Hi,
I saw your post about your corner loaded line arrays and it made me join the forum
Welcome to AudioNervosa Tinnitus Towers!! Thanks for describing your system and how much you like it. That is inspiring to me, thanks. I've heard a few multiway arrays, never really been impressed with them, but they were all passive crossover 2 ways. I've had the urge to build these full rangers since I saw John Murphy's design. But I'm glad I waited until TC9s became popular. Charles (rollo, posted above) has Pipedream line arrays he always raves about them, so that's another inspiration to trying these.
I wired my array with 23 drivers per side (basement ceiling constraints) with 8 drivers in parallel and 3 sets in series. I made a dummy driver by using an 8 ohm resistor since I would be 1 driver short of the 8x3 configuration.
That is clever idea, the extra resistor.
The forum member from diyaudio.com named wesayso, I saw you mentioned him in your post, he used insulation as a stuffing material and I wish I had. I only lined the walls with acoustic foam and think I could have gotten a few hz lower with insulation fully stuffed. Oh well, just more work for me to do later.
I'm not sure what I'm going to do about acoustic damping yet. I already have large enough volume, full .1 sf each, so I don't need full stuffing to increase apparent volume. Boosting bass electronically simulates lower Q that you would get from more stuffing anyway, so that's moot. We only need to be concerned with impedance blips that might affect FR. fluid's recent impedance plot with no stufffing looked pretty harmless to me so I'm not worried about it. I prefer minimal damping of the cone motion, to maximize transient response, so I would use only a little stuffing, if any. Lots of stuffing increases friction of the air moving through the stuffing, on the inhale and exhale. So the stuffing prevents free motion of the cone, dulling transients, robbing the feeling of life from the music. I'm not so concerned with minor impedance bumps if I have very strong electrical damping in the amp (low output impedance amp) and dsp to correct the bad FR bumps. The impedance bumps come from acoustic reflections inside the cabinet. That can only happen at wavelengths equal or smaller than the inside box dimensions. Below that freq it is just standing wave, pressure pulse, no reflections, no resonance, no impedance blip. My drivers each have their own chamber ~3" tall, so reflection wavelengths are very small, 8" is the largest and the one I'm concerned about, that makes fundamental resonance at 1700Hz. That should be easily damped with 1" FG or cotton on the reflection surfaces. The 3" vertical height of each chamber resonates at 4500Hz. I guess that's more of a concern and I should think more about that. I'll experiment with it in a mock up box. Thanks for raising that. 1/4 foam or cotton insulation should kill that enough.
I used a 3" hole saw as well but the one I was using didn't quite make the holes big enough by about 1/32" maybe 1/16". So, I had to take my dremel and sand each hole with a sanding bit to get all of the drivers to fit.
My hole saw is Milwaukee brand, it cuts a hair too big, so perfect fit for TC9, lays flat, no wobble. I did a test hole a few months ago before the main run. Lots of work cutting all those holes!
I assembled them with crimp terminals (huge time saver)
Where did you get the terminals and what sizes did you use? I've been thinking about doing that, but my audionervosa perfectionism drives me toward soldering. I always thought that a dab of silver conductivity paste like Walker SST or similar should make slide on terminals work as well as solder. What do other ANs think about this?
and slapped some ribbon stripe mahogany veneer from veneersupplies.com (best place for veneer BTW) and bam had some very nice towers. Overall build probably costs about $800.
I bookmarked that link for future reference. My build cost a little more with the more drivers, but similarly cheap. I like that!
Listening impressions: just to give you even more motivation to finish these.... best speakers I have built to this day! Once you listen to a line array you will be addicted to them for life. The absolute lack of distortion is mind blowing, at any volume.
That's awesome. I can't wait to hear mine. Part of the reason I'm trying these is cuz people said how great the bass is, and they can play loud without getting edgy. I love to play modern symphonies and big bands really loud, reminds me when I used to sit in the orchestra playing trumpet. But I'm tired of paying 10k for speakers that can handle it without distortion (they still do distort anyway - so how much do I have to pay? Hence DIY, and hence line array with huge headroom and low distortion.
Mine need big EQ down low but that may be from my room being a terrible audio environment. Around 20db is what I was working with to get +3db over flat in the bass region.
That's about right, judging from FR measurements of the uncorrected array, like wesayso. But 20dB boost is a lot of power. I think he figured he needed 250W to push his array to linear Xmax. You want headroom in the amp too, like you said. Since this is full range you don't want to listen to inexpensive class D amp playing at full power trying to play bass and treble at same time. The amp distortion rises near max power and makes the mids and treble sounds very distorted. I'm installing my arrays in a pretty small room, and in corner mounted, so there will be a lot of LF room gain. I'm going to start with
NeuroChrome Parallel-86 chip amp because I love the sound of the Mod-86 design and I already have the PCBs and chips. It makes 120W>4. My wiring will make 4 ohms load. If that's not enough power, maybe NCore 500, like Nord. Or a custom DIY amp from my local friend Sol.
I was using a inuke 3000 to drive them and was running out of headroom quick... the bass sounded so smooth with the line arrays and it's almost a mind trick hearing this clear bass coming from such small drivers. Mind range is excellent and the highs are so nice to listen to that I experience no listening fatigue whatsoever. I sometimes fall asleep when listening to these speakers for an extended period of time. I do not see myself building any more point source speakers in the future unless they are for someone else.
That's what I'm hoping for too. I don't want to notice the speakers, I don't want to hear the "details." I just want the music fully exposed for me to choose how I listen at any moment. I don't want to be held hostage to the sound quality by speakers.
However, since I was running out of headroom with so much EQ in the low end and not wanting to constantly dump all that power on the TC9 voice coils, I decided to make a pair of stereo subwoofers to handle the low end.
TC9 voice coils can handle the distributed power no problem, but 3" drivers will always have limited acoustic impedance, no matter how many in a straight line, it's still only 3" wide and the air molecules can easily get away from that small cone when it is accelerating so slowly at LF. Only large driver cone can grip the air firmly at LF. The air in the middle of big cone can't escape. So bass detail is always better with larger diameter drivers.
wesayso feels the need for subs for his HT use, maybe for more LF volume in his big room. But he said it's OK without subs for music. I think once he gets the subs playing he will like them for music too, because bass detail, slam and tonal balance at very low volumes will all be much better. Adding that bottom octave makes such a huge difference in music listening, especially at low volume, late night listening. I'm doing this to move my primary solitary deep dive listening excursions out of the main family room of the house and into a small door closable room, officially named "the weird room." I want to be able to listen to a symphony at 3am if I can't sleep, and I want to hear the bass cuz that's what it's all about. So I may end up adding subs later too. I have 3 of the 6 walls in the weird room are exterior walls, so I might do a few infinite baffle subs in there for distributed bass. But Maybe the arrays will be enough.
I mean, it's what they were designed to do... so I picked up 2 15" Dayton HF subwoofers from parts express when they were on sale and built some big sealed boxes for them. 18"x18"x23" with 3/4" mdf walls and double thick baffle for 1.5". Fully stuffed with insulation (after making that mistake with the towers). I cross them at about 200 hz with a 8db shelf filter boost and I am so glad I did. Now I have the power to blast new age songs and the only lights that come up on my amp are for the subs. The TC9s shall live a long life! I was surprised how well the stereo subs blend with the mains, I don't even realize they are there. I initially tried pairing the towers with a BIC F12 sub I have but it took away from the stereo imagining. I am not at all disappointed with this set up and have no reason to ever replace my mains again. (My subs are still unfinished but will probably receive the same Beene as the towers) I am using a minidsp 2x4 HD for processing.
Sounds like a great setup. I agree stereo subs needed for high end music playback, especially acoustic music where LF acoustic information is very much in stereo.
I assure you that you will love your Towers, whether they are in the corner or out in the open. If you have any questions, I can try to answer them, but I'm only 23 so somewhat a noob at audio but I have a good idea. I am using a minidsp 2x4 HD for processing with PEQ only. FIR is yet to come.
Thanks, I may take you up on that as I try to get mine working. You have a lot of audio knowledge for a young person, sorry don't mean to sound condescending, but it is with respect. I'm a young person too, never grew up! Do you have electronics background?
Didn't want to jack your post, but I just wanted to share how well your towers are going to turn out.
You are welcome to hijack any thread you want here at AN, that's what we're here for. Everyone has something valuable to add. There's no cliques here. All constructive posts are welcome.
Thanks again!
Rich