OK, I have completed the speakers, and listened both with and without a speaker on the top. I prefer the two-driver speakers, but I am not sure that the improvement is due to the second speaker firing up, or simply the presense of two drivers. With one driver, there was less ambience, and the impression that the sounds were emerging from single points on each speaker. This may have bothered me due to decades of listening to multi-driver speakers, and may be preferable to others. There is also more SPL and a sense of greater ease in playing at realistic volumes. Imaging is quite good either way, although probably better with the single driver configuration. And, yes, these drivers are truly amazing. I have put aside my longstanding favorite Genesis Tech IM-8300, a 3-way sealed speaker with a wonderful dome midrange and ribbon tweeter. The Alpairs don't go as high as the ribbons, but I am hearing things I have never heard before from very familiar music. (I am also getting to the age where the high frequency extension of the ribbons is inaudible anyway.)
The MJK model for the two driver speaker indicates an earlier rolloff in the bass due to the small volume of the cabinet, and more ripple due to the second driver on the end. I have stuffed the two driver speakers more heavily, and I also use a sub woofer with DSP room correction, so the low-end rolloff is easily corrected. I have no idea what "ripple" sounds like, but the extra stuffing should be making this inaudible.
Now, my next project is standing next to the finished speaker in the photo. It is a 48" pipe, 12 inches in diameter with 3/4" thick walls (used for servicing municipal water supplies and rated at 364 psi). I plan to mount 4 drivers in this pipe (I have 2 Alpair 10.2 and 2 CSS EL-166 drivers per speaker). I am soliciting advice as to where to mount these drivers. I will attach plywood tops and bottoms. My inclination is to mount the Alpairs in the front and the EL-166s in the back in a classic bipole arrangement. I am also considering one Alpair in the front, one on top and the two EL-166s in the back. Another intriguing option would be to put all four drivers at the same height, spaced 90 degrees around the column in an omnidirectional configuration. This prototype really allows putting drivers anywhere on the column.
Any thoughts or advice? The beauty of PVC is the ease of prototyping. Once I have my optimal speaker, I will have a WAF-cabinet built. I am hopeless at wood-working...
Jack
The MJK model for the two driver speaker indicates an earlier rolloff in the bass due to the small volume of the cabinet, and more ripple due to the second driver on the end. I have stuffed the two driver speakers more heavily, and I also use a sub woofer with DSP room correction, so the low-end rolloff is easily corrected. I have no idea what "ripple" sounds like, but the extra stuffing should be making this inaudible.
Now, my next project is standing next to the finished speaker in the photo. It is a 48" pipe, 12 inches in diameter with 3/4" thick walls (used for servicing municipal water supplies and rated at 364 psi). I plan to mount 4 drivers in this pipe (I have 2 Alpair 10.2 and 2 CSS EL-166 drivers per speaker). I am soliciting advice as to where to mount these drivers. I will attach plywood tops and bottoms. My inclination is to mount the Alpairs in the front and the EL-166s in the back in a classic bipole arrangement. I am also considering one Alpair in the front, one on top and the two EL-166s in the back. Another intriguing option would be to put all four drivers at the same height, spaced 90 degrees around the column in an omnidirectional configuration. This prototype really allows putting drivers anywhere on the column.
Any thoughts or advice? The beauty of PVC is the ease of prototyping. Once I have my optimal speaker, I will have a WAF-cabinet built. I am hopeless at wood-working...
Jack
Attachments
Dave,
Internal diameter is 11.75 in. I am building two speakers.
I have modeled this enclosure with 2 Alpairs in the front and 2 EL-166s in the back, using MLK's bipole MathCad sheet, and it looks good. It would be fairly easy to fit a vertical piece of plywood inside the pipe to form 2 separate TLs, if necessary. I have thought about doing this to load the Alpairs in such a way as to minimize excursion. However, looking at the model, I don't understand why the Alpairs and EL-166s can't share the same TL.
Any thought about where to place the drivers on the column?
Thanks, Jack
Internal diameter is 11.75 in. I am building two speakers.
I have modeled this enclosure with 2 Alpairs in the front and 2 EL-166s in the back, using MLK's bipole MathCad sheet, and it looks good. It would be fairly easy to fit a vertical piece of plywood inside the pipe to form 2 separate TLs, if necessary. I have thought about doing this to load the Alpairs in such a way as to minimize excursion. However, looking at the model, I don't understand why the Alpairs and EL-166s can't share the same TL.
Any thought about where to place the drivers on the column?
Thanks, Jack
Almost perfect for doing a variation on Scott's twin ML-TL. We know this works VERY well. Leaves no room for a subchamber for the A10s.
The MJK sheets will not show the EL166 modulating the A10 and muddying up their performance. The A10.2 need to be in their own enclosure, and it should be optimizedf or mid tweeter use (ie a sealedbox or an aperiodic one (my preference)). The A10 also benefit from a high pass and the EL166 from a low pass. Given the potential downward xtension of the A10 bi-ampingis called for.
I'd also look to using just one A10.2 as mid-tweeter myself -- i stuggled with the use of 1 or 2 midtweeters for the statement design i am working on and decided to use a single A7.3.
Woofers on the side push-push, A10 within 1/4 wavelength at the XO.
dave
Attachments
I think Dave said "push-push" - meaning 2 woofers per cabinet - whether one on each sides or font/back is up to you, but we generally do them on the sides if cabinet is wide enough for them to fit. .
edit: I'd be inclined to use a single A10 per side, and build as separate modules, with the woofer enclosure sized to serve as stands.
Dave - drawing of the woofT / MarKen?
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I think Chris was thinking of the one he is working on (for the wide trapezoids and using 2 x EL166 in the (as yet unpublished) short ML-TL(32")), the picture i found quickly is for the one for the uFonkenSET with 2x4" Peerless -- Bernie is working on a set of those to match the solid Yew set of uFonken he built for me (drivers finished shortly). These are the same 32" height as the bigger EL166 ones.
The illustration does shoe how the drivers are side mounted in push-push opposition.
dave
Pretty-Up / Hide ABS pipe speakers
One can dress up ABS to a certain extent. Baffles and bases can be made to look fairly attractive to speaker guys; but not to spouse's. Most people, in fact, see only the ABS pipe, not the finished baffles or bases. The pipe can be completely hidden behind the baffle, but I like the pipe look. The great benefit of ABS remains the vibration free enclosure. The worst aspect is not the appearance of the speaker but the limited cross sectional area available with affordable sizes of pipe. I have not had a chance to work with the Alpair 10 yet but think it will work well in a six inch or greater pipe.
Rob
One can dress up ABS to a certain extent. Baffles and bases can be made to look fairly attractive to speaker guys; but not to spouse's. Most people, in fact, see only the ABS pipe, not the finished baffles or bases. The pipe can be completely hidden behind the baffle, but I like the pipe look. The great benefit of ABS remains the vibration free enclosure. The worst aspect is not the appearance of the speaker but the limited cross sectional area available with affordable sizes of pipe. I have not had a chance to work with the Alpair 10 yet but think it will work well in a six inch or greater pipe.
Rob
Attachments
Note to those that don't recognize Rob (aka Audio-Lego). He has done lots of work with PVC speakers. Laying Pipe with Audio Lego
dave
An externally hosted image should be here but it was not working when we last tested it.
dave
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