Active subwoofers usually have a mains powered plate amplifier - perhaps this is what the child touched.
Yessss. Seems to me that during this century of technological advances from the Audion to arduino, nothing has been learned. And someone had returned to the transformerless AA5 regarding safety to the user.
Hi, I am very slow in my diy cause i dilly help a very old personn daily and but few minutes here and there left here to write posts and sleep hours i more spenpt few times at reading also my others hobbies and sleep.
BUT i want to have fun towarsd a monkey coffin, maybe more tree heigth, with the faital 12pr360 and a 6" + 1" CD/horn
or direct two way around 900 to 1200 hz high pass with ST260 horn with tests with the mid ope as the back of the compressiçon driver, being perhaps in a compression
Sorry if this has been asked before.
What is the length of the port? I see You made some cutout but that is not critical I belive?
What is the length of the port? I see You made some cutout but that is not critical I belive?
I forgot that, it's extremely important. 4" diameter, length ~12 inches. Do not skimp on port diameter. I used a flared Precision Port from Parts Express. It had to be modified (cut on one edge on the inside lip) to fit. Tuning should be between 35-45Hz, my goal was 40.
The Bitches Brew was always a cool novelty to me. Another flavor of perfect with clever flair and simplicity in mind. This, on the other hand, is actually damn tempting. Something about putting down a few grand to find out if someone else's speakers are truly "endgame" is a difficult endeavor, but I think these have absolutely hit a value mark that's tough to beat. Even with the DSP processor, it's under $1000 and most parts are reusable if upgrade-itis comes calling. Really nice work, again.
Hybrid OBs: I have plans to create a speaker system that combines Joseph Crowe’s ES290 biradial horn with OB lower midrange / bass using multiple AE Dipole 12 woofers. Fostex T925A bullet tweeters will handle from 6 or 7khz and up.
I hosted a listening party at a hotel with the Flanagangsters for 30+ people. I arranged chairs in a large 3/4 semicircle as you can see here, and stereo imaging was great for every single person. This is always the case with Constant Directivity Dipoles. The chair nearest the speaker is only a few feet away but since it's 75 degrees off axis, the SPL is the same as it is in the usual "sweet spot." You can stand next to the left speaker and hear the right speaker perfectly well and get a stable stereo image.
It's one of the reasons I feel radiation pattern separates the men from the boys in speaker design. If you get true Constant Directivity across the entire band (including rear radiation not just front!) the reflections from the room match the direct sound and you get the expansive Open Baffle sound as well as fantastic imaging for everyone. @dawa @Studley @D1sco @diyiggy @tlarwa @Juhazi @jjasniew @wonderfulaudio @LewinskiH01 @CharlieLaub Also, 2 Adcom GFA 535s (60W/channel) had no problem filling the room with sound. If we'd wanted to crank it super loud with heavy bass, the speakers would handle a 200-300W amp just fine.
It's one of the reasons I feel radiation pattern separates the men from the boys in speaker design. If you get true Constant Directivity across the entire band (including rear radiation not just front!) the reflections from the room match the direct sound and you get the expansive Open Baffle sound as well as fantastic imaging for everyone. @dawa @Studley @D1sco @diyiggy @tlarwa @Juhazi @jjasniew @wonderfulaudio @LewinskiH01 @CharlieLaub Also, 2 Adcom GFA 535s (60W/channel) had no problem filling the room with sound. If we'd wanted to crank it super loud with heavy bass, the speakers would handle a 200-300W amp just fine.
The Flanagangsters
A Heretical Reflex+Open Baffle Hybrid
Constant Directivity, 96dB SPL, 300 Watts, 35Hz-20KHz
Crafted from Live Edge Wood
(re-posted from https://www.diyaudio.com/community/threads/ultimate-open-baffle-gallery.123512/post-7216744)
This design is Bass Reflex below 100Hz and Open Baffle above 100Hz, using one 12” woofer as a Point Source bass and the other as a Dipole Midrange. It combines the stage, imaging and open sound of Open Baffle with the bass and power output of a reflex.
Is this heresy? To a Dipole purist, undoubtedly so. But it delivers a huge un-boxy stereo image with the bass punch of a traditional ported design.
I’m proud of the polar response spectrum, it exhibits excellent Constant Directivity from 150Hz to 20KHz; it has -6dB points at about 45 degrees off axis, very consistently from 200Hz on up. Notice that even at 20KHz the pattern doesn't narrow much; this is because of the waveguide:
Frequency response at 0, 15, 30, 45, 60, 75 and 90 degrees off axis:
1/6 octave curve at 0 15 30 45 60 75 degrees:
The above measurement doesn’t capture the bass output of the port. Here is the measured response of the port + lower woofer.
I made these for my friend Jeremy Flanagan who loved the Bitches Brew Live Edge Dipoles but needed something much smaller and more economical. These deliver 80% of the performance for 20% of the cost. I wanted these to have the luxurious room-filling sound of Open Baffles but be capable of functioning as “party speakers” when called upon to do so.
The woofers are Dayton PA310s with 96dB SPL sensitivity and 3-inch voice coils. The lower woofer operates from 35Hz to 100Hz in a 40-liter reflex tuned to 42Hz. The upper woofer operates as a midrange from 100Hz to 2KHz in open baffle configuration.
Front tweeter: Audax TW034X0 34mm classic soft domes matched to Troels Graveson waveguides. (http://www.troelsgravesen.dk)
Rear tweeter: Peerless by Tymphany BC25SC08-04 1" Silk Dome Neodymium Tweeter
Crossover & Digital Signal Processing is handled by a MiniDSP 2x4HD with FIR time correction for linear phase. Configuration files: https://tinyurl.com/flanagangsterfiles
Some readers will be puzzled as to my unorthodox choice of using two identical 12” woofers, one as a midrange and the other for bass. I chose the Dayton PA310 for its high sensitivity and for its suitability for a DSP assisted reflex alignment in a small box, and because of its ultra-smooth midrange requiring very little help from the crossover.
The woofer has 5mm Xmax. This would fall far short of what’s necessary in an Open Baffle, but 5mm is plenty in a reflex, especially since the DSP filters out frequencies below 35Hz using a high-Q shelf filter. There is surprisingly little excursion at high volumes, and plus it doubles as an excellent midrange. And even with the small baffle size, the 12” dipole midrange effectively operates down to 100Hz.
This is the simulated reflex alignment of the woofer:
Below is the MiniDSP EQ correction curve for the woofer – notice the 9dB of bass boost at 40Hz which complements the above curve and renders the system flat to 35Hz:
Everyone is going to ask how the Dipole-Reflex hybrid sounds. Well, it sounds like normal low bass of course but with the very low crossover point of 100Hz to full dipole midrange, these sound more like dipoles than box speakers. They most emphatically do not sound “boxy,” and they have that huge, wide, lush imaging that Open Baffle designs are famous for.
NOTE: I used Precision Port 4” diameter ports (large diameter ports are absolutely essential to prevent power compression and chuffing). Since there’s so little room on the inside of the smallish box, I had to cut the inside port flare with a jigsaw to leave enough space to install the bottom woofer. Port length is 12 inches which tunes it to 42Hz.
The 100Hz crossover is a 6dB/octave "series" configuration instead of the conventional parallel. It has better impedance interactions. This curve shows the drive signal of the 12" midrange, which is much steeper below 100Hz than a standard parallel design would be:
The blue curve is the input signal to the whole system, and the green curve is the voltage measured at the terminals of the midrange. The impedance curve of the woofer is being turned "upside down" and being impressed on the midrange. This is reducing the output of the midrange at 20Hz and 60Hz, which is desirable. A standard parallel network would impress the midrange's impedance curve "right side up" on the response, which would be undesirable.
Schematic:
The LC circuit on the woofers is a 100Hz "series style" crossover. The capacitor on the TW034X0 is just for protection; the 10uF capacitor on the Peerless tweeter rolls it off at about 3K because I have concerns about driving it at lower frequencies. The rest of the crossover action is in the DSP.
Seth's CAD drawing:
My original sketch:
The tweeter, an Audax TW034X0, is one of the longest-in-production tweeters in existence. First introduced in the late 1970s, it’s used in the BBC LS5/9 and many other designs. It’s a famous mid-tweeter and when used conventionally (without waveguide) it’s a solid competent driver that gets slightly beamy in the high end, with 93dB sensitivity and response up to 16KHz.
However, when used with the Troels Graveson waveguide, sensitivity jumps to ~98dB and is no longer beamy in the top octave. The waveguide renders it a true Constant Directivity device. I use the DSP crossover to 1) establish a 2000Hz cutoff, 2) apply FIR filters for linear phase, and 3) extend the high end out to 20KHz.
The Audax 34mm tweeter has a round, soft, mellow sound with no listener fatigue whatsoever. It won’t appeal to people who prefer the etched hyper-detailed Titanium, Beryllium and Aluminum domes, but it certainly does not lack clarity. Especially with the waveguide, it has excellent dynamics. It is able to keep up with a high sensitivity 12” woofer, at least for aggressive domestic applications. (I wouldn't actually use these in a PA system, you'd probably blow out the tweeters.)
Open Baffle speakers that radiate from both sides via woofers but have tweeters only on the front sound “wrong” to my ears. I prefer true dipole behavior across the whole range, so I added a Peerless 1” dome tweeter with waveguide on the back. This is the frequency response on the back side, measured 45 degrees off axis:
NOTE: The tweeters are wired in parallel and the impedance dips to 2.6 ohms. Since sensitivity is around 98dB and since most music doesn't have large power requirements above 2KHz this won't be a problem for most amps. But this could be an issue for some people.
Impedance of woofer section is a breezy 8 ohms, minimum Z is 5.7. You can see the 42Hz port tuning frequency as well:
Tweeter section below is about 3 ohms:
I feel these do successfully achieve their objective of: Delivering most of the power and impact of the Bitches Brew Dipoles, without the expensive high-end drivers and huge size.
The Constant Directivity sound pattern means every seat in the house is excellent. You can stand right next to the right speaker and hear the left across the room with an intact stereo image. The DSP assisted reflex means with a 200+ watt amp and 96dB, these will play at loud party levels without stress or fatigue. A few months ago, I hosted a listening party at a hotel for 40 people and they easily filled a medium sized hotel ballroom with sound.
At low frequencies the DSP delivers a 6-9dB boost between 35 and 55Hz, so at low frequencies the SPL is 87-90dB not 96dB. I greatly prefer that to a speaker that requires no bass boost but is 87dB across the whole spectrum. The 100Hz crossover means that the midrange 12” driver is never even going to move visibly so it has very low distortion regardless of what’s happening in the bass registers.
The cabinets were built by Seth Cothron (@studio38designs) and the 1.5” thick front baffles provide more than enough rigidity to get the job done.
Here are the DSP configuration files: https://tinyurl.com/flanagangsterfiles
These have great stereo imaging everywhere in the room, tremendous dynamic range, and achieve the advantages of Dipole + Reflex with almost none of the disadvantages. Distortion is incredibly low and they have a creamy midrange and very non-fatiguing high end that's easy on your ears.
I would love to hear from others who create Open Baffle hybrids with other enclosure types. Acoustic suspension is possible, perhaps even TLs and horns.
What kind of wood is that and where can you get it?
There are actually 2 versions of these speakers if you look very closely at the photos (long story). The one pictured above in the hotel is Beech. You'll see Poplar in some other photos. Got it from Schroeder Hardwoods, Harvey IL.
Also I've bought wood from Big Red Sawmill in Palmyra Nebraska. It's really fun to go to these lumberyards and pick out big slabs of live edge wood, they have huge inventories with all kinds of possibilities.
Were you able to use a regular router etc or did it require using something more serious.