Isn't it interesting how a person's equipment (most people only have one decent system if that) can so influence what they listen to even to the extent of shaping one's genre choices. Shouldn't be surprising I suppose but it can lead to seriously limiting one's music experiences. I tend to have a very eclectic taste and to me there is only one genre: good music. I have only recently realized this phenomenon myself and why I'm so interested in trying new systems and component combinations. Unfortunately, there is simply no perfect system at any price and it is not at all unreasonable to have multiple setups for differing music styles. With my primitive temporary setup, I have already discovered that some tracks sound better on my $12 FR's (not too many though...)
What I intend to do with the SET is only use it on extended range driver from about 150 Hz up and drive the woofers with a SS amp. I've also got a Tripath to put together to see what that's all about. I'm a tinkerer. Too bad it's so expensive of a way to be...
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Having tried adding an output transformer to a SS guitar amp, I'd say that the output transformer probably doesn't lower the output impedance. Someone with more knowledge than I could chime in at this point to give a definite answer, but I've read about speaker impedance interacting with output transformers (Morgan Jones' project using a FE167 has an article somewhere on here), and I'd guess that all those windings would struggle to reduce the output impedance.
Chris
Thanks for this thread guys, I've got a couple of low qts drivers that are bound for a second set of t-tqwt subs, but in the meantime, I was planning on trying out an open baffle design to see how it sounds.
I guess the good part about an open baffle is you really aren't wasting much wood if what you end up with is junk
I guess the good part about an open baffle is you really aren't wasting much wood if what you end up with is junk
Here's something that may be of use.
Variable Amplifier Impedance
Effects Of Source Impedance on Loudspeakers
http://www.diyaudio.com/forums/diya...peggio-loudspeaker.html?garpg=5#content_start
Variable output impedance was quite popular once of a day, as this would give much more flexibility in speaker choice.
Nowadays, commercial loudspeakers tend to be designed to be driven by a voltage source, so impedance varies wildly through the pass-band (3rd link).
Chris
Variable Amplifier Impedance
Effects Of Source Impedance on Loudspeakers
http://www.diyaudio.com/forums/diya...peggio-loudspeaker.html?garpg=5#content_start
Variable output impedance was quite popular once of a day, as this would give much more flexibility in speaker choice.
Nowadays, commercial loudspeakers tend to be designed to be driven by a voltage source, so impedance varies wildly through the pass-band (3rd link).
Chris
I also found the chart on this page to be very helpful in visualizing how the qts affects response: https://translate.google.com/transl...http://www.dipolplus.de/thema7.html&sandbox=1https://translate.google.com/translate?hl=en&sl=de&u=http://www.dipolplus.de/thema1.html&prev=search
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Thanks for this thread guys, I've got a couple of low qts drivers that are bound for a second set of t-tqwt subs, but in the meantime, I was planning on trying out an open baffle design to see how it sounds.
I guess the good part about an open baffle is you really aren't wasting much wood if what you end up with is junk
There doesn't seem to be much middle ground. Most folks either love, or hate, the sound quality.
I am researching OB speakers because I am thinking about building some. I haven't listened to any, so what aspect do people dislike about them?
Hi, well you've discovered Linkwitz Labs site so you're on the right track. If we forget the need for space and the work necessary for good bass, then I reckon what some may dislike about them is the more defuse soundfield....personally I prefer it, so it's a matter of taste. Some will say you can't get good deep bass from OB, but they are wrong . What you won't get is the thump in the chest pressurization if that's what you're after
. What you won't get is the thump in the chest pressurization if that's what you're afterYou would have to listen, and decide for yourself. Everyone has different tastes and their own built-in and imprinted sense of what "real" sounds like.
Here, please see the link for the longest discussion I could find. Bear in mind, these are just opinions. You will find that "pro OB" far outweighs the detractors.
So, since OB is the more popular, it must be right. Right ?
So - why DON'T people go with open baffle? - Techtalk Speaker Building, Audio, Video Discussion Forum
Hi all,
I came across this thread in a search for “low Qts woofer on OB” --- in reference to a speaker project I’m working on which mates a 12” woofer with a 10.5” x 46.5” ESL on a modified H-baffle, as shown here:
https://4.bp.blogspot.com/-xtBTeBU6...Fc7xR4_VBfnACLcBGAs/s640/H-baffle+12+SLS.jpeg
I’ve read many of MLK’s posts and MATHCAD simulations but I’m afraid they’re mostly over my head.
Anyway; I drew up this modified H-baffle hybrid ESL design for a friend who needs to go OB so that the speakers can be broken down to fit into his car with the seats folded down (big woofer boxes won't fit).
I/we are conflicted about the woofer choices in this application. My experience in building many hybrid ESL's is that a woofer optimized to blend with an ultra-low Q ESL crossing over at around 250Hz needs a low Qts( <0.4) and low inductance (< 0.7 mH). However, I'm reading that low Qts doesn’t work well on an OB-- at least, not without a lot of EQ’ing.
My friend has awesome subs, a DSP crossover and big Sunfire amps so there’s plenty of power and flexibility for EQ’ing and whatever woofer we choose can be unloaded to the subs below [let’s say] 60-80Hz. This may allow going with a lower Qts.
Even having subs, it would be nice if the speakers could be at least listenable without them. But I’ve never built an OB so I don’t really know what’s reasonable in this case for the woofer’s Qts and EQ’ing.
How low can I go??
I’m thinking we might need to split the difference—not optimal for either the ESL or OB but somewhere in between. My friend is looking at some AE woofers (IB type) but I’m leaning towards one of the two Eminence woofers below, with added EQ’ing as required (I especially like the BL product on the Kappa-Lite 3012LF -- should really thump):
Speaker Detail | Eminence Speaker
Speaker Detail | Eminence Speaker
Opinions and advice are appreciated… and if anyone thinks I’m nuts, I would need to hear that too.
Thanks!
Charlie (a.k.a. Jazzman)
Jazzman's DIY Electrostatic Loudspeaker Page)
I came across this thread in a search for “low Qts woofer on OB” --- in reference to a speaker project I’m working on which mates a 12” woofer with a 10.5” x 46.5” ESL on a modified H-baffle, as shown here:
https://4.bp.blogspot.com/-xtBTeBU6...Fc7xR4_VBfnACLcBGAs/s640/H-baffle+12+SLS.jpeg
I’ve read many of MLK’s posts and MATHCAD simulations but I’m afraid they’re mostly over my head.
Anyway; I drew up this modified H-baffle hybrid ESL design for a friend who needs to go OB so that the speakers can be broken down to fit into his car with the seats folded down (big woofer boxes won't fit).
I/we are conflicted about the woofer choices in this application. My experience in building many hybrid ESL's is that a woofer optimized to blend with an ultra-low Q ESL crossing over at around 250Hz needs a low Qts( <0.4) and low inductance (< 0.7 mH). However, I'm reading that low Qts doesn’t work well on an OB-- at least, not without a lot of EQ’ing.
My friend has awesome subs, a DSP crossover and big Sunfire amps so there’s plenty of power and flexibility for EQ’ing and whatever woofer we choose can be unloaded to the subs below [let’s say] 60-80Hz. This may allow going with a lower Qts.
Even having subs, it would be nice if the speakers could be at least listenable without them. But I’ve never built an OB so I don’t really know what’s reasonable in this case for the woofer’s Qts and EQ’ing.
How low can I go??
I’m thinking we might need to split the difference—not optimal for either the ESL or OB but somewhere in between. My friend is looking at some AE woofers (IB type) but I’m leaning towards one of the two Eminence woofers below, with added EQ’ing as required (I especially like the BL product on the Kappa-Lite 3012LF -- should really thump):
Speaker Detail | Eminence Speaker
Speaker Detail | Eminence Speaker
Opinions and advice are appreciated… and if anyone thinks I’m nuts, I would need to hear that too.
Thanks!
Charlie (a.k.a. Jazzman)
Jazzman's DIY Electrostatic Loudspeaker Page)
Hi. Normally a very shallow H-frame like yours is going to need all the help is can get. If you use something deeper it won't need as much EQ, though with a crossover at 250Hz you may have a problem with cavity resonance and since you only want to hit 80Hz you could probably get away with your design. A simulation would be your best bet
Thanks for your reply. I've modified my drawing slightly and added some dimensions. Unfortunately, I have no idea how to use any of the simulation software or calculate the cavity resonance. Absent the ability to model it, I'm left with only the trial and error approach.
Attachments
Woofer Qts doesn't matter much as long as have enough voltage headroom in the power amp for EQ.
Its a myth that a low Qts woofer eats more power than a similar one with higher Qts. It needs more voltage (to overcome the higher motional "back EMF" voltage) but way less current (because of the better force factor).
Remember that Qts is a parameter *external* to the woofer as it mainly depends on the output impedance of the amplifier. If you have a current-drive amp then Qes (normally dominating the Qts) goes infinite and Qts equals Qms. To make the same movement the driver always needs the same terminal voltage no matter what the driving impedance is, hence the exact same power is dissipated in the voice coil resistance regardless of effective Qts.
Its a myth that a low Qts woofer eats more power than a similar one with higher Qts. It needs more voltage (to overcome the higher motional "back EMF" voltage) but way less current (because of the better force factor).
Remember that Qts is a parameter *external* to the woofer as it mainly depends on the output impedance of the amplifier. If you have a current-drive amp then Qes (normally dominating the Qts) goes infinite and Qts equals Qms. To make the same movement the driver always needs the same terminal voltage no matter what the driving impedance is, hence the exact same power is dissipated in the voice coil resistance regardless of effective Qts.
Speaking for myself, I dislike the size.
I made mine as small as I could, using a full range on folded open baffles, intending to use them on stands with a separate sealed subwoofer.
I wound up with the smallest OB woofer panels (also folded) I could get to work, as speaker stands for distributed mono bass. Each array is now about 53 inches tall and 27 inches wide, front view.
I've tried acclimatizing to both sealed and vented, and distributed box bass, but can't quite love it with OB mains.
