Enclosure Calculations

[Ayotte]

Hi guys. I'm just bought some Pyle replacement speakers that im going to put in an old set of Peavey SP-1's. I gutted the enclosure and what I have now is a 28.5 inch height and a 22.5 inch width. The depth can be whatever I want up to 19.5 Inches. The speakers require 11.36 cubic feet of space. What I would like to know is what kind of depyh I should build into it and what size and lenght of ports I should use to optimize the performance. Here are the speaker specs.

* 250 Watts RMS/800 Watt Peak* Sensitivity (1W @ 1M): 90.2 dB* Frequency Response: 30-3 KHz* 70 oz Magnet* 2.5'' Kapton Voice Coil* Stamped Steel Basket* Strong Black Paper Cone* Cloth Edge Suspension* Bumped & Vented Pole Piece* 8 Ohms ImpedanceI tried a couple calculator downloads off the net but did'nt really get anywhere with port size.Any help would be greatly appreciatedThanksAyotte

[Pashley]

You need the Thiele-Small parameters of the speakers to calculate enclosure & port sizes. At least resonant frequency, Qts and Vas, probably others. Look for them on the spec sheet or the web, or ask the vendor.

Once you've got those, you can put then into a modeling program. Many people use the free WinISD LinearTeam, but there are several others plus some web sites where you can calculate the design online.

[j.michael droke]

Hi there: To get the T/S parameters you will need to design the box size and port, try the Pyle web site, go to "manuals" and insert your driver's (speakers) model number. If it is not available, you will be given the following address to contact, PYLE Service Center 1600 63rd Street, Brooklyn NY, 11204. Hope you will post your design, construction results and listening observations. regards, Michael

[Top Shelf]

Try 2- 4" ports 11" long should get that box to an f3 of 33hz (approx)

[Top Shelf]

Oh yeah and 11.36 is the Vas for that woofer not the recommended box vol. That woofer doesn't have much in the way of xmax nor do they list it soooo,Good luck

Jeremy

[GM]

Assuming this is a PPA15, then you want the maximum depth, sealed and well stuffed since it ideally wants a ~100 ft^3 infinite baffle.

GM

[Ayotte]

Thanks alot for all the help guys. I got some of the specs off of the pyle site so I'll get the design going and let you know how it works.

Here are the specs too just in case anyone needs them also.

Vas 11.357
Qts 0.67
Qms 2.68
Qes 0.89
Nom Imp 8
Spl 90.2FsHz 26.7

Thanks again guys
Ayotte

[j.michael droke]

Hi there Ayotte: Simulation programs also use the parameter Sd, the piston diameter, which you will need to measure for every driver you enter in a program. The driver's Sd is most often defined as the cone diameter plus half of the surround measurement. Watch your units of measurement and use a pc based conversion program to convert to the units the program uses ( sometimes a mixture metric and US-ft and inches ). ...
regards, Michael

[bjorno]

Originally Posted by j.michael droke

Hi there Ayotte: Simulation programs also use the parameter Sd, the piston diameter, which you will need to measure for every driver you enter in a program. The driver's Sd is most often defined as the cone diameter plus half of the surround measurement. Watch your units of measurement and use a pc based conversion program to convert to the units the program uses ( sometimes a mixture metric and US-ft and inches ). ...
regards, Michael

FYI,

Data can be found in my picture but might be conflicting if a real measurement is performed:

b

[pacificblue]

Loudspeaker enclosure calculating with Thiele Small parameter