| Project by ferstler | posted 392 days ago | 456 views | 0 times favorited | 7 comments |  |
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The left and right speakers in this system were built entirely by me. (The center speaker in the room picture is a hybrid, with the tweeter/mid array being an NHT speaker, but with the enclosure, a special crossover network, and bottom-mounted woofer added by me.) As shown in the uncovered close ujp of one of the systems, the stacked tweeter drivers in the left and right units are Allison RDL models, and the 6.5-inch woofer at the bottom also an Allison unit (and the same design as the bottom-mounted one in the hybrid center). The silver-framed, over/under pair of midrange drivers are very good Chinese TB Systems units. They are 4.5 inchers with fixed phase plugs (also silver colored) to broaden dispersion. The two speaker systems can be biamped (and are biamped in this hookup), and each has two separate, second-order crossover networks (with polypropylene capacitors and bistable resistors to protect the drivers) that facilitate being driven that way.
The cabinet top, bottom, and sides are well-finished, solidly braced internally .75-inch pine, stained and coated with urethane. The front and back are .75-inch mdf, painted black. The upper and lower sections of the enclosure are acoustically isolated, with the bottom stuffed with fiberglass fill and the top stuffed with poyester fill. The grill (removed in the individual photo) has a frame made from half of a broom handle, cut in half again to make two quarter sections (the work was done with a band saw), with small dowels as crosspieces and fine mesh stretched over and glued in place. Each speaker weighs 45 poiunds and is roughly 4 feet high. The speakers are driven by two stereo amps, adding up to about 190 watts per channel. (The hybrid center is powered by a single 110-watt amp. The control is from a Yamaha processor and the full system has 7 satellite channels and one subwoofer channel. A Rane equalizer flattens the response of the three front speakers to within 2 dB from 90 Hz to 12.5 kHz.
The woofers of the systems (including the hybrid center) are not powerful enough to handle serious home-theater bass, so the speakers are configured to act as satellites, with a big Hsu subwoofer (shown right of center in the room photo) handling the bass between 90 and 20 Hz. Note: the TV in the center is a 1080p 56 incher.
I have authored two books on home theater, written two more dealing with record reviews, and helped to write and edit The 2005 edition of The Encyclopedia of Recorded Sound. I have also authored more than 200 audio-magazine articles, including product reviews. The left and right speakers in the picture (and also the closer shot of the one without the grill) are a match for any high-end speakers I have auditioned and reviewed over the past decades.
Howard Ferstler
7 comments so far
mtnwild
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1979 posts in 405 days
posted 392 days ago
Bear’y nice work, bet it sounds great. Looks like a packed house for the show.
-- mtnwild (Jack), It's not what you see, it's how you see it.
ferstler
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136 posts in 398 days
posted 391 days ago
The bear collection belongs to my wife. Actually, their stuffiness works to dampen midrange and treble reflections somewhat, not a bad idea as long as it does not get out of hand.
Howard Ferstler
thetimberkid
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1944 posts in 581 days
posted 390 days ago
Great system!
Thanks for the post
Callum
-- For wood working podcasts with a twist check out http://thetimberkid.com/
RCT
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15 posts in 629 days
posted 390 days ago
Glad to see another speaker builder here
Always loved Allisons
Nice build and the brilliance of using the
bares for room reflection control
Vary nice
RCT
-- "Ya but what does he know anyhow?"
ferstler
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136 posts in 398 days
posted 384 days ago
One way I check the voicing of the speakers I have built is to make use of an AudioControl SA-3051 real-time analyzer. The unit includes a 20-second averaging feature and I basically move my measurement microphone slowly over a roughly 1×1x5 foot area near seated ear height at the listening couch in my main AV room while the RTA averages the speaker-generated energy hitting the microphone over that area. The energy source used is decorrolated pink noise, which is equal energy per octave. The decorrolation helps to prevent coherent reinforcement in the bass, which allows the unit to better average total power. This technique minimizes hot spots and sanding-wave artifacts and gives a decent idea of the power input from a speaker (or stereo pair of speakers) into the listening room. A multitude of multi-angled and averaged measurements in an anechoic chamber would be better, but the technique I use is actually quite good and correlates decently with some of the anechoic work I have seen with speakers I have reviewed.
Howard Ferstler
Woodchuck1957
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950 posts in 642 days
posted 327 days ago
Nice looking speakers, what components are you useing ? Amp ? Preamp ? Turntable ?
ferstler
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136 posts in 398 days
posted 327 days ago
The amp is a Yamaha DSP-A1 integrated unit, with severn channels of amplification and an extensive digital surround ability. Its on-board power amps drive the woofers of the left and right speakers and an outboard AudioSource Amp One powers the mid/tweeter arrays. A Rane THX-22 equalizer shapes the curves to +/- 1.5 dB from 90 Hz on up to 12.5 kHz. Below 90 Hz the bass is handled by an outboard Hsu VTF-3 (MK3) subwoofer that is itself equalized by an AudioControl C-131. This sub is powerful, flat, and strong to below 20 Hz.
I also have an AudioControl “Phase-Coupled Activator” in the system. I use it to “synthesize” ultra-low bass with rock music and older movies. The older movies come from a vintage Pioneer laserdisc player that has an analog output. You cannot use the Activator with the DVD player, because its output is digital and the Activator is an analog device.
This is a “seven-channel” system, with two modified Radio Shack speakers in the upper right and upper left front corners, and with a pair of Allison Model Four units further back operating as basic surround speakers. The Yamaha integrated amp can control all of them.
There is no turntable in this system at all. I sold off all of my LP records (about 1,000 of them, most of which were classical) back in 1985. I saw the handwriting on the wall for analog LP audio way back then.
Note that this is my “small” system. I have pictures of my larger one also on this site, where I made a custom center speaker to complement my two Allison IC-20 main speakers. That other system uses a Yamaha RX-Z1 receiver, in combination with a vintage Carver M500 amp. It also has big Velodyne and SVS subs.
Howard Ferstler