Health and finances (or lack of both, rather) kept me away from the net too long. And as to Doraville...no village can be as nice as it is in our memories. Most of my part of the town is Turkish by now, and, being very fond of garlic I can't say I mind. Furthermore many of them like folk music and are grateful when I build them an affordable set of speakers. Not having to explain why full range speakers are better than fourway100000 watts, that's nice, they just accept an old geezer's verdict and have me build a pair. Plus - their wives are not used to be asked their opinion...you ask them which colour they would like and you have a new friend.
Speakerbuilding is fun - and when I sell a few more I'll be able to afford something decent for myself. Headphones are nice, but I miss that KICK.
Pit
Speakerbuilding is fun - and when I sell a few more I'll be able to afford something decent for myself. Headphones are nice, but I miss that KICK.
Pit
I not sure either but I think it’s because the shielded drivers were developed for ported boxes and the non shielded for back horns. The non shielded drivers roll off more rapidly because they’ve been designed to take advantage of the back horns contribution of bass/mid bass reinforcement. Therefore non shielded can have slightly higher efficiency in the upper frequencies.
I notice the dip in response too when modeling non shielded Fostex drivers in ported boxes.
I notice the dip in response too when modeling non shielded Fostex drivers in ported boxes.
Greets!
Only to the extent of its Qes:
n0 = (K*Fs^3*Vas)/Qes
SPLeff = 112.018+(10*log10(n0))
where:
n0 = reference efficiency in percent
K = 9.6352e-10 (Vas in liters)
K = 9.6352e-7 (Vas in cc)
K = 2.723e-8 (Vas in ft^3)
Notice that Fs (mass, suspension compliance) dominates.
How powerful the driver's motor is sets its mass corner (Fh = ~2*Fs/Qts), so this governs its flat passband base efficiency with inductance controlling its base HF roll off. Its mass, compliance, diaphragm and/or whizzer geometry/materials, etc., determines any rising on-axis response (break-up modes). The former is all boring, easily calc'd physics and anyone who has some experience need only look at T/S specs to get a good idea of how it will perform in various alignments, but the latter is where the art of driver design is, so measurement is de riguer for the most part to know its wide BW performance.
Bottom line, if you were to partially de-magnetize a FE206E it wouldn't have a FE207E's response or vice versa except in its < Fh BW.
GM
Only to the extent of its Qes:
n0 = (K*Fs^3*Vas)/Qes
SPLeff = 112.018+(10*log10(n0))
where:
n0 = reference efficiency in percent
K = 9.6352e-10 (Vas in liters)
K = 9.6352e-7 (Vas in cc)
K = 2.723e-8 (Vas in ft^3)
Notice that Fs (mass, suspension compliance) dominates.
How powerful the driver's motor is sets its mass corner (Fh = ~2*Fs/Qts), so this governs its flat passband base efficiency with inductance controlling its base HF roll off. Its mass, compliance, diaphragm and/or whizzer geometry/materials, etc., determines any rising on-axis response (break-up modes). The former is all boring, easily calc'd physics and anyone who has some experience need only look at T/S specs to get a good idea of how it will perform in various alignments, but the latter is where the art of driver design is, so measurement is de riguer for the most part to know its wide BW performance.
Bottom line, if you were to partially de-magnetize a FE206E it wouldn't have a FE207E's response or vice versa except in its < Fh BW.
GM
Understanding Speaker Specs
GM and others,
Thanks for the answer to my Query: why shielded drivers sim differently than non-shielded.
Short Q to add to that: Since I know almost 0 about what the different specs mean for a driver, where can I start reading to try to get up to speed? To give you an idea of how ignorant I am, I don't know if amp output to a driver is AC or DC. If AC then I am wondering if using inductors and caps and resistors to tune a drivers impedence is akin to tuning the sytems POWER FACTOR(Watts vs VARS) to maximize watts? Sorry, I know this is OT, but you know that beginners are attracted like bees to honey to a thread like this one. Would appreciate a prod in the right direction.
Cheers,
Erik
GM and others,
Thanks for the answer to my Query: why shielded drivers sim differently than non-shielded.
Short Q to add to that: Since I know almost 0 about what the different specs mean for a driver, where can I start reading to try to get up to speed? To give you an idea of how ignorant I am, I don't know if amp output to a driver is AC or DC. If AC then I am wondering if using inductors and caps and resistors to tune a drivers impedence is akin to tuning the sytems POWER FACTOR(Watts vs VARS) to maximize watts? Sorry, I know this is OT, but you know that beginners are attracted like bees to honey to a thread like this one. Would appreciate a prod in the right direction.
Cheers,
Erik
Re: Understanding Speaker Specs
Greets!
You're welcome!
Speakers have AC motors, so if fed DC (infinite BW) they will just off-set based on polarity and commence to overheat/let all its smoke out.
WRT T/S, if it's not here, you probably don't need to know it: http://home1.stofanet.dk/cfuttrup/dpc/dpc.htm
In the days of high output impedance tube amps, yes, the primary object was to maximize energy transfer, but with today's vanishingly low output impedance amps we use them to XO between drivers and passively shape the speaker's response, though sometimes impedance compensation is required to achieve this.
GM
Greets!
You're welcome!
Speakers have AC motors, so if fed DC (infinite BW) they will just off-set based on polarity and commence to overheat/let all its smoke out.
WRT T/S, if it's not here, you probably don't need to know it: http://home1.stofanet.dk/cfuttrup/dpc/dpc.htm
In the days of high output impedance tube amps, yes, the primary object was to maximize energy transfer, but with today's vanishingly low output impedance amps we use them to XO between drivers and passively shape the speaker's response, though sometimes impedance compensation is required to achieve this.
GM
Re: Re: Understanding Speaker Specs
GM,
Thanks much for the reply. After I posted I thought about it and concluded that it had to be AC. I have been needing to put cans of smoke on my shopping list less and less as the years go by. I guess I must be getting more careful. Not letting it get out as often. I appreciate the link and all I have learned so far in reading through this and other threads.
Cheers,
Erik
GM said:
GM,
Thanks much for the reply. After I posted I thought about it and concluded that it had to be AC. I have been needing to put cans of smoke on my shopping list less and less as the years go by. I guess I must be getting more careful. Not letting it get out as often. I appreciate the link and all I have learned so far in reading through this and other threads.
Cheers,
Erik
