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Old 10th November 2011, 06:26 AM   #1
Zero D is offline Zero D  United Kingdom
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Default My First TH design

So don't expect miracles as i know it isn't one but you gotta start somewhere ! Why that driver ? Well i happened to be looking at their catalogue right before, & it "seemed" doable based on the TH criteria thread etc.

The mash up was a one octave design from 40Hz - 80Hz & imagining for eg 12dB filters - HP @ 35Hz & LP @ 85Hz

Please feel to tear it apart, critique away, & point out etc how you might improve it, & my HR design process in general

TIA
Attached Images
File Type: gif res.gif (17.8 KB, 248 views)
File Type: gif spl.gif (17.9 KB, 243 views)
File Type: gif xmax.gif (16.4 KB, 241 views)
File Type: gif input par.gif (10.6 KB, 240 views)
File Type: gif schem.gif (9.9 KB, 238 views)
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Old 10th November 2011, 12:54 PM   #2
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Something doesn't seem right there...135db @ 28hz or so from a single cabinet?
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Old 10th November 2011, 01:53 PM   #3
tb46 is offline tb46  United States
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Hi Zero D,

You might want to check your T/S parameters against the current factory values. Also, when in the Edit mode you can double click on Sd, and you'll get to a pop-up window with the driver T/S values. That way you can check for entry errors. I usually input factory values, but use Hornresp to recalculate, i.e.: enter Sd, then double click on Cms, etc.

By setting Ang to 0.5 x Pi you'll get a possibly unrealistically high output. For comparison I like to use 2.0 x Pi. I also like to use Eg=2.83 for comparison purposes.

When using the Wizard start by setting S2 and S4 to Auto (double-click the red labels), then use the sliders to get you in the ball park. Once you have something that looks reasonable you can set them back to manual.

I'll attach a Hornresp export file w/ your choosen driver (using recalculated factory T/S) in which I added a throat chamber, and used a short L12. Just something to play with.
Attached Files
File Type: txt fane_001.txt (474 Bytes, 18 views)
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Last edited by tb46; 10th November 2011 at 01:55 PM.
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Old 10th November 2011, 03:04 PM   #4
bjorno is offline bjorno  Sweden
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FYI,

IMO, Its in order too,to show an T-TQWT as topologically similar but this one when placed close to a room corner should be restricted to play SPL below ~122 dB as using high compression ratios(air velocity below 30 m/S) :

b
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File Type: jpg FaneColossus181500_T-TQWT.JPG (299.3 KB, 47 views)
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Old 10th November 2011, 05:36 PM   #5
Zero D is offline Zero D  United Kingdom
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@ m R g S r

Yes somethings wrong

@ tb46

Hi, thanks Very much for doing that for me, & the useful info you provided too. I appreciate it as it All helps I'm going to spend some time experimenting with it, & then post back

@ bjorno

Hi, thanks for the info & screenie Looks interesting.
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Old 10th November 2011, 09:50 PM   #6
Zero D is offline Zero D  United Kingdom
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Question 1/2/3 etc

@ tb46

Had a bit more time to play I wonder if you're seeing what i'm seeing ? I havn't altered Anything you inputted etc as yet.

1 - The displacement is 50% better @ 1 pi =

2 - The max power "seems" severely limited for a 1500w 12.7 Xmax driver ?

3 - The response gets lumpy at anything over 0W ?

I fully appreciate that you did this as a test for me & it isn't a production finished etc design. But to try & gain a deeper insight into using HR, i'd like to know your thoughts on the above.

TIA
Attached Images
File Type: gif disp 1pi.gif (15.1 KB, 38 views)
File Type: gif disp 2pi.gif (15.5 KB, 20 views)
File Type: gif res 1pi.gif (17.1 KB, 22 views)
File Type: gif res 2pi.gif (16.9 KB, 24 views)
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Old 11th November 2011, 12:04 AM   #7
tb46 is offline tb46  United States
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Hi Zero D,

You found some interesting graphs that I normally don't use, and you may want to ask David McBean about them. I'm assuming, that when Pmax is engaged the program calculates against this value, the "lumpy" response looks that way as at constant power the SPL response becomes a function of the impedance. When Eg is held constant (this means the applied power varies inversely to the impedance), the SPL response smoothens out. Sliding Xmax to 0.0 causes the graph to display the default response that you get when you hit Calculate in the Input screen.

For displacement I look at the Diaphragm Displacement window (after clicking on Calculate) after setting the input power under Eg (double-click Eg).

For limits I look at the Maximum SPL Tool from the SPL Response window. E.g.: set Maximum driver input power in watts to: 1500, and Maximum diaphragm displacement in mm to: 12.5.

Regards,
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Old 11th November 2011, 12:50 AM   #8
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Hi there ZeroD: TH's are severly limited at "low" frequency by Xmax. So manually set Eg to a value... try 28v, then go to displacement screen and examine the graph. If dispacement is still below 12.7mm, return to input screen and edit Eg to a higher value...etc...untill you reach Xmax, from the displacement graph, you can see the frequency where you will need to CUT OFF the low frequency to get more driver power without exceeding Xmax. If you really want to reach flat to 28hz low corner (F3 probably 22/23hz), you probably need to revise the input selections or redesign completely. HR can do a fine job, but it usually takes some time to get to your design limits: low corner,
F3, power needed, Xmax available, band width desirable, size/weight you can tolerate, driver(s) cost. ...regards, Michael
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Old 11th November 2011, 12:37 PM   #9
Xoc1 is offline Xoc1  United Kingdom
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Default Physical size?

These TH sims seem quite small at 220 Litres (Zero D) and 189 Litres (Bjorno)
So small in fact that I could see there could be difficulty in fitting a 18" driver.
Dimensions of the Fane Driver are 45.7 cm across flats and 22.5 cm deep
45.7 X 22.5 = 1028.25 cm sq - The cross sectional areas in the sims are far smaller than this value.
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Old 11th November 2011, 06:00 PM   #10
bjorno is offline bjorno  Sweden
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Quote:
Originally Posted by Xoc1 View Post
These TH sims seem quite small at 220 Litres (Zero D) and 189 Litres (Bjorno)
So small in fact that I could see there could be difficulty in fitting a 18" driver.
Dimensions of the Fane Driver are 45.7 cm across flats and 22.5 cm deep
45.7 X 22.5 = 1028.25 cm sq - The cross sectional areas in the sims are far smaller than this value.
Agree There's a short of required CSA but this can easily be fixed when in a single fold: Double or triple the thickness(0.75"= ~19 mm) of the internal divider.

b
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