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Multi-Way Conventional loudspeakers with crossovers

Refurbishing PSB Image 6Ts - sanity check!
Refurbishing PSB Image 6Ts - sanity check!
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Old 15th February 2019, 06:44 AM   #11
wintermute is offline wintermute  Australia
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Refurbishing PSB Image 6Ts - sanity check!
Hi Don, there was a spec tab on the jaycar site, should have enough for a sim... Hasn't got Sd, but since that will only affect output level a guestimate for a 6.5" driver eg your 134.8cm for the dayton 160 should do the trick

Speaker Type Woofer/Midrange Resonant Frequency 49.5Hz Driver Material Coated Paper Nominal Impedance 8Ω RMS Power Rating 60W Mounting Hole Diameter (B) 168mm Frequency Response 44Hz-7kHz Sensitivity (SPL@1W, 1m) 89dB Driver Channels Single Driver Side-to-Side Diameter (A) 178mm Recommended Speaker Box Volume 19l Cutout Diameter (C) 145mm Insert Depth (D) 77mm Mechanical Q (Qms) 2.02 Electrical Q Factor (Qes) 0.57 Total Q (Qts) 0.44 Equivalent Volume (Vas) 19l DC Coil Resistance (Re) 6Ω
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Old 15th February 2019, 10:24 AM   #12
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Refurbishing PSB Image 6Ts - sanity check!
hmmm that formated badly!!
fs 49.5hz
qms 2.02
qes 0.57
vas 19L
re 6 ohms

no le either but again could just put in an estimate, will affect higher frequency rolloff in sim..

Tony.
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Old 15th February 2019, 12:57 PM   #13
DonVK is offline DonVK  Canada
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I think you're right.

I was going to fill in the blanks but when I noticed there was no detail on the motor (Bl, Le) and nothing on compliance (Cms) I bailed and just used another driver which I already had info on.

I'm waiting for Cori to inspect the chambers to confirm what the actual volume and configuration is. Then I'll (or he can) rerun HornResp to see what can be changed to tune it. The bigger problem is going to be fixing the low impedance.

Last edited by DonVK; 15th February 2019 at 12:57 PM. Reason: typo
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Old 15th February 2019, 01:40 PM   #14
DonVK is offline DonVK  Canada
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Just noticed I forgot a pic that may help.

The PCB tracking photo (post#8 ) is a bottom view and to make it easier to figure out the connections we need a top view to overlay the components. So this is the "mirror" and "rotated" view. It's like an x-ray view of bottom tracking as viewed from the top side. It aligns to the component orientations in post #9.
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File Type: jpg XO tracking top view.jpg (95.1 KB, 79 views)
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Old 17th February 2019, 08:12 AM   #15
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Refurbishing PSB Image 6Ts - sanity check!
I've never used hornresp so not sure how many factors it takes into account, the modeling programs I have used generally calculate the missing params from the qms, qes, fs, VAS and re I think

Tony.
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Old 3rd March 2019, 09:29 PM   #16
Francop23 is offline Francop23  United States
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Default psb 6t

I have the original Image 6t. psb listed them as 3 1/2 way floor standing speakers. They were the top of the Image line which was below the Stratus line.
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Old 3rd April 2019, 11:55 AM   #17
Cori is offline Cori  Australia
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Hi all (and especially Don and Tony)

First up, sorry for my long absence. My work sometimes takes me away for months with very little notice! I'm back and I'm keen to complete this project. I'm hoping I haven't worn out my welcome with my absence.

Measurements
I've taken the internal dimensions of the cabinet, which has three sections (the top one containing the tweeter, driver and port):
Click the image to open in full size.

Ports
The cabinet has three ports. Each port is 20cm in length, with 2" internal diameter (each port says 'schedule 40 PVC 2"' on the side).

Wiring
From top to bottom:

Tweeter: blue, yellow
Top driver: black, red
Middle driver: black, orange
Bottom driver: black, dark green

I hope this information is what's needed!

My deepest thanks and gratitude for all your help so far.
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Old 3rd April 2019, 04:45 PM   #18
DonVK is offline DonVK  Canada
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Welcome back Cori

There are no time limits here. Some of these threads have run on for years.

The wiring colours you traced out agree with the XO schematic I posted earlier, which is good. I'll post some bass tuning info (HornResp) using the dimensions you provided and the drivers you have. Probably later tonight.
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Old 5th April 2019, 08:24 PM   #19
DonVK is offline DonVK  Canada
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Default Baffle step loss

Hi Cori,

There will be a low freq loss due to the narrow baffle. Some of the pressure will peel back around the edges but most will go forward. There is a baffle step loss calculator from Jeff Bagby and we can calculate the loss for each woofer based on the driver size, location and cabinet. The calculator produces an FRD files that XSIM can use. Notice in the XO design (earlier post) the bass was raised several dB and it will compensate for this effect.

I've shown the calculator screen shot
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File Type: jpg BagbyBaffleCalcImage6T.jpg (309.4 KB, 37 views)
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Old 5th April 2019, 08:41 PM   #20
DonVK is offline DonVK  Canada
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Default Box Tuning

Based on the dimensions and the tuning ports, there are slightly different tunings for each chamber.

I've used the Jaycar CW2194. The spec sheet is missing a few parameters so I needed to guess at the motor inductance (Le) and strength (Bl). A weaker 6.5" woofer has Bl=6, and stronger one has Bl=10. I should say that from the speaker spec and design, it tuning favours a weaker motor (lower Bl). I've put the responses for the 3 chambers below. The current tuning looks OK, no need for saws

Next - putting all the info into XSIM

Cori, were you planning on running them as BiAmp or single amp. There is still the issue of low impedance.
Attached Images
File Type: jpg HornRespImage6T_JaycarCW2194.jpg (86.1 KB, 34 views)
File Type: jpg HornRespImage6T_BottomWoofer.jpg (68.5 KB, 34 views)
File Type: jpg HornRespImage6T_MiddleWoofer.jpg (68.7 KB, 6 views)
File Type: jpg HornRespImage6T_TopWoofer.jpg (68.9 KB, 5 views)

Last edited by DonVK; 5th April 2019 at 08:42 PM. Reason: typo
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