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Klipsch style tower project on the cheap
Build log is on PE TT, but thought I'd share the results here since it seems many aren't active over there.
Aiming for Heresy type sound but tower versions. My first go at a 3-way. I call them Faux Pas.
Tweeter is a P-audio pht-409. B-52 buyout ebay special ($36-44/pair shipped depending on scratch and dent or blemish free) Initially I tried some titamium diaphragms but settled on the factory phenolic polyimide ones. (EDIT) looks like prices have gone up to $50 shipped for "blemished" ones and $60 shipped for unblemished.
Midrange CD is from an MCM 53-1240 (discontinued, though I suspect is the same as the 53-1245 with a different horn). Titanium 1.75" Diaphragm. The horn from the 53-1240 looked the part, but had some issues and I found the Dayton H812/Celestion H1-9040P seemed to pair well for a $40 horn/CD combo.
Woofer is MCM 55-3212. 4ohm 12" PA style. $19 currently on Newark. Tried a few others before settling on this one.
Both enclosures were built from a single piece of Sande hardwood plywood. Bases are made from 1x2 pine.
After much toil I settled on 3" precision port on the front. Stuffed the bottom and top of the enclosure quite a bit to try and tackle the transmission line effect of the tower. I decided to try applying wood veneer for the first time also. Finished with a tannin reactive stain and clear oil based poly spray. Ended up with a distressed oak look.
In-room response
THD
and 3 others.
Comments
Very impressive!
Rockers!!
I'll bet they sound powerful, especially if placed near the room corners . . . Nice job!
The measurement was taken several feet from any wall, but my living room is small, and placement options are limited. Keeping them only a few inches from the wall becomes necessity to live with. Due to that I really didn't bake in much of any baffle step. Lean and punchy is how I'd describe it. I'm sure they would seem bass light away from the wall in a larger room.
Just upgraded my receiver to a Denon DRA-800h. The DAC on the hdmi inputs absolutely blows the doors off my previous Pioneer... and now have 120W/ch (at 6ohm) to play with. These speakers I'd call 4ohm, but they should be well over 90db/w 1m.. I doubt I'll ever crank it over half volume.
The phone camera seems to have a hard time picking up color correctly with the led lighting. This is closer
Very nice! I would bet they sound even better than most Klipsch models too. Only $100/side in drivers? Amazing!!
I wanted to be sure the distortion wasn't a fluke from the measurement not being loud enough. The last measurement I took, verifying drivers were wired correctly, was at higher volume. I updated REW but still can't find how to show fundamental and distortion at the same time. I ended up saving the screenshots and copy/pasting the fundamental graph over the THD graph.
I was originally having issues with the midrange distortion peaking even higher (below 1khz), but seems my final tweak raised the crossover enough to knocked it down.
Not being critical of your efforts Drew, but this graph set indicates that the THD is higher now around 1.2K than it was in the previous ^ graph - Any ideas as to why?
In any case, you have done a spectacular job considering the legacy of the chosen drivers, man - I mean, seriously.
Good job - and this is with PASSIVE components, not DSP.
No problem at all. I grew a bit skeptical of the original data I posted anyway.
That measurement was roughly 5db louder to keep distortion measurable above the noise floor for a more reliable result. Still seems to be roughly 45db down from the fundamental in that area so I'll take it.
I wouldn't have gotten it to this point if it wasn't for you guys who posted on the PE TT thread helping out. Guess it gave me enough motivation to stick it out. 3-ways suck to design lol. Not sure if I'll try another.
I think you will - one is never enough!
Little update since I've been rocking these full time the past couple months.
Initially the slump in the midbass was pretty noticeable and a bit disappointing. I wondered if my receiver amp was struggling as bass seemed stronger the first few songs played in a session. Was hard to tell. Maybe I was just getting used to the bass level, and then the midrange forwardness would start to take my attention.
I brought them over to a buddie's neighbor who has a home theater just to see how they would do playing music in that space. Open floorplan basement with about as much square footage as my entire house. The screen was rather centered in the space too (maybe 2/3 offset). So about as worse case scenario for these speakers as it can get. And it showed. Was like the woofer wasn't even there. I suppose he could have had some EQ applied for his own speakers, but he insisted it was all set full direct. The horns could clear the room with volume, but was otherwise unfulfilling. These definitely need all the room/boundary gain they can get. Not surprising as that is how I designed it. Due to that I doubt Ill bring these to InDIYana. They just wouldn't sound good in a bigger space as-is.
Back home, in the last few weeks I've been dialing in placement. Bass/midbass deficiencies are seeming less noticeable either from more break-in or me just getting used to it. I did recently shove them the last couple inches to the back wall. One is pretty much in the corner of my rather small living room (11.5'x15'). Light toe-in seems best with the center line of each firing probably 18+ inches away from each ear. I also plopped em on some 6" stubby stands. Brings the mid horn up towards ear level. Seems to keep me from hunting around so much for the sweet spot. Thinking of building some booster bases out of 1x6 material that the existing attached bases nest into.
It is hard for me to describe the dynamics. It isn't something I outright notice in music, besides seeming a bit more punchy and forward at times. But last night I played a movie. Set the volume level to reasonably hear the dialogue. Then gunfire and explosions were not just surprising... but ear splitting. Even the woofers woke up and jiggled my insides without sounding strained.
Would I suggest someone else build them? eh. If they will be in a smallish room and distilled down the build to the necessities without spending the extra money on fancy finishes/plywood I suppose they bring some interesting things to the table for the money invested. Drivers/horns and crossover components come in around $300 per pair before shipping/taxes. Just beware the QC on MCM drivers isn't super great. I did get a bit of a stinker for one of the mid CDs, but fortunately I ordered 3 to have a spare. I think they got a little overzealous with the glue on the phase plug so hoping that is the cause instead of a bum diaphragm.
Just played these at Detroit. Was pleasantly surprised the bass actually showed up to the party. Was leaner than the others but wasn't the horror show I thought it would be
These exceeded my expectations, well done.
Thank you! Helps me know I'm at least going in the correct direction.
And for the record I did finally figure out the distortion graphs more. So here is a bit better one from that same measurement with the fundamental flattened. 3rd order (orange) stays below 45db down except that peak at ~230hz. I guess this is what I'm most proud of from this project. Something I'm not sure I'll be able to match again for a similar cost.
Though I do have a pair of nice cast basket 15"s from a PE garage sale that is taunting me to do a Cornwall clone (facepalm).