So what's your current (or upcoming project)


2002-01-07 6:02 pm
Current project

Four way full horn system, using,
Khorns for bass (with some eq to flatten response to 30Hz)
Rectangular tractrix midbass 100-500Hz with EVM12L
Round tractrix 500Hz-22kHz with JBL, BMS or Beyma/Fane combos.

My 5W PP amp will run the system above 100Hz (106dB sensitivity!) with a SS amp below. All crossovers will be 6dB, except perhaps the bass HPF. And it will be time aligned above 100Hz.



2001-11-24 1:24 am
i'm putting together a 3-way based on the Geers eVe II box style. with hiquphon, p13w, and ss 8555 drivers. i have them on an AR 3-way series crossover, and would like to use it, but am looking at the crossover from Murphy production's OkaraII project and add a woofer crossover. i'd like to keep it an 8 ohm load, so i may stick with the AR.
should start the cab's in ~1month, it'll be a long road as these cabs are quite involved.



2002-02-06 9:16 pm
Also 4-way horns.
Bass: exponential front loaded, 4x12" drivers TBD volume +/- 1m³
Bass-mid: exponential front loaded TBD
Mid: Visaton M300, driver Visaton DR45N
High: Visaton TL16
Xover: 24dB
Amps: 14x JLH (or Blameless depending on budget)

Design of the bass horn is ready, but not yet the details of how to make it and get it up the stairs and through the doors. Already some drivers studied, but have to find a nearby supplier. The bass-mid is a bit a problem, thinking about an 130mm Al cone driver. Maybe that one will follow when the bass is ready so I can see where to couple. With some luck can be ready to fire up this year. Then the digital filters can be tackeled. You got to have a project next year. Only problem is what when you want a 5.1 system? 5 of those??????
GALTIS a 2½ way floorstander

I am busy buikding a new 2½ way floorstander. The cabinett has two chambers, one seladet for the tweeter and midbass, and one reflexloaded for the bass. The drivers are VIFA XT25 tweeters and Scanspeak 18W/8542 mid/bass drivers.
Lukasz Fikus has designed the filters for the speakers. I first intended to use LC Audios seroell x-over but Lukasz thought his filter would be a better choice. I´ll try it to start with.

My current project is a pair of electrostatic headphones (DIY Capital Punishment Device) and an accompanying solid-state direct-drive amp. The 'phones are done, tested them with a standard amp and step-up transformer rig, sounded great. The next part of the plan is getting the amp up and running. I've got a design, based on Kevin Gilmore's omega driving amplifier. It's one crazy schematic. All solid state, and direct-drive so the amp itself swings 600 volts or so on the output.

Once this system is complete, the next project is going to be an 8 foot tall floor-standing full-range electrostatic loudspeaker pair. Hopefully, I'll be able to adapt this headphone amplifier design to drive those. Any questions or comments welcome.

- Jonathan
baddest-*** system ever

My current project is a 4 channel Leach Amp with 4 Sony Xplod subwoofers (yeah, car subs in the house, I know) and a stereo ESP 03 amp for mid, and another for trebble (horns). My next plan is to complete my 7200W (900W x 8) amp, which I will pretty much design my self, but based on a Doug Self MOSFET design with an output stage much like the Leach Superamp, and use it for bass, with 8 or more Audiobahn subs (supposedly rated 1kW RMS each, [email protected]@1m, 31mm Xmax, and only $189 each) and using my Leach amps for trebble (horns) and a couple more 900W channels, but with lower supply voltage, each driving 3 EV 10" midwoofers (300W RMS, [email protected]@1m, $190) for midrange. All the amps are water-cooled. I honestly don't know what I'm going to do with that system.

Right now I'm almost done with one Leach amp channel and am working on the cooling system and power supply, I'm done with the cooling system for the insanely big amp, and I have those 4 Sony subs hooked up to my ordinary bi-amped stereo.
Current Projects

I am currently designing a 5 channel amp build around some (maybe 10?) of those TDA7293's (have to think how much heat those things give out in a 2U case!)

Also I am prototyping a 6 channel pre-amp which is somewhere along the lines of 6 MicroControlled BoZ with some other tricks up it's sleeve (external power supply control with loop control from some plug in PRTs (temp sensor on each mosfet/power op-amp) for all my amps. Built in sub control. etc etc) Nice elctro-illuminated 4*40 LCD!

BTW i built another of those class B boards i was banging on about earlyer, runs better then the last version. was gonna make a 5 channel amp with those, but still not happy with the distortion products.
Wow some really impressive projects here!

My next project is a pair of line arrays, based off of Jim Griffin's and Rick Craig's Linus Array design. A couple of minor modifications. 2 more tweeters added to the lines, and probably a different mid-woofer. Also I may increase the height of the speaker to bring up the top of the line source a bit. Jim Griffin and Rick Craig have been great about providing information and suggestions.

After that I will need to think about a center channel to mesh with the pair. Hmmm. It will take some thought.

Re: Full-range speaka'

Bose(o) said:
I'm building a single full-range driver system using Radioshack (Fostex) 4" drivers. I'll be using a right-angle triangle cabinet and will have an exit on the bottom. I can't wait to hear it, it's looking good with only three coats of gloss-black paint. I really, really want a piano finsih on it.:D

I would like to hear more about your speaker project: What driver(FE 127?)? Is it a ML TQWT or just open pipe or vented or...?? . I am asking because I am planning to build a smal (thin) full-range driver speaker that should be supported by a 10" sub, just now I'm sitting with Martin Kings MathCad sheets for ML TQWT and they are driving me nuts. I just dont seem be able to get those graphs where I wont them. Any input/ideas would be nice.

Full-range project

I'm using a voigt pipe that will be very similar to the one on the page below. Yes, I am using the Fostex FE127 mostly because I have heard it before (used as mids in a system) and liked their dispersion of sound. I also chose the Fostex driver because my neighbour wouldn't let me get the Audax drivers (the people that I was buying from, Solen, screwed up his orders badly). So, system will only be five feet or so high so I may be lacking in the low freq's, but I'll figure out something. Here is the website that acted as my guide through my first journey into DIY'dom. "The JOKE" I'm honoured to help you.

Fostex Tower

A tower with the Fostex FF225K

This is their 8" driver without a whizzer cone so it rolls off about 10K
I found a Vifa dome unit that has a flat resonance peak from 10k to 20k up to about 96 dB which I'll use as a super tweeter.

I'll let the big driver roll off naturally and use a filter to cut off the tweeter below 9 or 10k I figure I'll get better very high end this way than trying to do the whole thing with one driver.

This Fostex driver also has a much smoother response than the
FE 208 Sigma, and has a bit more bass. Who knows how it will sound? I will I guess, when I get it made.

First Madisound has to get the FF225K in stock. They say "any day now" Maybe I'll have them help me with the super tweeter
filter too.
Tri-Amped System With Digital Crossover and Eq

With the recent discussions about FIR filters and digital crossovers, I realised such a system is very feasible, within the grasp of many DIYers. Such a system could be constructed from a moderate PC with 3 soundcards, such as those from Midiman or RME, both of whom support multiple soundcard ins one PC, with synch-aligned output and true 24bit 96kHz output.
The system will read a digital or analog input from the source (currently a SP/DIF signal from my CD player), and output the filtered and room EQed signal to the three outputs for playback.
The software is not too daunting, especially with existing software such as the performance libraries from and looking at existing code such as BruteFIR (Linux only though)

The nice thing is it is scalable. It would be possible to start with a single analog soundcard and amplifier, then as time and money permits, add extra Amps and drive them from a standard active crossover, and then in the future add extra digital out soundcards and DAC's etc. It would be easy (and desiable) to have the computer in a seperate room, as long as the digital signals can be driven along the cables, it should work fine. I can see myself building line drivers for the spdif signals.

Of course, it will all be in vain if the analog equipment isn't up to spec, so it's going to be some form of Pass amplification for the Mid's and High's, and something class AB on the Bass. And of course the power supply will be my 2x 2.9kW switchmode rectifiers. (How am I going to get rid of the heat of 4 channels of SE Class A amplification, Heatsinks, Water cooling, Fans, wife acceptance factor, arrrgggghhhh!)

Cheers, Adrian

Bill F.

2001-11-15 5:25 pm

The "Auction Special"

Thanks to a too-good-to-pass-up internet auction, I've got 25 car audio bass drivers from 10 to 18 inches (mostly 15s) and two electronic crossover units with variable boost at 40 Hz. What's a DIYer to do?

Build a big ol' tri-amped dipole/infinite-baffle system, that's what.

I'm going to slap together two folded dipole bass baffles, ala Linkwitz, and load them with 4 15" Kicker sub drivers each. Just a touch of inline resistance will bring their total Q to 0.5--transient perfect, critically damped. I'll lowpass 'em with the electronic crossovers and equalize the dipole rolloff with the bass boost. Tweaked just so, they'll be flat to 40Hz. with a steep rolloff below. Piggybacking the crossovers will yield a 4th-order lowpass at 200Hz.

On top of the dipole bass cabs, I'm shopping for coaxials, like a set of 12" Tannoy golds, if I can get them, or maybe I'll have to settle for the Selenium coax from Parts Express. It's hard to argue with the transient and polar response benefits of a coaxial. Staying true to the theme, I'll run the coaxials atop the bass cabs in dipole baffles defining a rolloff point that compliments the bass dipole arrays.

Dipoles are known for bass quality, not quantity or depth. For room locking, pressure-cooker sub bass below 40Hz, I'm going to have to get medieval on my living room. What I plan to do is take four more of those 15" Kicker bass drivers and put them in an infinite baffle, for a (linear) displacement of 225 cubic inches per cycle.

I'll fab a manifold with cutouts on four sides, mount the drivers, and attach it between floor joists in the crawlspace under my living room, firing up through a large floor register. The opposed mounting scheme should cancel most of the manifold vibration. Again, with a little resistance, the infinite baffle can be dialed in to a Q of 0.5. With a 40 Hz. lowpass, response models flat to 22 Hz. and only about 8dB down at 10 Hz. while efficiency hovers around 97 dB/W. In my living room, this will actually be a rising response, so I'll probably end up rolling off the lower end to get flat response.

Complete the refinement of my home system:

Low (sub) : 6th order bandpass with Ciare 15"
MidLow : closed labyrinth with Focal 5k515
Mid : Dynaudio D54AF
High : Dynaudio D21AF

All-Passive x-over 1st or 2nd order (depending on the speaker) + compensations.

The speaker is done since January, but now is the typical time of the neverending small tweaks (increase a bit the male voice range, trim a bit down the upper mid etc.). This will continue until either I will be fed up or somebody will set fire to the whole basement. Unlikely that I will be 100% satisfied, it's part of the game!

Next I'm going to build for a friend a small/thin/tall 3 ways (Ciare 8" in QB3 reflex, 4" ScanSpeak mid and 19mm ScanSpeak tw) shaped more or less like an inverted flute glass.
X-over will be 2nd order passive, but this is only the first draft, we'll see (hear) how it works once the thing is done.