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Old 18th October 2021, 04:54 PM   #61
planet10 is offline planet10  Canada
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Markaudio New Full Range Driver Alpair 5 Gen.2
70 litres, what tuning?

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Old 18th October 2021, 08:08 PM   #62
superlian is offline superlian  Norway
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Ř11 cm x 17cm port

I think 40 Hz?

Outside dimension 800 x 450 x 310 mm

Last edited by superlian; 18th October 2021 at 08:16 PM.
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Old 19th October 2021, 01:24 AM   #63
planet10 is offline planet10  Canada
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Markaudio New Full Range Driver Alpair 5 Gen.2
Yes, working backwards from the vent size, 40 Hz.

Not pretty IMO. Other curve is sealed Q=0.5

Markaudio New Full Range Driver Alpair 5 Gen.2-jbk-2206-70l-sim-png

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Old 19th October 2021, 07:15 AM   #64
superlian is offline superlian  Norway
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Maybe dsp and 4 channel amplifier is better?
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Old 19th October 2021, 07:18 AM   #65
superlian is offline superlian  Norway
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Quote:
Originally Posted by planet10 View Post
Yes, working backwards from the vent size, 40 Hz.

Not pretty IMO. Other curve is sealed Q=0.5



dave
My simulation with winisd, 70 liter & 40 Hz was like this:

Click the image to open in full size.
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Old 19th October 2021, 05:15 PM   #66
planet10 is offline planet10  Canada
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Markaudio New Full Range Driver Alpair 5 Gen.2
That is quite different.

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Old 20th October 2021, 10:01 AM   #67
Scottmoose is offline Scottmoose  United Kingdom
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I'm up to my eyeballs writing a paper, but briefly, as Dave asked me to take a look at this, I suspect we're looking at variations in the modelling basis. All the basic modellers should be running the same baseline maths, but they tend to show some shifts when you incorporate other assumptions (e.g. damping, box leakage, port frictional losses etc.) even if you adjust the coefficients to nominally the same.

Attached; this is with the published data & 0.5ohm series R added for wire loop, connection resistance. All boxes of the same Vb & Fb.

Top left & centre = a modified variation of MJK (which from long experience I know to be reliable), with the dimensions stated above adjusted for internal, and the equivalent of about Qa = 40 lagging.

Bottom = Unibox, which is usually consistent with MathCAD and I usually find consistently reliable to measured.

Top right is BassBox6pro, which has some qualities, but I tend to find sometimes shows some variation in alignment terms with the same specified nominal dimensions, tuning, damping, leakage etc. YMMV. In this case, it appears closest to the WinISD alignment indicated in the post[s] above, whereas my modified version of MJK and Unibox are closer to Dave's, although adjusting for the different graph scales, in fairness overall they aren't all that far apart.
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Old 20th October 2021, 04:04 PM   #68
superlian is offline superlian  Norway
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The idea with this tuning is to use the room gain as a «friend» in ordinary Norwegian Living rooms aka Amercian bedrooms
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