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- ani_101 5:40AM
- rjj45 5:40AM
- Steve_Lee 5:40AM
- Tieftoener 5:40AM
Because she let me.
Started a new project today because my chubby eggs are nearly done and because my wife let me. This one is my attempt at a more traditional speaker. It is inspired by the KEF Blade. It uses budget drivers on the shelf. Passive three way, tall and skinny but with a robot inspired arms swept back and splayed out. OK it's another TL. Gotta either get this outta my system or maybe not. Overall taper ratio is 8. I think two different tapered line will be sufficient because the woofers have a pretty high Q. Oh ya the drivers will be ND140-8 dual opposed with dowel rods connecting them at their screw locations. Like Brad did on his big boys. I think those speakers could poop a speaker like these. Oh ya also the MTM will use Peerless tC9fd18-08 mids and Dx20bf tweeters. I am hoping to achieve 2nd order acoustic slopes at 350 and 3.5K. It's always good to have wife approval but I still have to constantly remind myself that
this is a budget build.
and 1 other.
Comments
Budget doesn't mean low performance. I know from experience that the Mid-tweet combo will work well and the ND-140 will dig deep.
I think you have a great combo, I'm looking forward to this build.
Interesting build
Oh ya, The mids will be aperiodic loaded. I have a resistive vent idea where the binding posts are.
I bought the mids from you. I shall give you the appropriate recognition.
I would not have remembered that had you not said something. Happy to see them getting used.
Im totally digging the aesthetics.
I assumed having the drivers at the beginning of a TL was not favorable. Is this not always true?
True, offsetting the woofer down the line does help the overtones from being so severe. I am hoping that the combined effect of the two or three lines with very different tapers will eliminate these overtones. Should be easy with these high Q woofers. I also plan to document this with squiggly lines for all you squiggly line guys out there.
You have the makings for a great sounding speaker there! Cool design, reminds me of Bill’s Linehoppers.
I thought the same thing....
InDIYana Event Website
Something like this
I have problems at 170 Hz. Nearfield woofer shows a slight dip. Terminus shows a 6 Db. bump. It gets much worse at one meter. Can't make it better with the multi taper trick. I am thinking about going powered with these. Cheap powered like 30 bucks per China Amp. 2.1 TPA3116
Tried a passive crossover yesterday. I am not sure what is going on with these dual opposed woofers. I mocked up a crossover with 4th order slopes at 400 and 3500. I had to attenuate the mids almost 10 Db. I still have a dip at 150-170 range. Inverting woofer polarity causes a deeper dip but less broad and better coupling to the mids. I have tried them upside down on my stands with the terminus at 6 foot height, the problem remains.Blocking the terminus has no effect on the cancellation. They don't sound awful. It must be caused by time alignment. after entering in the physical Z location of the mids, zero, and the woofers,+160mm down, Y axis and +200mm back, Z axis.I got a good match to my combined overlay by entering a acoustic offset of +37 microsec. for the mids and 300 microsec. for the woofers. I'm pretty sure I did it right because the response looked good. I think I need to go with DSP ampl. to get a lower XO, 150 Hz and better time alignment. I am thinking about putting a KABD 4X100 amp in each speaker and replacing the woofers with WL-150 4 Ohms or something better. I could eliminate the dual opposed and go with a single side firing woofer but I am concerned about vibration. The vibrations would be at 90 degrees to the mid movement so is it even something to worry about? Tell the old new guy what you think.
I've been tinkering with the idea of using a sub plate amp w/ speaker level inputs to drive woofers in a tower and use it's built in lowpass. It effectively separates it into a bookshelf speaker with subwoofer. As long as the midbass drivers can handle getting bass. Might be able to get away with less padding on the MT section and crank up the gain on the plate instead. Crude? yes, but might just get the job done.
That's not crude, it is a proven approach to things. Go for it. I have similar plans in place.
Yeah all up to viewpoint and interpretation. I tend to see elegance in simplicity while others might see crudeness in the downsides of a "less highly engineered" product. One man's trash is another man's treasure.. and all that.
What i neglected to mention was i imagine time alignment would be less of an issue if crossing down in the sub range. So just using plate amp/s might get ya across the finish line without needing to go down the "active" rabbit hole. And, with the woofer sensitivity in a TL, probably wouldnt break the bank on power requirements.
Eggguy, maybe I am not following you, but that dip at 150-170Hz sounds like the typical 1 meter microphone measurement distance floor bounce to me. I would simply ignore it. These dips tend to even out as you move back to the listening position.
JR/Drew, I'm doing the same thing with my Micro Grand Utopia build. Two sub plate amps w/ speaker level inputs to drive separate subwoofers with the smaller MT speakers sitting on top of each sub cabinet.
You are probably correct, and maybe it is more noticeable on omnimic due to it opperating dual opposed
I would also assume floor bounce cancellation, really not a big deal.
+1
InDIYana Event Website
Thanks, it just stuck out like a sore body part. The KEF blade has an XO of 350Hz, but I just think a lower active XO would better. This robot speaker pair may not ever dance, I think I will put it in a corner where I can see it on occasion and think about it. Well begun is half done. Poorly conceived is something that rhymes with conceived but is not that.
Poorly conceived is necessary to leave
Have you listened to it yet? I have founf thet If something measers crappy over 10k and/or under 300 it might still be amazing.
I plugged the woofer holes and moved them down 7 inches or so because I was having a tough time getting rid of the 3/4 wavelength overtone. You know, the nasty one. I haven't made a TL with such a long straight portion in probably 30 years. Also the tuning was too low, it still is. The sensitivity is also pretty low. So I think the woofers need to be replaced. I feel like the mid chamber is too shallow. Vocals sound hollow. So I need to get a denser material behind them or modify the chamber. The MTM XO needs to be lowered because of vertical lobing at 10 foot distance.There is a pretty big difference between sitting and standing. There is plenty of room in the XO compartment that I could make them powered, either now or in the future. So thats a plus. And they are going to look cool. If I do proceed, I am going to try to make a dark metallic stain with clear stain base and pearlescent powdered pigment, distress some of the areas that would receive wear if it were a real moving robot. I was also going to try a rust colored glaze to some of the nooks and crannies, as if he has been left out in the rain a time or two. Ole rusty, the big footed tripod. In other words, something that my wife will not understand. She might say something like, you're not planning on bringing those into the house are you?