Doh! Attach image, not attach file! Here are some of my measurements
1. Sub pre-amp output (before low pass filter), "flat" and boost switch positions. 2. Same measurement after modifications. 3. Sub amp output at various low pass settings, stock unit. 4 ohm load 4. Same measurement after modifications. 5. Satellite frequency response, stock fixed highpass filter F3 = 85 Hz, no mods made. 6. Satellite THD at various power levels, 4 ohm load. Lowest trace is my loopback test. My test setup is limited to measuring 20W.
If you find your notes and are willing to share, please let us know. I'll probably order two of those plate amps. They, along with your modifications, look perfect for a couple projects I have in mind.
Today the Peerless TC10FG00-04 is on sale https://www.parts-express.com/peerless-by-tymphany-tc10fg00-04-4-full-range-line-array-driver-4-ohm--264-1360 What I noticed about this driver and most of the Peerless TC series with cloth surround is the 2-3dB increase in sensitivity but also the rough mid-band frequency response. The roughness in the response seems to be due to the surround non linearity and lack of damping. The rubber surround drivers in the TC series have smoother response and lower FS & Sensitivity. I think the cloth surround is lighter weight and that improves the efficiency and raises the FS of the driver. What would be nice is if there was some type of surround that could be light weight and more linear like the rubber surrounds. Having a driver with higher efficiency reduces the power compression because it takes less power to produce the output level.
Today the Peerless TC10FG00-04 is on sale https://www.parts-express.com/peerless-by-tymphany-tc10fg00-04-4-full-range-line-array-driver-4-ohm--264-1360 What I noticed about this driver and most of the Peerless TC series with cloth surround is the 2-3dB increase in sensitivity but also the rough mid-band frequency response. The roughness in the response seems to be due to the surround non linearity and lack of damping. The rubber surround drivers in the TC series have smoother response and lower FS & Sensitivity. I think the cloth surround is lighter weight and that improves the efficiency and raises the FS of the driver. What would be nice is if there was some type of surround that could be light weight and more linear like the rubber surrounds. Having a driver with higher efficiency reduces the power compression because it takes less power to produce the output level.
Foam surround? Where does foam surround fall? A lot of the older drivers has foam surround which would rot over time, but modern drivers with coated foam surrounds are pretty long lasting. I have a couple of drivers with coated foam...
These have a pretty interesting set of compromises and I've been wanting to try them for a while. The quoted sensitivity jives pretty well with the calculated sensitivity, so 4 of these per side could yield a legit 98dB sensitivity speaker good down to 150-200Hz and just large enough to fit the drivers on a baffle. 35% off sounds like a good time to nab multiples.
Edit: I can't get the attachments to show up. I use the "attach file" option, select the jpeg files and the files are displayed until I post. Then they're gone. I assume I'm making some stupid error. Any help?
As 6th says above, file attachments don't work right. I'd trade my kingdom for a reason why (been debugging more hours than I care to count). However if you upload a picture through the image button above the edit box, that works fine.
= Howard Stark: "This is the key to the future. I'm limited by the technology of my time, but one day you'll figure this out."
I worked through the suggested process for unknown passive radiators as stated by Jeff Bagby in 2012, PETT PE has now updated the project page with: XMAX = 20 mm.
I ran LIMP ZMA tests with and without the added weight, ran close miked OM sweeps for Fb, and simulated various PR parameters in WBCD until I got very close to the measured results. The one anomaly I have in my data is that Qmp does not change a lot between no weight and added weight. No added weight: Fsp 16 Hz Vasp 75 liters Mmp 500 gm Qmp 15
I worked through the suggested process for unknown passive radiators as stated by Jeff Bagby in 2012, PETT
do you have a link for the process or how to go about it?
Can you take a couple of snaps of the front with/without the weight added? Do the weights go on the front or the back? Looking at the PE website, there seems to be an exposed nit or something on the front...
My doc for the process. I followed Bagby's tips. I can supply my summary pages and printouts if needed.
Jeff
Bagby PE Tech Talk 06-21-2012
There
is a relatively simple way. First measure the free air parameters of
your woofer. Then build a test box cut out for the woofer and the
passive radiator. You need to know fairly prescisely the box volume
and the Sd of the radiator. Make the box as air tight as possible so
box Ql doesn't throw off what we will do next. Then mount the driver
and the passive radiator in the box and measure the impedance. Now,
using my Woofer Box and Circuit Designer program you can come pretty
closee to backing out the parameters for the PR by entering the
measured free air parameters for the woofer, the know box parameters,
and the Sd for the passive. Then begin to dial in the Qmp and Mmp
until you begin to match the tuning frequency, spacing, and height of
the peaks in the measured system impedance. When you get them to
match up well you will be very close on both Qmp and moving mass.
But Chahly - Stahkist don't want speakers that look good, Stahkist wants speakers that sound good!
Weights attach to the front. Included 575 gm weight is monolith - one piece. Cone looks crappy in my pictures, but is actually very attractive waffle pattern on the front.
But Chahly - Stahkist don't want speakers that look good, Stahkist wants speakers that sound good!
Are you planning to use different weights or go with this one?
Honestly, I don't have a firm project in mind - I've recently bought on sale the Vifa NE315 12 inch, an Ultimax 15 and Dayton's PN395. Could be used with any of them. With the included 575 gm weight, it tunes super low, and that can really take the stress off of a ported woofer below Fb. IIRC, the PR sims I played with show, for example, a woofer in a ported box has an Fb about 40, and exceeds xmax around 35 Hz. Using a PR tuned real low extends the xmax exceeded frequency to maybe 27 Hz or so, but I've simmed that alignment a couple of times. Have to run the sims when I get there next year. Got a couple of projects ahead of those - shelves are full of drivers I need to use! Hope this helps, Don
But Chahly - Stahkist don't want speakers that look good, Stahkist wants speakers that sound good!
To those interested in my mods to the PE MCA2250E 2.1
amplifier: The unit is currently loaned
out so I can't take a picture, so I've attached my chicken scratching version
of the schematic. The components are positioned to match the
board layout. If someone buys a unit and
uploads a picture I'd be happy to circle the components for clarity. Until then:
The chip (TL074C quad op-amp) is located in the upper left
corner of the board.
Capacitors C1 through C6 (circled in blue, my numbering) are
all 100 nF. I replaced them with equivalent
X8R versions to reduce harmonic distortion. Replacing these made a large improvement in
the subwoofer THD.
The four resistor changes are circled in green. The resistor marked "MT" (300K) is
removed and not replaced. The others are
150K replaced with 75K, 18K replaced with 47K and 15K replaced with 36K.
The schematic shows the frequency control pot which is
obviously off board. The boost switch
connections are shown on the far left of the schematic.
I created a public cart at Digikey (Link). It has ten of each component, feel free to
change that as you see fit.
Comments
1. Sub pre-amp output (before low pass filter), "flat" and boost switch positions.
2. Same measurement after modifications.
3. Sub amp output at various low pass settings, stock unit. 4 ohm load
4. Same measurement after modifications.
5. Satellite frequency response, stock fixed highpass filter F3 = 85 Hz, no mods made.
6. Satellite THD at various power levels, 4 ohm load. Lowest trace is my loopback test. My test setup is limited to measuring 20W.
https://www.parts-express.com/peerless-by-tymphany-tc10fg00-04-4-full-range-line-array-driver-4-ohm--264-1360
What I noticed about this driver and most of the Peerless TC series with cloth surround is the 2-3dB increase in sensitivity but also the rough mid-band frequency response. The roughness in the response seems to be due to the surround non linearity and lack of damping. The rubber surround drivers in the TC series have smoother response and lower FS & Sensitivity. I think the cloth surround is lighter weight and that improves the efficiency and raises the FS of the driver. What would be nice is if there was some type of surround that could be light weight and more linear like the rubber surrounds. Having a driver with higher efficiency reduces the power compression because it takes less power to produce the output level.
Dan
PE has now updated the project page with:
XMAX = 20 mm.
I ran LIMP ZMA tests with and without the added weight, ran close miked OM sweeps for Fb, and simulated various PR parameters in WBCD until I got very close to the measured results. The one anomaly I have in my data is that Qmp does not change a lot between no weight and added weight.
No added weight:
Fsp 16 Hz
Vasp 75 liters
Mmp 500 gm
Qmp 15
575 gm added weight:
Fsp 10.5
Vasp 75 liters
Mmp 1075 gm
Qmp 15.2
Results should be close enough for design purposes. At $21 qty 4, it's a pretty great deal, IMHO.
Don
do you have a link for the process or how to go about it?
Can you take a couple of snaps of the front with/without the weight added? Do the weights go on the front or the back? Looking at the PE website, there seems to be an exposed nit or something on the front...
Regards
Ani
I can supply my summary pages and printouts if needed.
Jeff Bagby PE Tech Talk 06-21-2012
There is a relatively simple way. First measure the free air parameters of your woofer. Then build a test box cut out for the woofer and the passive radiator. You need to know fairly prescisely the box volume and the Sd of the radiator. Make the box as air tight as possible so box Ql doesn't throw off what we will do next. Then mount the driver and the passive radiator in the box and measure the impedance. Now, using my Woofer Box and Circuit Designer program you can come pretty closee to backing out the parameters for the PR by entering the measured free air parameters for the woofer, the know box parameters, and the Sd for the passive. Then begin to dial in the Qmp and Mmp until you begin to match the tuning frequency, spacing, and height of the peaks in the measured system impedance. When you get them to match up well you will be very close on both Qmp and moving mass.
Are you planning to use different weights or go with this one?
Hope this helps,
Don
To those interested in my mods to the PE MCA2250E 2.1 amplifier: The unit is currently loaned out so I can't take a picture, so I've attached my chicken scratching version of the schematic. The components are positioned to match the board layout. If someone buys a unit and uploads a picture I'd be happy to circle the components for clarity. Until then:
The chip (TL074C quad op-amp) is located in the upper left corner of the board.
Capacitors C1 through C6 (circled in blue, my numbering) are all 100 nF. I replaced them with equivalent X8R versions to reduce harmonic distortion. Replacing these made a large improvement in the subwoofer THD.
The four resistor changes are circled in green. The resistor marked "MT" (300K) is removed and not replaced. The others are 150K replaced with 75K, 18K replaced with 47K and 15K replaced with 36K.
The schematic shows the frequency control pot which is obviously off board. The boost switch connections are shown on the far left of the schematic.
I created a public cart at Digikey (Link). It has ten of each component, feel free to change that as you see fit.
It shows as 143 on sale at 40% off?
InDIYana Event Website
Wolfy's Photobucket
Now THATS a ribbon!