The term for this is 'backronym'
Backronym - Wikipedia
A [terrible] example of this is the PATRIOT Act in the United States. They first came up with a name (that happens to be the exact opposite of anyone who's ever actually read the Constitution) then filled in the P A T R...
Cheers,
Tal
Backronym - Wikipedia
A [terrible] example of this is the PATRIOT Act in the United States. They first came up with a name (that happens to be the exact opposite of anyone who's ever actually read the Constitution) then filled in the P A T R...
Cheers,
Tal
Squishy Daggers!
A little comment on my special short, fat implementation of this wonderful design - I've worked to improve my traffic cone daggers, having first noted some air leaking, solved with round foam weatherstripping, and also found an issue with the soft, flexible quality of the cones: they don't prevent woofer-generated cabinet pressure from directly affecting the little fullrangers. Any musical content that makes visible woofer cone movement with cause simliar movement from the fullrange cone. Eliminating the air leaking made no change to this, so I conclude that the pressure simply squeezes the dagger and its enclosed driver.
Possible ways to address this are to double-layer the traffic cones, and maybe adding a stiffening compound inbetween, or replacing the soft daggers with foam board or plywood pyramids. Not really sure how much negative impact this has sonically until a solution is tried.
These speakers have been in continuous use since I completed them several months ago, and I've found them to be very satisfying, regardless of any flaws in my implementation.
Cam
A little comment on my special short, fat implementation of this wonderful design - I've worked to improve my traffic cone daggers, having first noted some air leaking, solved with round foam weatherstripping, and also found an issue with the soft, flexible quality of the cones: they don't prevent woofer-generated cabinet pressure from directly affecting the little fullrangers. Any musical content that makes visible woofer cone movement with cause simliar movement from the fullrange cone. Eliminating the air leaking made no change to this, so I conclude that the pressure simply squeezes the dagger and its enclosed driver.
Possible ways to address this are to double-layer the traffic cones, and maybe adding a stiffening compound inbetween, or replacing the soft daggers with foam board or plywood pyramids. Not really sure how much negative impact this has sonically until a solution is tried.
These speakers have been in continuous use since I completed them several months ago, and I've found them to be very satisfying, regardless of any flaws in my implementation.
Cam
Try flashing tape. (Any aluminium backed mastic, butyl or bitumen self adhesive tape). Cover the outside of the cone in at least one layer. Another possibility is Dynamat or similar.
Thanks for the suggestions! I do have a supply of Noico sheets, which I used to partially cover one cone initially, but then discovered air leaking. Wrapping the entire exterior of a cone is slightly challenging, so I used three triangles to mostly cover it. Complete coverage will provide additional stiffening but still well short of rigid.
So I have made some positive project towards building the speaker and have received the cabinet, in flat pack form from a fellow diy-er. That's half the battle for me since I was finding it impossible to make a cad drawing and get it cut.So now I'm collecting materials.
I was planning to use a MyRef 3886 amp as all my other amps have <10w output.
What is the input impedance of the crossover circuit?
I ask this because the MyRef supply voltage needs to be chosen based on whether the load is 4 ohm or 8ohm. Perhaps I missed it somewhere? I guess just calculating the impedance at the lowest and highest audio frequency does not give the actual impedance?
I was planning to use a MyRef 3886 amp as all my other amps have <10w output.
What is the input impedance of the crossover circuit?
I ask this because the MyRef supply voltage needs to be chosen based on whether the load is 4 ohm or 8ohm. Perhaps I missed it somewhere? I guess just calculating the impedance at the lowest and highest audio frequency does not give the actual impedance?
Surajspai,
Great news that a fellow DIYer has made the cabinet in flatpack for you.
It's an 8ohm speaker impedance, and doesn't vary too far off - so a very benign load. I would recommend at least 50w, and preferably a 100w amp to fully utilize the dynamics that this speaker is capable of and to give sufficient head room. Even 50w or 75w is better than a 35w amp.
You might consider a Class D amp like TDA8954 - something like this sounds very much like a nice Class AB and with same power trafo that the LM386 uses, will have 2x to 4x the power (depending on load) since it is a BTL design that provides double the voltage output swing.
https://www.ebay.com/i/123115842737?chn=ps
or
New 420W *2 Large Power TDA8954TH AD Digital Audio Amplifier Board Dual AC 24V | eBay
But if you already have the Myref, give it a try and see how you like it.
Here was my quick test of the 8954 on the 10F FAST:
TDA8954TH - XH-M252 board - anyone?
I measured 200uV to 400uV rms of noise with input source off - that's a very decent noise figure actually. Sound had good spatial imaging and excellent bass.
Great news that a fellow DIYer has made the cabinet in flatpack for you.
It's an 8ohm speaker impedance, and doesn't vary too far off - so a very benign load. I would recommend at least 50w, and preferably a 100w amp to fully utilize the dynamics that this speaker is capable of and to give sufficient head room. Even 50w or 75w is better than a 35w amp.
You might consider a Class D amp like TDA8954 - something like this sounds very much like a nice Class AB and with same power trafo that the LM386 uses, will have 2x to 4x the power (depending on load) since it is a BTL design that provides double the voltage output swing.
https://www.ebay.com/i/123115842737?chn=ps
or
New 420W *2 Large Power TDA8954TH AD Digital Audio Amplifier Board Dual AC 24V | eBay
But if you already have the Myref, give it a try and see how you like it.
Here was my quick test of the 8954 on the 10F FAST:
TDA8954TH - XH-M252 board - anyone?
I measured 200uV to 400uV rms of noise with input source off - that's a very decent noise figure actually. Sound had good spatial imaging and excellent bass.
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Hello X,
I see here they have both models you pointed to, plus this one, that has 2 huge electrolytic caps for linear current.
Do you think it might be better?
Here's the blurb from the website:
I see here they have both models you pointed to, plus this one, that has 2 huge electrolytic caps for linear current.
Do you think it might be better?
Here's the blurb from the website:
nUse original TDA8954TH
nMain electrolytic capacitors using gold NOVER brand, capacity 10000uf / 50V , 10A, and using the above flat bridge rectifier to ensure strong support for a steady stream of power.
nThe resistor uses a five-ring metal resistor, and the main circuit uses a five-ring metal film resistor with an accuracy of ±1% to ensure a good signal-to-noise ratio.
nThe PCB adopts 1.6mm thick double-sided sheet, 2.0 oz copper thickness, and the whole process of tin-spraying ensures the good passing performance of the current. First-class PCB quality.
nThe output uses a red ring high current inductor to ensure that the sound is crisp and powerful.
nMain electrolytic capacitors using gold NOVER brand, capacity 10000uf / 50V , 10A, and using the above flat bridge rectifier to ensure strong support for a steady stream of power.
nThe resistor uses a five-ring metal resistor, and the main circuit uses a five-ring metal film resistor with an accuracy of ±1% to ensure a good signal-to-noise ratio.
nThe PCB adopts 1.6mm thick double-sided sheet, 2.0 oz copper thickness, and the whole process of tin-spraying ensures the good passing performance of the current. First-class PCB quality.
nThe output uses a red ring high current inductor to ensure that the sound is crisp and powerful.
Attachments
It’s hard to say if it’s better. It appears to be a single amp in BTL (bridge tied load) vs the one I tested which uses two amp chips, each in PBTL (parallel bridge tied load) and each has its own bridge rectifier and power supply cap. The PBTL can handle double the current so probably can drive 2ohm loads even. Not that I ever use 2ohm speakers. The red Yuan Jing model you posted is about $38 and probably fine for most applications with a FR driver.
I also like it’s passive heatsink vs fans.
This one looks nice too and also has an output relay. It turns out that when you want a high wattage amp, a linear power trafo is a more economical way to get power. These use linear PSU vs a SMPS. When you need 48Vdc to 53vdc - dual rail SMPS are very expensive and quite noisy. Whereas a 25v 300VA toroid is about $30.
New Class D TDA8954 Two channel HIFi Digital Power Amplifier Board 210W+210W-in Amplifier from Consumer Electronics on Aliexpress.com | Alibaba Group
I also like it’s passive heatsink vs fans.
This one looks nice too and also has an output relay. It turns out that when you want a high wattage amp, a linear power trafo is a more economical way to get power. These use linear PSU vs a SMPS. When you need 48Vdc to 53vdc - dual rail SMPS are very expensive and quite noisy. Whereas a 25v 300VA toroid is about $30.
New Class D TDA8954 Two channel HIFi Digital Power Amplifier Board 210W+210W-in Amplifier from Consumer Electronics on Aliexpress.com | Alibaba Group
There is an intrinsic DCR R4 from the inductor included in the XO sim for the woofer but do not add any resistors to the woofer.
X what about the resistor in series with the capacitor which is parallel with woofer?470m(0.47 ohm or 470 Mega?)
so is it the 0.51Ohm resistor that you have specced?Do I need the branch(0.47/0.51ohm and 4.4uf in series) in parallel with the woofer?
Then the BOM would need to be changed to 6x 2.2uf
Also,since the 27uf x2 and 6.8uf are in parallel to make 60.8 ohm,any difference in just using a 56uf+5.1uf for 61.1ohm?
Then the BOM would need to be changed to 6x 2.2uf
Also,since the 27uf x2 and 6.8uf are in parallel to make 60.8 ohm,any difference in just using a 56uf+5.1uf for 61.1ohm?
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0.51ohm is same as 0.47ohm - not critical. Sometimes audio grade resistors are available in one but not the other.
Any combo that gets close to 60uF +/-5uF is fine. A larger value will pull the low corner down a bit, but since it is a first order -6dB/octave slope, the differences are probably not audible.
Any combo that gets close to 60uF +/-5uF is fine. A larger value will pull the low corner down a bit, but since it is a first order -6dB/octave slope, the differences are probably not audible.
I family acquaintance who is an audio enthusiast came by my apartment in Michigan last week to listen to the FAST speaker. This one is my wife’s setup and only powered with a Dayton DT-120 blue tooth amp. Also has a Polk Audio PSW10 subwoofer handling content below 60Hz. We had a good time and he has B&W 800D speakers and SS Macintosh amps in his home system. Despite only Class D amp and BT streaming from Amazon Prime on my phone, he liked it enough to listen for over an hour and was very impressed with the clarity, sound stage and imaging. I am pretty sure these speakers can hold their own with many commercial offerings costing a lot more.
Here is a photo of the system we listened to:
Here is a photo of the system we listened to:
Attachments
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Do you have Crossover for Dayton speakers RS225P-8A 8 "8 Ohm and Dayton RST28F-4 1-1/8 same box size for aerial speakers?. Thanks
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