SBAcoustics NAC-61 SB17NBAC35-4 and SB26ADC000-4 .FRD .ZMA sharing

anyone whom made NAC-61 can you share .frd .zma of SB17NBAC35-4 and SB26ADC000-4 please.

I try to simultation without .frd and .zma but it might not correct.
NAC-61.jpg
 
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Sorry I cannot help with the data you require as I haven't built the design.

Purely as an observation the Xovers look reasonable for 4 ohms impedance.

I guess you are talking about the Troels Gravesen SB NAC61 design, if you look at his web page for this design he has the bass down by 35 dB re the the normal response by 5Khz. maybe you could teak that?

For the tweeter, you seem to have the roll of to 1KHz correct, but you haven't achieved the knee where the attenuation rate changes at 2KHz.

When you build these can you take measurements as that will help you refine the crossover and frequency response?

Good luck with the build.
 
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Are you using "ideal / perfect / dummy" FRD and ZMA curves? or have the actual curves been overly smoothed. your frequency response should have ripples and bumps / dips in it if "Real world"

If you let me know your baffle dimensions and driver placements on the baffle, I can provide data.

Edit - I see your impedance is 8 ohms, yet you are using 4 ohm drivers, therefore dummy ZMA?
 
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Due to no .FRD .zma the impedance show in picture is 8R. If input ,frd .zma the impedance will be 4R.

The cabinet is 14.5liters Fb is 39hz F3 is 47.2Hz

I saw NAC 61 cross at 2100Hz LR4 then i try to guess all L R C value.

If anyone can share .frd .zma i think i can correct the crossover.

Thank you
 
Due to no .FRD .zma the impedance show in picture is 8R. If input ,frd .zma the impedance will be 4R.

The cabinet is 14.5liters Fb is 39hz F3 is 47.2Hz

I saw NAC 61 cross at 2100Hz LR4 then i try to guess all L R C value.

If anyone can share .frd .zma i think i can correct the crossover.

Thank you
I need the baffle dimensions and driver placement please.

I can explain why, bit it would take too long. Just trust me
 
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Here is why I want to know your baffle dimensions and driver placement.
The blue curve is what the manufacturer provides for the SB17NBAC. The green is what happens with baffle step and edge diffraction when you place it in on a smaller baffle than the manufacturer measures on. You want to model your crossover using the green curve, and your curve will be different than the green curve shown, because your baffle will be a different size but also because your SB17NBAC is in a ported enclosure (the green curve shown is from a sealed box)

1694387733121.png
 
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I'll upload files soon, but want to post a few images so you can understand what is happening:
The White line is your target SB26ADC response in your cabinet.
The pink line is the original SB Acoustics manufacturer response on an IEC baffle.
The blue response is the IEC baffle
the green response is the baffle step and diffraction of your cabinet.

When we take pink - minus blue and add green - then you get your white (target) response).

I'll post the SB17NBAC next, then FRD/ZMA that you want

1694395495961.png
 
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Here's your SB17NBAC35-4 response:

The WHITE is your target response.

the CYAN (light blue) is the infinite baffle "box response" that SB Acoustics bases their woofer frequency extension on

The PINK is the SB Acoustics factory measurement

The YELLOW is your predicted vented box response

The BLUE is the IEC baffle response for 6" driver measurements

The GREEN is your in box woofer response, with MIC on tweeter axis (at nominal 1m design distance).

1694396059553.png
 
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Oh !! This is superb simulation software + expert Mr. Dave. I am so gratitude to you for spending time simulstion for me. Due to my humble knowledge, could I please ask for more to revised my crossover to make it more linear.

I hope you can spare your time revise crossover schematic. I will attach crossover file in this thread.

From graph range 700-2000 is too high need to be adjust to make vocal less forward b/c I sit near speakers in small bedroom 4x3meters

Thank you very very much Mr. Dave
 
Attached are the files I've used. The impedance is from the SB17NAC (white cone) version but identical to the NBAC version. (My NBAC version impedance was corrupt. I do have an SB17NBAC35-4 on hand but its packed away so won't measure). the NAC impedance does not show the vented box "double hump" because that does not matter / affect crossover design (i.e. raw manufacturer impedance can be used). I can splice in the box impedance if needed, but it won't affect the crossover
 

Attachments

  • SB17NBAC in box on axis.frd
    31.6 KB · Views: 53
  • SB26ADC in box on axis.frd
    31.7 KB · Views: 43
  • SB26ADC.zma
    11.1 KB · Views: 52
  • 6_ SB17NAC35-4_ZR.zma
    15.8 KB · Views: 49
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How to decrease high bump between 600- 2200 hz about 3db. for the decrease frequency in 3000 - 4000 hz I will adjust with EQ of Jriver Media player.

I think revised crossover can lower the bump of range 600-2200hz to be better. I try to simulate and need more time. Now I just post my revised file

Sadly the crossover point drop quite low to 1900Hz instead of 2100Hz as photo.


NAC-61_4.jpg


.dbo file here
https://file.io/EG6CuxurAL1B