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Help modelling giant twin 18'' reflex

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Noyzmunky View Drop Down
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    Posted: 13 March 2020 at 6:59pm
Hey Guys, I have a pair of peavey low rider 18'' drivers. They are as new. The cabs they are in are peavey UL118s and they are a bit weak. Stapled together, minimal bracing and wadding. etc.

I have been informed by reading Elliott's old posts on the subject that they like to be in massive cabs 400l or so.. The Peavey site says it's large vented box is 255 and they are currently in around 270l cabs. Lots of variance there.

Can someone have a look at the TS and tell me how many litres these would like in a vented reflex to really play out to 30hz (like the stats say they can)?

Many thanks for any assistance, I have never used a modelling program so which one is good for reflex please?. This would be my first built cab and I fancy letting the drivers have what they want in cab space and just have it as an install piece in my container.

t/s p

Net weight lb. / kg:22 / 10
Znom(Ohms) 8
Revc (Ohms) 6.21
Sd (Square Meters)0.1237
BL(T/M) 22.73
Fo (Hz) 28.9
Vas (liters) 403.9
Cms (uM/N) 185.9
Mms (gm) 163.2
Qms 8.770
Qes .356
Qts .342
Xmax (mm) 9.6
Le (mH) .87
SPL(1W1m) 97.3
no (%) 2.65
Vd cubic inches / milliliters145 / 2375
Pmax (Watts pgm.)1600
Disp (inches3) / milliliters235 / 3852

I believe these are the stats for the older version, and I believe they are the ones I have.

Cheers for any help and pointers for a noob to designing.
my name is Inigo Montoya...you killed my father, prepare to die!.
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Noyzmunky View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Noyzmunky Quote  Post ReplyReply Direct Link To This Post Posted: 13 March 2020 at 7:00pm
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MattStolton View Drop Down
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Post Options Post Options   Thanks (1) Thanks(1)   Quote MattStolton Quote  Post ReplyReply Direct Link To This Post Posted: 14 March 2020 at 11:41am
For reflex boxes, WinISD is as good as many:

http://www.linearteam.org/

Red line is PV recommended box 255L, Tuned to 30Hz.

Green is an auto generated "optimum" 508L, tuned to 24.5Hz



Always pinch of salt, but gives you an idea.

Remember when entering T/S Params:

Originally posted by linearteam help page linearteam help page wrote:

The suggested procedure for entering driver parameters is following (check first that "Auto calculate unknowns" option is checked):
1. Enter Mms and Cms
This gives fs. If either is not available, then enter fs and other parameter.
2. Enter Sd, Bl and Re
Now, you should get all but Qms (and Qts), Vas. Please note that Vas may not match exactly what is specified by manufacturer, because exact value of Vas depends on environmental parameters. See FAQ.
3. Enter Rms or Qms.
Either one will do, although I tend to prefer Qms over Rms, because it can usually be measured in driver measurement procedures.
4. Enter Hc, Hg and Pe.
If Hc or Hg or either is available, then enter Xmax and optionally either Hc or Hg if available.
5. Enter number of voicecoils.
This procedure is most accurate. Also note that it also calculates true SPL (1W/1m) value. So it might not match the marketing SPL value, which is generally somewhat vague. Not in all cases, though.
6. Correct Znom, if necessary.
If there are several voicecoils, then you must be careful when entering parameters in that case, because many manufacturers give Bl in voice coils in series, because it yields double value for Bl against parallel connection. If driver manufacturer gives Qes, Bl and Cms or Mms, then you can check how Bl is specified. For that, you can enter following parameters to calculate Re: Qes, Fs, Mms or Cms and Bl. Connection mode can be changed by changing the combobox selection. The driver editor then converts Bl and Re values accordingly.
Equivalently, you can check for Bl by entering:
Qes, Fs, Mms or Cms and Re (for desired connection mode).
If you enter resistance for parallel connection and get about half of advertised Bl, then you know, that Bl was specified that way.
Like in Driver-tab in project window, you'll probably noticed the driver icon in bottom of the driver editor window. you can drag the driver object into some project by just dragging the icon.
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Elliot Thompson View Drop Down
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Post Options Post Options   Thanks (1) Thanks(1)   Quote Elliot Thompson Quote  Post ReplyReply Direct Link To This Post Posted: 14 March 2020 at 12:15pm

When I design my boxes, my objective is to attain the lowest/flattest frequency response the driver can accomplish before a gradual roll-off due to the design limitation of the loudspeaker from a frequency response perspective.

 

When Peavey recommends a design for their loudspeakers, they compromise low frequency extension for a more compact enclosure since, the majority of their customers do not like large boxes.

 

You really need to start to learn how to scale your own designs using a loudspeaker design software.

 

I used to use WinISD around 20 years ago before buying Eminence Designer.

 

By you learning how to scale a box in a Loudspeaker Simulator, it will allow you to make your own compromises based on your requirements than, settling on what some one else or manufacture feel is best under the given conditions.

 

Best Regards,



Edited by Elliot Thompson - 14 March 2020 at 12:18pm
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Noyzmunky View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Noyzmunky Quote  Post ReplyReply Direct Link To This Post Posted: 14 March 2020 at 3:57pm
Ah that's amazing cheers guys. I will way to the data banks and see what I can come up with.. That really points me in the right direction.

I like the idea of a 1000 liter twin 18'' to stack everything else on for gatherings, Like maybe the buffet and a suckling pig

my name is Inigo Montoya...you killed my father, prepare to die!.
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gen0me View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote gen0me Quote  Post ReplyReply Direct Link To This Post Posted: 14 March 2020 at 5:31pm
I though for a sec you meant 508l for two drivers, was wondering why my charts dont match :) Here is graph for 2 in one box. Althought after changing 9.6math xmax into ~12mm you still have some room for bigger cab from this chart...


Edited by gen0me - 14 March 2020 at 5:40pm
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Post Options Post Options   Thanks (0) Thanks(0)   Quote gen0me Quote  Post ReplyReply Direct Link To This Post Posted: 14 March 2020 at 6:23pm
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