From my pre T/S horn design ROTs that worked so well for me I never got around to actually building any T/S designs to compare, i.e. the pioneer's tuning the chamber the mean between throat - mouth frequencies.
After DIYing a pair of 825 cabs I decided to never waste my time again on woofer horns after the local Altec distributor/in house designer pointed out/demo'd for me using an 825 horn expo vs a one bend version that WRT expo, as long as the joints were in octave spreads it was sufficient and of course you can break it down finer and/or nowadays do comparisons in HR or similar if skeptical and/or do GD/whatever comparisons I didn't know about and apparently didn't hear either.
My midbass solution is a folded exponential horn with a Fostex/ACR 8 inch fullrange driver. 80- 400hz with gradual roll off in the higher freqs. If you don't need earsplitting sound pressure, you can get away with the small x-max and light membrane.
@Horneydude
even tho I'm out of the game- I'd like details (if they can be shared) on the 8" Fostex driver folded horn.fwiw FE206en works well in a Karlson 12.
If you want less than 30" depth I doubt that it would work properly wrt the constraints you mentioned. But just use a program like Hornresp and simulate a round tractrix horn for clean 100Hz by providing the throat area you intend. Later you could transform the round areas to quadratic.
here's what my scaled University Classic did with a low Q Eminence 10". IIRC its around 16" deep
I get a pretty good drum sound from two K3 plus my Kube12 on a $40 Kinter 3118 2.1 amp
.
A Kube15 with solid stage might make a compact midbass at 20-21" height as long s there some real drive power.
I get a pretty good drum sound from two K3 plus my Kube12 on a $40 Kinter 3118 2.1 amp
.
A Kube15 with solid stage might make a compact midbass at 20-21" height as long s there some real drive power.
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Well, the driver is a FE204, no longer in production. In my horn they survived for a long time already, and I do abuse them now and then ;-) Horn length about 106 cm expo. Mouth 1800cm2 and bifurcated, so there are less problems with higher freqs (at least that was the intention). I posted a drawing on this forum lately.
Bottom line is that my solution involved a light membrane full range driver with powerful magnet, so the nuance/resolution in the midbass is preserved and with good sensitivity. At least that was the intention and I guess I succeeded because that horn is the only part of my system that I do not feel I need to replace, only maybe for a better constructed one, with smoother 3d printed reflectors f.e. I know there once was a bass version of a Lowter full range driver; I would love to try them in my horn.
Those specs look good with FE206EN , St= 0.5 Sd, and 5 or 6 liter back chamber. What are the outside dimensions of the box? Do the horn mouths meet? (That's a long path for a little "W" box - if "W") "10 watts" input is around 113dB at 105Hz.
Since that's a success - whats a reasonable midhorn solution to match?
Since that's a success - whats a reasonable midhorn solution to match?
The inner dimensions are 30cm high, 60 cm wide and 67cm deep. There is a back- and compression chamber. Placement on the floor (helps with the low end) near the side wall, but not close to the back wall. The mid/high horn is Le'Cleach.
Very interesting discussion.
I’ve only used pre-fabricated horn solutions for any length of time.
I started with a used pair of Oris 200 horns and a variety of “fullrange” drivers. They are supposed to be basically a short Tractrix profile horn/waveguide.
There were a few reasons I moved on from them. They got knocked over and damaged…but I had already come to odds with the “head in a vise” directivity.
I wanted to move on to try multi-way horns and realized quickly that the “mid-bass” solution seemed like the most difficult problem to solve due to some of the basic issues being wrestled with here. Finding the space is not easy…and I currently have much less than the OP.
I just barely learned enough Hornresp to model a few ideas.
One of them was to try the 8pe21 on the Oris 200…thinking “hey, I have it” and I’d repair it. I just took mouth, length and throat measurements (approx. 21x12x7”) and worked backwards assuming a Tractrix profile.
It actually didn’t look that bad from about 200-800Hz…once you got the back chamber small enough. Although I asked myself how much of that is due to the Oris?
I got more out of the model by extending the length of the horn with an adapter and shrinking the throat to add compression. Which made me consider building a simple conical extension for them. But you start running out of room again quickly.
The other idea I had was to use a pair of 8pe21 per horn (I collected 4) and mount them on a conical extension similarly to how Inlow did in his big petal conical midbass.
https://inlowsound.weebly.com/100-hz-12-sided-conical-horn.html
More than likely that would require a phase plug, as he used, which I would have to try and figure out or just “wing it”.
I tried a few other conical profiles from scratch in hornresp that mimicked Inlow’s other horns.
My overall impression was that either way I was not going to get much lower with the 8pe21 and that I would have to have a bass solution capable of coming up to meet it.
I’ve collected some 350Hz Edgar salad bowls and a few drivers to try in them for the top end along with rebuilt EVM15b that I figured I might mimic Volvotreter’s take on Bruce’s midbass horn.
In the end I decided I would have to wait until I developed more knowledge, skill and possibly had more room.
I’ve only used pre-fabricated horn solutions for any length of time.
I started with a used pair of Oris 200 horns and a variety of “fullrange” drivers. They are supposed to be basically a short Tractrix profile horn/waveguide.
There were a few reasons I moved on from them. They got knocked over and damaged…but I had already come to odds with the “head in a vise” directivity.
I wanted to move on to try multi-way horns and realized quickly that the “mid-bass” solution seemed like the most difficult problem to solve due to some of the basic issues being wrestled with here. Finding the space is not easy…and I currently have much less than the OP.
I just barely learned enough Hornresp to model a few ideas.
One of them was to try the 8pe21 on the Oris 200…thinking “hey, I have it” and I’d repair it. I just took mouth, length and throat measurements (approx. 21x12x7”) and worked backwards assuming a Tractrix profile.
It actually didn’t look that bad from about 200-800Hz…once you got the back chamber small enough. Although I asked myself how much of that is due to the Oris?
I got more out of the model by extending the length of the horn with an adapter and shrinking the throat to add compression. Which made me consider building a simple conical extension for them. But you start running out of room again quickly.
The other idea I had was to use a pair of 8pe21 per horn (I collected 4) and mount them on a conical extension similarly to how Inlow did in his big petal conical midbass.
https://inlowsound.weebly.com/100-hz-12-sided-conical-horn.html
More than likely that would require a phase plug, as he used, which I would have to try and figure out or just “wing it”.
I tried a few other conical profiles from scratch in hornresp that mimicked Inlow’s other horns.
My overall impression was that either way I was not going to get much lower with the 8pe21 and that I would have to have a bass solution capable of coming up to meet it.
I’ve collected some 350Hz Edgar salad bowls and a few drivers to try in them for the top end along with rebuilt EVM15b that I figured I might mimic Volvotreter’s take on Bruce’s midbass horn.
In the end I decided I would have to wait until I developed more knowledge, skill and possibly had more room.
Hello GM.
Trying to understand the comment above. I wasn't familiar with the Altec 825 so looked it up and if I'm understanding correctly it has a 515 15" driver on a 14" deep waveguide and a ported back chamber that exits on the front. Or maybe the back works as a back-loaded horn? What frequencies play through the lower port and what's the range on the front waveguide?
Didn't understand what you meant with the joints being in octave spreads. Joints in the back horn?
Thank you in advance!
on bowed bass viola - I like the sound of the little Acoustic Control 115BK Karlson box.- but Karlson aren't sensitive enough for flea- 3 watt power SE tube.
My "midbass"horn experience is limited - guess Sentry IV, FH1, Edgarhorn 100 would count- got 2-small 50Hz C-fold. - jo "J" horn Sentry IV, FH1, and Baby Belle bifurcated. Baby University Cl;assic very good - if had been made ione inch deeper then would have used a 12" instead. of 10"😢
A fiend many years back made a VOT type speaker using EV15L for bass guitar - - he made a 5 petal short horn/wg - back wave rest reflex with slot-shelf port below the horn. - it was very clear sounding and probaly had the traditional stepped response of thta type hybrid.
..
My "midbass"horn experience is limited - guess Sentry IV, FH1, Edgarhorn 100 would count- got 2-small 50Hz C-fold. - jo "J" horn Sentry IV, FH1, and Baby Belle bifurcated. Baby University Cl;assic very good - if had been made ione inch deeper then would have used a 12" instead. of 10"😢
A fiend many years back made a VOT type speaker using EV15L for bass guitar - - he made a 5 petal short horn/wg - back wave rest reflex with slot-shelf port below the horn. - it was very clear sounding and probaly had the traditional stepped response of thta type hybrid.
..
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Greets!
Hmm, I see I left out some info!
The majority of A7s used the 800, 416 series 15" with the 515 only being used as an option in prosound apps.
Correct, yes, it's a crude two segment BLH when the baffle boards are removed, making it a compound horn (actually basically a W.E. design that used movable louvers to tune it). It's normally tuned to 55 Hz, the front horn's flare frequency. It's ~110 - 342 Hz/F6.
Hmm, I see I left out some info!
Instead of using curves for flares, just used straight panels 'bent' (backside kerfed) to approximate a flare, a common way for decades now. The bend point(s) for expo are found by using (part of) octave spreads along its axial length or as I original did, drew the curved flares to scale and just picked what seem to look 'close enough' with the least bends.
The majority of A7s used the 800, 416 series 15" with the 515 only being used as an option in prosound apps.
Correct, yes, it's a crude two segment BLH when the baffle boards are removed, making it a compound horn (actually basically a W.E. design that used movable louvers to tune it). It's normally tuned to 55 Hz, the front horn's flare frequency. It's ~110 - 342 Hz/F6.
Octaves math:
Fh = Fl*2^n
Fl = Fh/2^n
n = ln(Fh/Fl)/ln(2)
where:
Fh = upper frequency
Fl = lower frequency, or the XO point in this case
n = octave spread
ln(2) = 0.6931
Historically -35 dB @ Fs for high power apps (no clue WRT today's mega power apps) with HIFI/HT 'high power' apps usually 'just' -24 dB: Fs*2^(order) = 2x Fs/4th, 4x/2nd, 7.1x/3rd, 16x/1st. Fs*2^(order) except 3rd = 2^(2*4)^0.5 = 2.828
Fh = Fl*2^n
Fl = Fh/2^n
n = ln(Fh/Fl)/ln(2)
where:
Fh = upper frequency
Fl = lower frequency, or the XO point in this case
n = octave spread
ln(2) = 0.6931
Historically -35 dB @ Fs for high power apps (no clue WRT today's mega power apps) with HIFI/HT 'high power' apps usually 'just' -24 dB: Fs*2^(order) = 2x Fs/4th, 4x/2nd, 7.1x/3rd, 16x/1st. Fs*2^(order) except 3rd = 2^(2*4)^0.5 = 2.828