Hi,
I'm looking for a horn loaded solution, 50 to 350-400 Hz to suit 15" driver.
Having looked around it seems to 'hear' these things is difficult to realize - although I did enjoy La Scala, despite the LF shortcomings.
A straight horn is not going to cut it, needs proper output down to ~50 Hz so that a sub is not mandatory, folded horn is an acceptable compromise.
Based on many hours of 'reading' I have shortlisted the following:
Room is 170 M3 with 2.7M ceiling. Concrete floor. Walls and ceiling are timber stud frame with fiberglass (batting) insulation and 10mm drywall.
M/HF is 2" CD on Fc 200 Hz JMLC horn (at hand), crossed ~350 Hz, 750 mm diameter. The 200 Hz horn center doesn't need to be at 'seated ear height', all above cabinet heights are close to okay.
Looking for real-world advice to assist with narrowing down options, subjective or objective, but asking for real world experience, thanks.
Cheers
I'm looking for a horn loaded solution, 50 to 350-400 Hz to suit 15" driver.
Having looked around it seems to 'hear' these things is difficult to realize - although I did enjoy La Scala, despite the LF shortcomings.
A straight horn is not going to cut it, needs proper output down to ~50 Hz so that a sub is not mandatory, folded horn is an acceptable compromise.
Based on many hours of 'reading' I have shortlisted the following:
- University Classic or Dean
- EG Beck California
- 2x Quarter Pie - 2 cabs side by side, straight edged version with larger deflector and stacked side by side 'on end'
- La Scala or Peavey FH-1 with 'bass reflex add-on'
- Karlson 15
- Onken W (?)
Room is 170 M3 with 2.7M ceiling. Concrete floor. Walls and ceiling are timber stud frame with fiberglass (batting) insulation and 10mm drywall.
M/HF is 2" CD on Fc 200 Hz JMLC horn (at hand), crossed ~350 Hz, 750 mm diameter. The 200 Hz horn center doesn't need to be at 'seated ear height', all above cabinet heights are close to okay.
Looking for real-world advice to assist with narrowing down options, subjective or objective, but asking for real world experience, thanks.
Cheers
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I don't think you'll find a suitable woofer - other than an original University - for the Classic, or Dean. Find the Bruce Edgar article on 'The Show Horn' where he does mention the Classic and explains how to determine the mass rolloff traits for an 'enclosed' woofer with a restricted throat.
I think the QTS of the 15pr400 might be a bit high for horn loading......but i'm no expert in this regard either.
The Klipsch MWM folded horn response is +/-5dB from 42 to 500Hz.
From my experience, and any available measurements and simulations I think it would outperform all the cabinets on your "short list".
It used K-43 drivers, which have similar TS parameters to your Faital Pro 15PR400.
The cabinet is fairly easy to build.
I took measurements when I rebuilt a pair that were involved in a truck accident in the mid 1980s.
3/4" plywood was used throughout. The 44.5" depth allowed two to fit in a standard 90" truck box.
The exterior height was 32.25", 30.75" interior.
The Faital Pro 15PR400 are 15.47"diameter, so would require a bit more height, or a slight recess cut in the top and bottom of the compression chamber. It's baffle cutout diameter is 14.02", increase it from the 13" noted.
If I recall correctly, the original speaker used double fiber gaskets, so 1/4"-1/2" "donut" standoff gasket will probably be needed to allow full excursion of the 15PR400, or a 1/4" depth round circle routed in the baffle.
The triangular baffle cutouts in the speaker baffle increase the compression chamber volume, connecting it to the triangular chambers either side of the initial horn flare.
The center braces are not shown, but basically divide the cabinet in half. Half versions (the MWM 1900) were also available.
I still remember the impressive low bass these cabinets produced, which surprised me considering the (K-33) CTS stamped frame, square magnet drivers Klipsch used in them prior to the K43.
CTS became Eminence, their 15162 PART # K-33:
RE OHMS 3.39
FS HZ 34.46
LE MH .96
MMS GMS 78.59
QM 7.39
CMS mm/N .2714
QE .410 RMS NS/M 2.3037
QT .390 VAS LTRS 301.66
XMAX MM 8.20 SD SCM 889.59
BL TM 11.88
EBP 84.4
Cheers,
Art
The cone on the 15PR400 isn't very well suited for horn loading IMO. Thats speaking from a stiffness perspective and how well the cone resists radial breakup deformation. I'd choose a ribbed cone driver like those on the Delta or Kappa series Eminence 15s.
Thanks Art,
Thats a beast, I converted measurements into cm and a pair will fit in the room quite okay.. but there is really no way of getting around the size of them.
Part of me likes it for that, the other part says 'you can never get married again' - and part of me likes that too 🙂
As an intermediate thought, I could cut it in half (more or less) and build it as the 'quarter pie' (double) - which was apparently based on 'half' a Klipsch WMW; stand them upright, fit the JMLC horn on top, or at the side.
Any thoughts on this?.
Profiguy - thanks also, unfortunately these are the drivers that I have, so I will use them. People have used them in horns before, Volti for example LaScala clone. My hope is that it'll work and be 'good enough'. I could look into selling them NIB, but it would be another detour, and if 'good enough' is 'good enough', then .. I'm okay with that.
What I do know, is that I want horn loaded bass.
Cheers
Thats a beast, I converted measurements into cm and a pair will fit in the room quite okay.. but there is really no way of getting around the size of them.
Part of me likes it for that, the other part says 'you can never get married again' - and part of me likes that too 🙂
As an intermediate thought, I could cut it in half (more or less) and build it as the 'quarter pie' (double) - which was apparently based on 'half' a Klipsch WMW; stand them upright, fit the JMLC horn on top, or at the side.
Any thoughts on this?.
Profiguy - thanks also, unfortunately these are the drivers that I have, so I will use them. People have used them in horns before, Volti for example LaScala clone. My hope is that it'll work and be 'good enough'. I could look into selling them NIB, but it would be another detour, and if 'good enough' is 'good enough', then .. I'm okay with that.
What I do know, is that I want horn loaded bass.
Cheers
W Bins are great! We used to build single driver bins with the JBL2226 and stack them or stand em up side by side depending on the venue size and coverage needed from the Mid/horn top. Still IMO the best midbass solution.
.. mayhem13
Carry on and disregard potential 15PR400 cone rigidity issues (or non-issues)?/.
Cheers
Carry on and disregard potential 15PR400 cone rigidity issues (or non-issues)?/.
Cheers
I really can’t offer an opinion as I have little to no experience designing horns…..the W bins I mentioned were a common pro design that was shared in publications back in the day before the internet when we used slide rules to calculate! Lol
I can only offer that what I’ve read and seen in hifi horns is consistent with low QTS and rigid ribbed cones to handle the pressure.
Now here’s the thing….for home use and amplifier power being very cheap these days….the 15pr400…already an excellent woofer and very efficient………I don’t/can‘t see a need to horn load them at all. I think a well designed and braced reflex is all that’s required here. W bins sound great…..but they’re big and more difficult to build.…..and the long panels tend to resonate a bit.…….a large braced reflex no so much. Since you already have the Faitals…..I say reflex instead.
I can only offer that what I’ve read and seen in hifi horns is consistent with low QTS and rigid ribbed cones to handle the pressure.
Now here’s the thing….for home use and amplifier power being very cheap these days….the 15pr400…already an excellent woofer and very efficient………I don’t/can‘t see a need to horn load them at all. I think a well designed and braced reflex is all that’s required here. W bins sound great…..but they’re big and more difficult to build.…..and the long panels tend to resonate a bit.…….a large braced reflex no so much. Since you already have the Faitals…..I say reflex instead.
The bifurcated horn path of the MWM would put the bottom half too far away from the HF horn to properly integrate.
Your drivers Mms is in between the K43 and the K33 cones that I heard, the K33 being lighter than yours.
Higher Mms drivers with similar Xmax generally have stiffer cones.
If pushed hard below Fc (horn cutoff) or Fb (Frequency of box tuning) light cones deform or tear, like the K33 example below:
Note the K33's extended gasket depth compared to your drivers.
At any rate, with your PWR-ICE12 you can HP the woofers so that won't happen, and EQ the response to fit your preferences.
Horn loaded bass like the MWM has sounds great (in a great room...), but the path length difference between a horn with the necessary length to go low and your high frequency horn, as well as the bass horn folds make for problems in the crossover region.
If I were considering a large 2-way horn system, my preference would be a straight horn with bass reflex porting, like Cal Perkin's 4550. The TS parameters of the JBL E145 drivers used in it are also similar to your drivers, though even less Mms than your drivers.
In my opinion, the compromise of bass reflex from Fb to ~100Hz where the bass horn kicks in is more than compensated by the smoother, time aligned response in the crossover region. The 4550 can sound quite good up past 600Hz, relaxing the excursion demands that are placed on the high frequency driver when crossed within an octave of Fc.
Anyway, getting the low midrange and crossover region to sound good is critical to any system, but it's a lot easier to do with straight horns than folded horns.
Art
Are you familiar with the PPSL concept? (Push-pull, slot load) Using twin 15PR400 per side will give you some tremendous output. Will also give you a cut-off much lower than 50Hz. The only caveat to this concept is the upper frequency limit. I'm not so sure about getting as high as 350Hz in a linear fashion. Having said that, some experienced builders get fine response as high as 400Hz. It's all about the details in the construction of the plenum. The PPSL is like a 1/2 step between a direct radiator bass system, and a full blown horn system. Of course, a proper horn reins supreme, indeed, but to get satisfactory bass, will be quite large. A 50Hz cut-off with a steep slope (like bass horns are) will be missing the low bass ambient cues that make music so enjoyable. Only my 2 cents worth.
Yes.
Those builders used smaller drivers, which use smaller plenum cavities, which can push the usable upper limit above 350Hz.
The above outdoor half space ground plane response was of a cabinet using the minimum plenum volume possible with two 15" drivers, I'd consider the response much above 300Hz unusable due to the first -24dB cavity null at 400Hz.
Other than the added air mass, narrow band resonance peaks and dips the plenum causes, and reduction of even order harmonic distortion, past the near field there is virtually no difference in the response of a PPSL and a standard bass reflex with the same Fb.
Art
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If the MWM was built as the 'full version' and stood on its side with the M/HF horn mounted to the side?. ~180cm 'high' is okay and the reduced footprint makes it an acceptable physical fit.
I had a similar thought with HP and EQ - also a relatively easy life in a domestic setting (compared with live sound in a typical venue).
I will have a look at the Cal Perkins 4550.
Thanks to all. Much appreciated.
That would be better than the horn on top, but lateral "imaging" will be weird, drifting left to right (inside/outside) above and below the crossover range.
The side wing volume could be moved to the bottom of the cabinet, and the box made trapezoidal to better fit in room corners if desirable:
The ports could be extended to reach deeper than the original tuning above 40Hz Fb.
Your drivers would work well with a 35Hz tuning.
These Nova Eletronica 4550 plans from 1984 omit the ports used in the 4550A:
Anyway, easier to customize the 4550 to fit your desires than the MWM.
Art
I am using Karlson K15 speakers for 60 to 350 hz. One large advantage of this design is bass down to 60 hz in a relatively small package (22x22x34 inches). I did have a peak at ~300 hz, which took some effort to get this under control.
The Karlson speaker is a very viable means for this frequency range.
I tried the Karlsons for reproducing higher frequencies (up to 1000 hz), but did not like the result.
Retsel
The Karlson speaker is a very viable means for this frequency range.
I tried the Karlsons for reproducing higher frequencies (up to 1000 hz), but did not like the result.
Retsel
The 4550A look good to me as-is. 91cm height is okay, overall proportions are good and preferable to MWM.
I understand what you say about the straight horn being easier to integrate (and integrate better), so for overall presentation this is probably where I want to be. The depth of the cabinet lines up with the length of the M/HF horn. I dont know much about the inner workings but from the cut-out it looks likes the drivers are 'less loaded' compared with MWM, and considering previous about 15PR400, I guess this can only be a good thing.
Simply block a few ports (as they do with the Onken) to get that 35Hz tuning?.
You did say extend - so I'll assume that - obvious next question is 'how to do that' with minimal departure from the existing plans.
I know it's only You Tube, but I get a good impression from what I hear - that effortless open bass is there, from what I read its properly horn loaded down to 100 Hz, BR below and with no sub required as per the brief.
JBL 375/075/4550 (youtube.com)
JBL 4550BK/2440/2360-Hartley 24”-Ampex 6446 (youtube.com)
Thanks Art,
Cheers!
Hi Restel,
Thanks and that's what had me interested in the Karlson 15. Some sort of loading, not sure what it is or how it works but adds something which I'd probably like - but its an unknown to me.
With the 4550KBA cabinets, I like the look, the legacy and from reading around it seems people really like them. I can hear in the those you tube clips what I liked about the La Scala bass (limited as it was) and also a copy of the azura 50Hz bass horn (J shaped) - that very same thing, it's where I want to be, and on balance it seems the lowest-risk. I'll paint them (matt) black 🙂
Cheers
The further your ears are vertically off axis of the 2x15", the more comb filtering (peaks and dips resulting from the difference in distance between the drivers and your ears) is audible. My preference would be the center between the top cone and the HF horn be at ear height.
A greater throat to mouth ratio increases efficiency, which is also a "good thing".
Your drivers would be OK with the MWM's 7" throat width driven to Xmax, but will have less loading stress (and SPL output..) in the 4550 design when pushed near Xmax.
Reducing cross sectional area of ports lowers the Fb, but increases turbulence.
As was typical of the time, the 4550A's four 5.375" x 6.75" ports (total cross sectional area of 145 square inches, equivalent to a single 12" x 12", one square foot port) are only the depth of the 3/4" plywood, still not much port volume- easy to "blow out" that type of port if you were to reduce the cross sectional area.
That said, the proximity of the ports to the side and horn walls increases their effective depth (or end correction factor "K") compared to if the ports were on a flat panel, like the sides of the cabinet, or a large front baffle.
Going "old school", using JBL's loudspeaker enclosure venting nomograph, with a Vb (net box volume) of 21 cubic feet (~the 4550's net interior volume) and a Helmholtz frequency (Fb) of 40-42 Hz (as seen in the minimum impedance of the charts in post #15) we are slightly "off the chart" both on the Vb and Lv (vent length), a .75" port length would use ~125 square inches.
Fb remains the same regardless of the driver used, indicating there are some problems in the charts in post #15.
Since we know around 145 square inches was used to achieve ~40-42Hz Fb we could extrapolate the length of each port would need to be around 5" long to drop the tuning to 35Hz.
You can verify Fb by measuring the impedance minima between the two lower peaks, or watching the cones excursion minima while sweeping a sine wave around Fb.
Art
I've had very good results with a "bass reflex" LaScala type bass bin, coupled to an enlarged upper horn chamber "ported" with a 15" passive radiator and a JBL 2225 woofer. with some mild DSP PEQ, I'm able to get it +/- 3db from 20Hz to 20kHz.
I need to update my thread, I've had some improvements since my last post here.
my last measurements as part of a more detailed thread:
https://audiokarma.org/forums/index.php?threads/la-scalus-lascala-chorus-hybrid.1037523/post-1720628
I need to update my thread, I've had some improvements since my last post here.
my last measurements as part of a more detailed thread:
https://audiokarma.org/forums/index.php?threads/la-scalus-lascala-chorus-hybrid.1037523/post-1720628
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