No respect, but it should be obvious. Anything which modifies the sound, is infidelous (if there is such a word).
My suspicion is that resonant bits in the system can be heard, even if they appear as minor burps on the freq response. That's esp. so at the acoustic end where various triggers can set them ringing.
Due to the idiotic situation where our drivers have their natural resonance within the desired low freq passband, it is troublesome to address. But for sure, better to avoid resonances than to cultivate them, as some builders prefer.
B.
I have a hunch that it's frequency dependent. For instance, data-bass published measurements of a DTS-10 tapped horn, and the waterfall plots look HORRENDOUS. But tapped horns don't sound bad to me at all.
OTOH, ribbon tweeters generally sound "clean" to me, and they have very good waterfall plots. So I think the aversion to resonances is frequency dependent; basically the lower in frequency, the less obnoxious they are.
The wave cannon is essentially resonant chamber tuned to a certain range of frequencies. I imagine that it subjectively sounds like something for reproducing whale songs. Not what I'm after. Plus the big sonotubes aren't easy to get.
Which makes me wonder if two or more smaller ones were mated together and designed to overlap right if they could cover a broader range of frequencies. Some cheaper 8" drivers could be used. But it becomes more complex at this point.
I like the whole "depth charge" thing. I'm thinking put some 8" drivers on opposite ends of a sealed tube. They will start to couple and produce +3 db of tight bass below about 50 hz. This idea of subwoofer arrays makes sense to me.
I agree with Ben to some degree. I've had the best luck with sealed bass and it maybe just simply that there are so many variables especially with the drivers themselves that its tough to get more resonant designs right, at least in a DIY environment. The measurements can be a challenge.
Which makes me wonder if two or more smaller ones were mated together and designed to overlap right if they could cover a broader range of frequencies. Some cheaper 8" drivers could be used. But it becomes more complex at this point.
I like the whole "depth charge" thing. I'm thinking put some 8" drivers on opposite ends of a sealed tube. They will start to couple and produce +3 db of tight bass below about 50 hz. This idea of subwoofer arrays makes sense to me.
I agree with Ben to some degree. I've had the best luck with sealed bass and it maybe just simply that there are so many variables especially with the drivers themselves that its tough to get more resonant designs right, at least in a DIY environment. The measurements can be a challenge.
For large sonotube, find a concrete and construction supply company. It's a small specialty place, not home depot. There is one in a neighboring town that stocks up to 30". The contractors everywhere have to have a source in order to make large footings, light pole bases, etc. Also check distributors for "cemetube". It's a plastic version made in Wisconsin up to 30". Craig
pipe organ subwoofer.
take one pipe for each note to be produced.
load with drivers
wire all up together.
vola.
now say we have a line of pipes.
and we hit a 30hz tone. one would sound, prehaps another would only sound harmonics. some wouldnt really sound at all. raise the pitch and the one to the side would sound more and so on.
a pipe with a woofer is a instrament in itself. is it truelly possable to get a even spread of frequancy from one dimentioned, transmision line or tapped horn or transflex or bass reflex,
as far as I know. we do our best but sorta having the peek volume of the responce of the driver and its resoundant frequancy somewhere between the tunning of the pipe/whatever resonater and its two out putting sides, but is it actuallisable in real life to have a uniform frequancy responce from say 20 to 60 or 25 to 75 or 30 to 100 for example from just one single cabinet, when the size of the cabinets and drivers we use differ is size like the pipes or the organ. or is any frequancy responce of any harmonic resonator governed by the size of the 'pipe'
take one pipe for each note to be produced.
load with drivers
wire all up together.
vola.
now say we have a line of pipes.
and we hit a 30hz tone. one would sound, prehaps another would only sound harmonics. some wouldnt really sound at all. raise the pitch and the one to the side would sound more and so on.
a pipe with a woofer is a instrament in itself. is it truelly possable to get a even spread of frequancy from one dimentioned, transmision line or tapped horn or transflex or bass reflex,
as far as I know. we do our best but sorta having the peek volume of the responce of the driver and its resoundant frequancy somewhere between the tunning of the pipe/whatever resonater and its two out putting sides, but is it actuallisable in real life to have a uniform frequancy responce from say 20 to 60 or 25 to 75 or 30 to 100 for example from just one single cabinet, when the size of the cabinets and drivers we use differ is size like the pipes or the organ. or is any frequancy responce of any harmonic resonator governed by the size of the 'pipe'
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Basic pipe/horns are ~two octave devices, though one can cheat a bit with 6th order alignments and in the case of the BAWC can somewhat fill in its 3rd harmonic dip per DJK by simply folding it into a 1/2 square antenna alignment, smoothing/extending its HF response an extra half octave [intentionally overly descriptive design routine post in the hope of never needing to explain it again, especially now that DJK has 'left the building']: https://www.diyaudio.com/forums/subwoofers/9501-acoustic-wave-canon-6.html#post1175482
GM
GM
Is that what this is?
2 paths 2 drivers, it says are identical lengths but the drivers are each situated at a different point along the length of the transmission line
if im reading correctly. (I was not slots ment ports and the design uses 2 sizes, ulthough the concept is simuler) Has anyone tryed to simulate 2 combined slightly different transmissionlines and summed the frequancy responce/output of both, im interested, it must be something to do with yelding a smoother or extended responce by having the two tunings to fill in the null that could be present with just the one, as a harmonic resonater by nature has the fundemental wave in phase most and,
I think its the 1/4 or half wave first harmonic?
and the responce we use is between these two nodes.
I do not know if with a transmission line as mentioned in my before post, does actually acheve a flat responce between the fundemental and the, ...im not sure how to word,
but it is bassically the idea that a pipe will have its harmonics and somehow using two in situe could fill in the nulls and diminish the peeks, I can visulise what I mean but will need further research/insight.
(Quote)
I own a pair of Hegeman Professional Loudspeakers, the bass portion of which is the exact design Hegeman allowed Shahinian to build and sell as the Contra Bombarde subwoofers. This fact is verified both by Shahinian's sales literature (quoted below) and a comparison between my speakers and a pair of Contra Bombarde I had the pleasure of inspecting.
"The conceptual creation of A. Stewart Hegeman, formerly the bass portion of a loudspeaker known for 20 years as the Hegeman Professional...This Shahinian orchestration of Hegeman's manuscript exists for us to enjoy. It is the most meticulous execution of this fabled classic..."
The design does use two 8" drivers, and they are loaded by two transmission lines (Hegeman described them as a "split, slot loaded conical horn"). But both TLs/Horns are symmetrical (same length, same everything), except for the "slots" that terminate them (each TL is terminated by two slots). One line has larger slots than the other.
More importantly, only the front of the 8" drivers fire into the TLs/horns. The back of the drivers just play into a rear chamber, which is stuffed with fiberglass insulation.
I have no idea where Skip Weshner got the idea that the front and back of the drivers each were each loaded by separate TLs/Horns, or that the TLs/Horns were precisely tuned to compliment each other, but that is complete bologna.
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How to Get Better Bass Part 7 - Audiophile Review
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Its certainly possible to build horn subwoofers, but it doesn't seem all that practical for a home environment. Horns are more useful in getting bass from a mid or full range driver. It really depends on what you listen to and how tight of a sound you need. Horn subs might be a good choice for something like a stadium.
In a typical room you have room gain, so adjustability is key.
In a typical room you have room gain, so adjustability is key.
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Depends; a corner horn need only have a ~ room friendly 1/8 mouth area = ~4 ft^2/40 Hz, though with the advent of the various generally easier to build so called tapped TLs, horns and super powerful/high displacement woofers it's moot for woofer systems where the XO point will be < ~120 - 250 Hz depending on type, install.
GM
GM
I've heard it said and accept that decay is mathematically related to frequency response (the whole spectral decay plot debate). So then if a horn or bass reflex system has a particular response then shouldn't it sound exactly the same as a sealed with the same response?
Not trying to hijack the thread but seems related to the subject of "resonancy bass".
I had a Contrabombarde in its day - it was one of a few things heavy enough (and perhaps as no driver showed) not to be stolen from my house which was 50 feet from the County Jail in the 1980's. The two exits on the cabinet's bottom didn't have a lot of area. (maybe 14sq.in. per exit ?? -does that sound ballpark ?) I never got the back chamber door off but assume it ran two custom Oaktron 8". Quite a bit of midrange could be heard at the exits when run without crossover and normally ran with a Belles A amp and Dahquist crossover to a pair of MG1 imp. (-can't remember if it could excite a larger room later on as well as a cheap diy 12" driver BP4 ?)
With regards to horn subwoofer augmenting horn systems - is there a magical downsizing of system which will preserve "good horn sound" ? (whatever that may really be) - can one use a TH/reflex/sealed/TL sub to augment horns working 135Hz upwards without subjective penalty? - is it better to have horn loading down to a cello's low end (and male voice fundamentals) at ~70Hz? What about the directivity of midbass horns on their low and high ends?
With regards to horn subwoofer augmenting horn systems - is there a magical downsizing of system which will preserve "good horn sound" ? (whatever that may really be) - can one use a TH/reflex/sealed/TL sub to augment horns working 135Hz upwards without subjective penalty? - is it better to have horn loading down to a cello's low end (and male voice fundamentals) at ~70Hz? What about the directivity of midbass horns on their low and high ends?
That's sort of what I was getting at with my question to GM, what exactly makes for the sluggish resonancy type sound we associate with horns?
do some folded horns possess resonances which would not appear in their unfolded counterparts ? Can it measure well yet sound colored? (RCA-Fan says a good folded midbass horn is one which sounds natural on cello and male voices - no "chestyness")
Well, if the reflex, horn is designed/damped to match the sealed's Qtc and both the sealed's, reflex's baffle area = horn mouth area and power is limited to below the worst case onset of driver distortion, then BW limited to below the driver's upper mass corner [Fhm] they should in theory sound the same, but the horn must also be 'critically damped', i.e. all internal and mouth reflections back to the throat must be similarly damped to ensure there's no perceived 'ringing'/'honk' .
As you can see, a proper comparison mostly negates a compression horn's superior performance attributes and why until fairly recently, LF horns tended to be large sealed/whatever cabs with a short horn designed to amplify/extend its mid bass, mids, lower HF to match up to a horn driver's designed in break-up modes BW to get up to as much as 5 octaves of usable BW.
Fhm = 2*Fs/Qts'
Qts' = Qts + any added series resistance [Rs]: mh-audio.nl - Home
GM
In the case of vintage expo FLH's, the mouth area of the HF horn set the ~mids throat area, which in turn its mouth area ~set the bass horn's throat area as opposed to close matching of polar responses nowadays.
IME, which started with proven Altec mass loaded [vented] compound horns [A7, A4 Vott] and later cutting off the A4's back box and compression loading them to blend to a 'sub' system that nowadays is called a ML-TQWT [vented inverse tapered TQWT], all corner loaded and baffled such that these 'subs' were effectively 6th order @ 120 Hz/2nd order, its performance was 'to die for' compared to the original A4s [both systems tuned to 35 Hz] and was kind of shocked that when I retuned the 'subs' to 20 Hz and later still at 14 Hz they actually seemed to improve WRT 'pace, rhythm and timing' [PRaT]', which I now know is due mostly to increasingly over-damping them as they were initially critically damped ['click' test] and to some extent from room interaction, though with no budget to measure such things back in the '70s, no clue how good/bad this system really was or even if I would be pleased 'enough' with it today after being spoiled by DSL's L-C-R SH50 + dual DTS20 LFE [I forget what the surrounds were] 5.2 cinema system I auditioned at Gainesville some years ago now.
Anyway, over time me and many others have found that basically any alignment can blend to horns if properly damped to get the desired PRaT, just some take up more room and/or require [much] more power than others to meet the desired level matching.
Obviously, the goal would be TL/horn loaded down to at least 16 Hz or at least a truncated horn that loads the XO's overlapping BW to 'bridge'/'taper down' from horns to BRs/whatever, but once the room's [boundary] gain, size is factored in it becomes more about controlling directivity, with Dr. Geddes' recommending 1 kHz IIRC and me and a few others preferring 350-500 Hz and anyone using vintage Altec, JBL, etc., small cinema/PA will say 150-200 Hz even though these types were typically only rated 'flat' from ~250 or 500-2500 Hz to 'blast' vocals through a perforated screen or over long distances in PA apps, so no real consensus AFAIK.
WRT directivity, the theoretical ideal AFAIK is no [early] reflections till past the ears and a diffuse sound field behind, which done right in a typical room requires mass quantities of various type dampers if the speakers aren't designed to meet the needs of the app.
GM
Ah, yes. Exactly true if the "response" was the same.
The error arises when people mistake the plot which is labeled "Frequency Response" for the whole picture of the response. Trying to characterize the "response" using just a single snap-shot is sort of like the parable of the six blind observers and the elephant*.
That error is compounded when builders adhere in believing that the FR produced by a simulation program tells the whole story of the sound performance.
B.
* just for starters, Toole used the spin-o-rama which at least looked at 3D performance. But really it is the dynamic performance (such as playing pulses and inertial behaviour) that is needed too. BTW, inertial behaviour is where BRs and THs look atrocious and true horns look good.
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