals were clearly audible from the subs too which I guess is to be avoided
 

Grotti

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Thank you! :)

No, I did not want to do that since I really don't mind the small sweet spot, plus I never wanted to introduce yet another crossover in the system (the fewer the better - in fact the corner line array project will be a true one-way system, am very curious to see that....)
What I tried though is crossing the sub at higher frequencies such as 100Hz, 150Hz, 200Hz
The results were somewhat poorer compared to crossing over at 80Hz; it was most prominently visible in the Wavelet diagram
The 100Hz-ish domain got 'dirtier' in the diagram meaning that the Impulse Response got worse
I guess that means that the Dayton is not to be used in higher frequencies and I have a gutt feel that this might be true to other subwoofer drivers too.
Not to mention that when crossed over at a higher frequency the male vocals were clearly audible from the subs too which I guess is to be avoided
I think it's a question of the implementation. I don't hear many members here complain about the mids of the Neumann 310, where the bass driver is coupled at 300 and a few Hz (IIRC) to the mid dome. In case of the Magellan the two 7" bass drivers handed over to a single midrange driver (in fact a broadband speaker) about 400 Hz. Worked fine and flawless to my ears. Perhaps the point is to use smaller units to integrate well.
 

DavidMcRoy

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Ppataki, I've been binge-reading your posts about your full-range driver projects tonight, because I had decided to try one of my own and was looking around for inspiration. I'm using a KEF Q150 Uni-Q as a center channel speaker in a Dolby Atmos system, flanked by Acoustat Spectra 1100 electrostatics. I've dialed-in really good sound, but for giggles I want to play with a MarkAudio Alpair 12P 8-inch full-range driver in open baffle configuration. I have an idea about backwave control based on what I've learned experimenting with planar speakers over the years, applied to conventional cone drivers. I'll post results when I lash everything together. Thanks for pioneering!
79AE9543-7E0D-472F-A1B1-05169286EC04.jpeg
 
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ppataki

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I am happy to hear that @DavidMcRoy!
Whatever you do, just make sure to use heavy DSP for correction - that is a must-have for these kind of drivers
I had tried the Alpair 12p in the past, it has a nice sound when corrected but be aware that it is not very much loadable in terms of power (its xmax is limited) - hence I switched to the CHR120
 

DavidMcRoy

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I am happy to hear that @DavidMcRoy!
Whatever you do, just make sure to use heavy DSP for correction - that is a must-have for these kind of drivers
I had tried the Alpair 12p in the past, it has a nice sound when corrected but be aware that it is not very much loadable in terms of power (its xmax is limited) - hence I switched to the CHR120
I use DSP extensively on everything. I've been experimenting with 12dB slopes from 80Hz and 6dB slopes up to 320Hz for the Q150. (The Acoustat panels have a passive 250Hz cutoff at 12dB built-in.)
 

dualazmak

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Some subjective comments: this is by far the best system I have ever had in my life (so far).

I regret and I am so sorry that I noticed this your wonderful thread just now; I have jumped to here from your post here!

I feel exactly the same with my almost completed DSP-based multichannel multi-SP-driver multi-amplifier fully active stereo audio setup (ref. here for the latest system setup).

I can easily guess how wonderful was your system for "music listening" in your room acoustics.

Rather fortunately in my setup, I have good "listening position margins" about within one meter (100 cm) left-right, front-rear, up-down, from the center head position on the listening sofa, which is more than enough for enjoying music with my wife.;)

Thank you gain for sharing your wonderful setup with us!
 
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ppataki

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Thank you @dualazmak for your kind words, appreciate it!

FYI here are my other projects too:

 
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