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Greg, your system is prob a fair bit more sensitive than that I'm guessing.
Well, if we don't count below about 80Hz, sure we are closer to 96-97dB. But yeah, 91dB to nearly 20hz is fantastic. Movies are gonna be a blast!
Make sure to play some pink noise(only a single speaker) when you get them back and move your head up and down. I'm curious with such a high crossover point and rather large separation of the mids, what kind of lobing you're getting. Then again, Dennis knows what he's doing, so I'm sure your results will be excellent.
Well, if we don't count below about 80Hz, sure we are closer to 96-97dB. But yeah, 91dB to nearly 20hz is fantastic. Movies are gonna be a blast!
Make sure to play some pink noise(only a single speaker) when you get them back and move your head up and down. I'm curious with such a high crossover point and rather large separation of the mids, what kind of lobing you're getting. Then again, Dennis knows what he's doing, so I'm sure your results will be excellent.
Greg
Knowing what that tweeter will do, I was kind of surprised by that crossover point too. We used it at 1100 Hz with a 10" woofer. Then again, I'll bet Dennis' crossover is simpler than ours wound up being. It took some creative shaping to wrench the response of the TPL150H into a smooth 1100Hz LR4. Crossing it higher would definitely simplify things.
Well the tweet is very narrow in vertical dispersion already. Add to that a c to c distance of about 14" on the mids and the loving that goes with that and you have a very narrow vertical sweet spot to say the least.
Sadly I don't have any real grasp on the lobing effects involved with MTM's or which frequencies are generally acceptable with which c to c separation. Is it 1 wavelength at crossover freq that is the rule of thumb? This design is more than 2 wavelengths c to c distance at that crossover freq. I am just taking that crossover freq from a plot Dennis sent me. It didn't show any reverse nulls etc so 2.7k is a guess.
I would've think of a bit lower crossover too, but like I said I haven't heard them yet.
Well the tweet is very narrow in vertical dispersion already. Add to that a c to c distance of about 14" on the mids and the loving that goes with that and you have a very narrow vertical sweet spot to say the least.
Sadly I don't have any real grasp on the lobing effects involved with MTM's or which frequencies are generally acceptable with which c to c separation. Is it 1 wavelength at crossover freq that is the rule of thumb? This design is more than 2 wavelengths c to c distance at that crossover freq. I am just taking that crossover freq from a plot Dennis sent me. It didn't show any reverse nulls etc so 2.7k is a guess.
I would've think of a bit lower crossover too, but like I said I haven't heard them yet.
Loren
That is the nice thing about an active crossover, a couple clicks a couple measurements and you can find out.
“Never ask people about your work.”
― Ayn Rand, The Fountainhead
That is the nice thing about an active crossover, a couple clicks a couple measurements and you can find out.
Well, my BSS 9088ii 8x8 iir capable DSP arrived two days ago. It is a vintage piece but has a good reputation for sound quality. I don't have the 6 channels of amplification in hand yet though. Plus I'm not experienced with measuring or with knowing which things to apply DSP to and which to leave alone. That's why I'll be having a friend help me with that. I hope that I can learn in the process.
In the meantime I will enjoy Dennis crossover. And it will be an interesting to compare a well implemented DSP based speaker to the same exact speaker with a passive crossover designed by a well respected design guru.
Who knows, the passive version may well sound better.
All kinds of fun.
Loren
Yes, JohnK uses it for his Nao open baffle speakers. You have to have a computer with 2 PCI slots for the M-Audio Delta 1010LT cards in order to utilize all the available inputs and outputs.
Yes, JohnK uses it for his Nao open baffle speakers. You have to have a computer with 2 PCI slots for the M-Audio Delta 1010LT cards in order to utilize all the available inputs and outputs.
That would be a great system, especially for someone that uses SoundEasy.
Crossover parts are here. Time to start soldering. I hope to pick up the speaker from Dennis on Sunday and have them up and running at that point.
The crossover has 16 components total per side. Some of those resistors and caps in the pics will be paralleled. The Clarity caps are mostly becuase they are what Madisound had in stock in the correct values, and PE was out of stock on some needed values. Here is a FR plot of the system output from Dr. Murphy's software. The sim is based on the drivers as measured in the fully assembled speaker.
Looks to be +/- 2 db up to that peak at 18khz which I doubt will be any kind of issue.
Wow, I know I've been gone quite a while on this thread. One month today. In that time I have gotten the speakers completed (well just MDF boxes but functionally completed).
I am really really VERY pleased with how they sound. My most succinct description is that they are like listening to a very good pair of headphones with the welcome addition of real palpable impact. I think they have a very up front presentation, not to say they have a forward tonal balance because they certainly don't. They do however have a very direct presentation with excellent detail and clarity. It is really impressive to me how much of a difference a three way with a woofer handling the entire bass range vs a sub/sat system makes on things like a bass played with a bow in classical music or any number of other things. The highs are airy and extended with all kinds of presence but no hint of brightness or sibilance. I am loving the paper cone mids. The bass section was in an alignment tuned to 22 hz that gave a gently sagging response from 45 hz down to 20 hz then cut off steeply below that. The 3-4 db difference in that 20 to 45 hz range was definitely audible compared to Dennis's Phil 3's which are flat anechoic down to about 25 hz or better. I changed to a shorter vent that has an Fb around 27 that has a flat response down to F3 at 25. That made a noticeable difference for the better on music, but the DEEP infra bass stuff will probably be missed on movies. When I get to active DSP implementation I could go back to the deeper tuning and dial in some EQ to fill in that 20 to 45 hz range while still doing over 111 db down to 18 hz.
Anyway, here are some pics of what they look like and of some of the build steps.
That last pic in the post above is the method I used to get the woofer template done. Here are a couple more of the pics of that. The pic of the test cutout that has all the slop/extra space is one I did before I got the centering pin to use with my guide bushing base for the router. The difference isn't subtle.
Here is a little more stuff from some pics. The two response plots are the sims from the measurements Dennis did with the drivers in cabinet in his room. Anyway the one with the lower crossover has a big diffraction dip at the bottom of the tweeter's range so that is a big part of why he chose the higher crossover frequency.
These are the crossover schematics. 29 is the woofer, 30 is the mid and 31 is the tweeter (in case you couldn't tell which I'm probably too dumb to do just looking at them).
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