You're welcome!
No.
With its conglomerate set of specs used up till now, allowing many parts to be made in humongous bulk, seems a good choice overall at a very cheap/'fair' consumer price.
No clue, got ~politely 'drummed' off the forum shortly after joining [though still a member last time I checked] for 'having a clue' WRT audio speaker/system design and not actively promoting all things P.E., though if its specs/response plot is reasonably accurate, then its technically max usable XO point is ~13543/12 = ~1129 Hz, i.e. 'setting' on the baffle/~160 deg [normally misnamed 180 deg/2 pi space] with any higher beginning to beam based on its design, which at the oft used ~90 deg = 1500-1600 Hz range depending on diaphragm profile, VC dia..
GM
When inductance is insignificant [at least in its intended pass-band] and otherwise meet published specs < +/- 10%, making your earlier sims now accurate 'enough' assuming there's no significant series resistance to raise Qes/Qts.
Re box alignments, T/S theory peters out at the driver's upper mass corner, ending at its lower mass corner, i.e. Fs is the mean.
Fhm = 2*Fs/Qts'
Flc = Fs*Qts'/2
Qts' = Qts + any added series resistance [Rs]: HiFi Loudspeaker Design
GM
Ok, I did some research and found a whole thread about the meaning of "Q": (GM Quote) i So if I'm understanding correctly, a speaker with the proper Q-value (is that generally considered to be .707?) will have more accurate transients. We can't always get the Q we want in the enclosure we have, so the rest of the quote in my previous message appears to show how to raise Qts of a driver and its enclosure by adding series resistance to the signal. The reason for raising the Q would be to get more accurate transients than expected by the driver/enclosure combination alone. (an overdamped wave would not be loud or sharp enough, and an underdamped wave will be boomy)
Am I in the ballpark?
I still don't understand when induction is insignificant... I thought a driver's LE (voice coil inductance) is constant through it's frequency band, and in general, that lower LE's are related to reduced distortion.
Thanks - Six.
Well, there are many different Q's. On the driver; there is
Qms
Qes
Qts
And, for closed box; there are other "Q's" and for vented box even different "Q's"
Take a look at this from the Eminence pro driver site:
Understanding Loudspeaker Data | Eminence Speaker
and more
HiFi Loudspeaker Design
and this...
HiFi Loudspeaker Design
HiFi Loudspeaker Design
Maybe you already knew some or most of this? Handy anyway...
Qms
Qes
Qts
And, for closed box; there are other "Q's" and for vented box even different "Q's"
Take a look at this from the Eminence pro driver site:
Understanding Loudspeaker Data | Eminence Speaker
and more
HiFi Loudspeaker Design
and this...
HiFi Loudspeaker Design
HiFi Loudspeaker Design
Maybe you already knew some or most of this? Handy anyway...
Thanks Oldspkrguy, I am generally familiar with the terms, but have not applied them to a specific build like what I'm planning now. It's becoming clearer how the Q of the driver affects whether a vented or sealed box is a better option. Also how big a box some of the vented drivers require!
I'm getting a better understanding that when I choose a specific driver, the size of the box will affect the overall Q of the assembly. (and also the size of the box is somewhat dependent on the Qts of the driver) I think GM is proposing a workaround: if a box can't be as big as the driver needs for optimal Q, then the Q can be raised electrically by adding a series resistor, providing optimal Q in a smaller box (though that seems like it would impact max volume at a given frequency too) Stuffing with sound insulation should also help that.
Final note: I've requested more information from various sources re: the 3 drivers I have narrowed it down to: Eclipse, Goldwood and Peerless/Tymphany. I'm beginning to sketch the speaker dimensions, and should have some CAD files soon. I'm moving forward with adapting the FR driver to the horn. There is progress, just slower than I wish it were.
Thanks! - Six.
I'm getting a better understanding that when I choose a specific driver, the size of the box will affect the overall Q of the assembly. (and also the size of the box is somewhat dependent on the Qts of the driver) I think GM is proposing a workaround: if a box can't be as big as the driver needs for optimal Q, then the Q can be raised electrically by adding a series resistor, providing optimal Q in a smaller box (though that seems like it would impact max volume at a given frequency too) Stuffing with sound insulation should also help that.
Final note: I've requested more information from various sources re: the 3 drivers I have narrowed it down to: Eclipse, Goldwood and Peerless/Tymphany. I'm beginning to sketch the speaker dimensions, and should have some CAD files soon. I'm moving forward with adapting the FR driver to the horn. There is progress, just slower than I wish it were.
Thanks! - Six.
A 0.707 Qtc' is a max flat alignment, i.e. F3 = Fb, so the default. 0.5 Qtc' = transient perfect, so the ideal with a Qtc' = 1.0 historically being the acceptable upper limit before' ringing' becomes increasingly audible.
The reason I normally add the Qts' or Qtc' note is that at the very least there will be some resistance in the speaker wiring, any passive filter that will raise Qts/Qtc, which online or otherwise calculators often don't account for, though admittedly it's not enough to matter [default = 0.5 ohm] if driven with a typical low output impedance amp [SS] + some form of DSP is used.
Plenty of newbie low DF tube amp owners have been 'caught out' though with excessive [seriously under damped] 'smiley face' EQ'd speaker systems.
Right, you raise Qt to 'fill up' a too large [over-damped] box to the desired Qtc if sealed or Qtb for vented.
Not its entire pass band per se as increasing Le reduces usable pass band.
Look at a driver's impedance curve and note how much quicker it rises with increasing inductance and how that affects frequency response Vs a sim done by a program that doesn't account for inductance.
Early on a lot of folks were really upset with their speaker's inferior performance that simmed 'flat as a billiard table' over a decade only to have a 'one note' boomer using a cheap high inductance woofer.
GM
If you have been following my thread on 3 1/2 way...; I have been playing around quite a bit with my existing drivers; boxes; X/O, etc. I think the NE265 will do what I'm after but that is on temporary hold. So if you DO end up with the "Peerless" ( they keep changing names) before me; I'm very curious about what your listening impressions will be. I could use two each per side of the Satori 7 1/2 but only the 4 Ohm version. The calculators show only one 8 Ohm version for that box size. Of course; two each of the 7 1/2 4 Ohm would have to wired in series; this sort of defeats one of my goals for higher SPL. AND, four of these is getting way beyond my budget.
Audio Technology 10 inch is considered by some to be the world's best. If I had the funds; I would go for it...but then; there is the box size again...my project isn't getting any easier either!
Sandwich cone
Cheers!
Found Vance Dickason's review from July 2010's issue of Voice Coil... (Scroll down to P-7) Very interesting, looks like the driver does what it's advertised to do.
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Project Update 7/9/2020
I've ordered four Peerless/Vifa/Tymphany NE315w-04's - they should be here by End of July, early August 2020.
The next phase will be to build and test the optimal enclosure for the woofers, since calculations show that a small 48L / 1.8 cu.ft enclosure is all that is needed for a sealed cabinet with F3 near 45 hz.
I hope to evolve this thread into a documentation of my build. I am doing this in my spare time (above an beyond the list of Honey-Do's I already have). So I will ask for your patience as this may take some time.
Thank you to all that provided input so far, I hope I can give back some learnings through the next phase.
Six - Minneapolis.
I've ordered four Peerless/Vifa/Tymphany NE315w-04's - they should be here by End of July, early August 2020.
The next phase will be to build and test the optimal enclosure for the woofers, since calculations show that a small 48L / 1.8 cu.ft enclosure is all that is needed for a sealed cabinet with F3 near 45 hz.
I hope to evolve this thread into a documentation of my build. I am doing this in my spare time (above an beyond the list of Honey-Do's I already have). So I will ask for your patience as this may take some time.
Thank you to all that provided input so far, I hope I can give back some learnings through the next phase.
Six - Minneapolis.
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