Hi all.
First off, searched and read through previos threads. Actually Dave over at Planet 10 might already have an answer to this.
I've been wanting to build a FR setup for a while now. I already have a pair of Alpair 12P, and so I was wondering what anyone else here has done with this driver. I already know about the pencil's and super pencils. What about large MLTL designs, utilizing the 12P and something else (12PW, or helper woofer, or?) And, what about horns, I haven't found any designs for front (or back) loaded horns with the 12P and I would really like to try my hand at building those. They will have to be almost right against a wall so they would have to be front firing horns.
I have little in the way of speaker design knowledge, but a good understanding with wood and the tools to back it up. So don't be shy if you know about some larger designs.
Also, if anyone knows of someone who could do a few calculations I'd love to hear about it. I know a program isn't going to tell me all I need to know, but to be able to say for example "12P and helper woofer" need a chamber of this size, throat this size, length and mouth that size. It would be a very good place to start. I'd be happy to trade some of what I can do, for some of what I can not do, like make horn calculations.
Thanks guys.
First off, searched and read through previos threads. Actually Dave over at Planet 10 might already have an answer to this.
I've been wanting to build a FR setup for a while now. I already have a pair of Alpair 12P, and so I was wondering what anyone else here has done with this driver. I already know about the pencil's and super pencils. What about large MLTL designs, utilizing the 12P and something else (12PW, or helper woofer, or?) And, what about horns, I haven't found any designs for front (or back) loaded horns with the 12P and I would really like to try my hand at building those. They will have to be almost right against a wall so they would have to be front firing horns.
I have little in the way of speaker design knowledge, but a good understanding with wood and the tools to back it up. So don't be shy if you know about some larger designs.
Also, if anyone knows of someone who could do a few calculations I'd love to hear about it. I know a program isn't going to tell me all I need to know, but to be able to say for example "12P and helper woofer" need a chamber of this size, throat this size, length and mouth that size. It would be a very good place to start. I'd be happy to trade some of what I can do, for some of what I can not do, like make horn calculations.
Thanks guys.
Have you seen this: Woden Design | Avebury
Somewhere I've seen an open baffle setup with the 12p and woofers, but that's not what you want.
jeff
Somewhere I've seen an open baffle setup with the 12p and woofers, but that's not what you want.
jeff
I have indeed saw that Jeff, thank you. My concern with the Avebury is that is is still single driver. I would think it's getting to the limits of getting all one can out of a 12P (gen 2 by the way), and that is on the right track. But, although I've not built any large full range setups, I have listened to. I am going after a little more "oomph" than just one G212p can deliver.
This is where not having the software (or knowledge to use it) comes in. For example, in the same footprint of the Avebury I'm sure something could be come up with to run the 12P and another driver. I could run the 12P and a 12PW in just a single front exiting folded horn. Or, maybe the same in an MLTL, though I really would like to build a horn as I love woodworking and enjoy their appearance as well as sound.
And yeah you're right on the open baffle, not so much a fan of them. Although if it comes down to a dedicated woofer, instead of another semi full range like the 12PW, that's ok.
Honestly I've always liked the sound (and looks) of folded, front firing horns, like the frugal horns. Or double horns like the Pluvia build that TheJessMan has going on here now. I've had great luck making some smaller, single driver versions that sounded fantastic. But for this (even though they will most likely be in a 2.1 setup, and crossed over) I would really like to do it right and get a taste of my own true full range.
Thanks again
This is where not having the software (or knowledge to use it) comes in. For example, in the same footprint of the Avebury I'm sure something could be come up with to run the 12P and another driver. I could run the 12P and a 12PW in just a single front exiting folded horn. Or, maybe the same in an MLTL, though I really would like to build a horn as I love woodworking and enjoy their appearance as well as sound.
And yeah you're right on the open baffle, not so much a fan of them. Although if it comes down to a dedicated woofer, instead of another semi full range like the 12PW, that's ok.
Honestly I've always liked the sound (and looks) of folded, front firing horns, like the frugal horns. Or double horns like the Pluvia build that TheJessMan has going on here now. I've had great luck making some smaller, single driver versions that sounded fantastic. But for this (even though they will most likely be in a 2.1 setup, and crossed over) I would really like to do it right and get a taste of my own true full range.
Thanks again
A few general thoughts, FWIW:
A front loaded horn is a horn afixed to the front of the driver, it is not defined by the position of the terminus. Almost right back against a wall may (depending on definition & specific design) be beneficial with a rear terminus, since such a design will likely use the boundaries as a physical extension of the horn.
Fair enough, although that might depend on what your limits are & how you define them. (?)
Up to a point. But Avebury is big because it 'needs' to be. I design large horns (generally) because they are less compromised than small ones. There are / can be exceptions to this, often as a result of different design objectives (FH3 for example) but if you want to go low with a reasonably balanced output, bulk is a product and requirement of the laws of physics.
You could, but it would have to be large, if high performance is a criteria. I can do you a custom design if desired (I actually have a couple on the drawing board), but I understand you wish to do this yourself. One further point: a back loaded horn variation (i.e. where the rear of the driver loads the enclosure) is only useful over a relatively narrow BW. One of the objectives of this type of enclosure is to use the broadband gain to obviate the requirement for compensation of step-loss (remembering that you still can't run the cabinet especially high up: 250Hz - 300Hz is about the limit before GD becomes problematic). By running a 12PW alongside a 12P, you could use that as an alternative compensation. Add them both however, you may end up with excessive LF gain, especially since you say the enclosures will be up against a room boundary which itself goes a fair way to reducing baffle-step losses. Speaker design 'should' really be 'system design'. The ideal is to take a holistic view (reclaiming the term from the alternative therapists) of the system as a whole, including room acoustics, speaker position, listening distance, amplifier output impedance & any series R present etc., rather than viewing the speaker in isolation.
A front loaded horn is a horn afixed to the front of the driver, it is not defined by the position of the terminus. Almost right back against a wall may (depending on definition & specific design) be beneficial with a rear terminus, since such a design will likely use the boundaries as a physical extension of the horn.
Fair enough, although that might depend on what your limits are & how you define them. (?)
Up to a point. But Avebury is big because it 'needs' to be. I design large horns (generally) because they are less compromised than small ones. There are / can be exceptions to this, often as a result of different design objectives (FH3 for example) but if you want to go low with a reasonably balanced output, bulk is a product and requirement of the laws of physics.
You could, but it would have to be large, if high performance is a criteria. I can do you a custom design if desired (I actually have a couple on the drawing board), but I understand you wish to do this yourself. One further point: a back loaded horn variation (i.e. where the rear of the driver loads the enclosure) is only useful over a relatively narrow BW. One of the objectives of this type of enclosure is to use the broadband gain to obviate the requirement for compensation of step-loss (remembering that you still can't run the cabinet especially high up: 250Hz - 300Hz is about the limit before GD becomes problematic). By running a 12PW alongside a 12P, you could use that as an alternative compensation. Add them both however, you may end up with excessive LF gain, especially since you say the enclosures will be up against a room boundary which itself goes a fair way to reducing baffle-step losses. Speaker design 'should' really be 'system design'. The ideal is to take a holistic view (reclaiming the term from the alternative therapists) of the system as a whole, including room acoustics, speaker position, listening distance, amplifier output impedance & any series R present etc., rather than viewing the speaker in isolation.
Thanks very much Scott. I emailed you from your site as well, so we can do that, but I would also like to keep this going here.
Yes, and thanks for pointing it out. I know what you mean about the front and rear loaded horns, but I was under the belief that rear exiting horns had to be at least a few feet away from a wall. Also, I have seen some designs where the drivers were front and back loaded, in this case the front loading being a very shallow and quickly opening parabolic type.
What I meant was that I will be driving these with 50-100w available. Sure, most of the time the 1w rule applies. But when I get the itch to turn it up, I would like to be able to. A lot of the music I listen to has strong bass guitar content (rock, fusion, progressive, electronic jazz). I would like to be able to have them play full range, and so if they do see 40hz notes at say 40W I would like them to be capable.
And this is what I like about speakers like the Avebury, less compromises (I understand there are always some, that's physics). What I was trying to imply was not that I thought I could fit two drivers into what the Avebury needs for one. I apologize, I far over simplified... Well easier to say it like this, and also answer your last statement:
With an enclosure as large as the Avebury.... Actually, the height is a max for me. But the floor space (depth and width), I could double that. Where the statement originally came from was me thinking of all of the designs I had seen with MLTL's, and back loaded folded horns. Most of them are about half the height (at the most, a lot are less than half) and similar floor dimensions. As I had mentioned in the email, I thought about having the 12p in an MLTL sitting atop a folded horn for the PW. My ears prefer a little more gain from 500hz down, and so I thought it was something worth investigating. I understand (and respect) what you are saying about holistic system design. But I can only do that to a point. I will surely be running these with different amps as I build them through the years (though all tube so probably all close to .5-1 ohm). They will certainly always be near walls, in corners of the room. There will always be little added series R. So yes these things can be said but obviously there exist some slight variables.
So many of the simple designs like the pencil series get great listening reviews, from a good array of listeners. I'm just looking for something with a more solid low end that can handle more power as I described earlier. I do want to build it myself, but I am not opposed to working something out with someone for design assistance. If you have a couple of things on the drawing board, I would love to hear about them (at least types, driver content, etc). You are welcome to PM me.
And I'm not discounting other designs either. I would still like to hear about what some other people have done with the 12P as far as FAST designs with a helper woofer. Or Dave over at planet 10 was talking in other threads about Bernie doing something with the P and PW in a MarKen. And he said he had done some stuff with 2 of the 12P in an MTMTL.
Thanks again
Yes, and thanks for pointing it out. I know what you mean about the front and rear loaded horns, but I was under the belief that rear exiting horns had to be at least a few feet away from a wall. Also, I have seen some designs where the drivers were front and back loaded, in this case the front loading being a very shallow and quickly opening parabolic type.
What I meant was that I will be driving these with 50-100w available. Sure, most of the time the 1w rule applies. But when I get the itch to turn it up, I would like to be able to. A lot of the music I listen to has strong bass guitar content (rock, fusion, progressive, electronic jazz). I would like to be able to have them play full range, and so if they do see 40hz notes at say 40W I would like them to be capable.
And this is what I like about speakers like the Avebury, less compromises (I understand there are always some, that's physics). What I was trying to imply was not that I thought I could fit two drivers into what the Avebury needs for one. I apologize, I far over simplified... Well easier to say it like this, and also answer your last statement:
With an enclosure as large as the Avebury.... Actually, the height is a max for me. But the floor space (depth and width), I could double that. Where the statement originally came from was me thinking of all of the designs I had seen with MLTL's, and back loaded folded horns. Most of them are about half the height (at the most, a lot are less than half) and similar floor dimensions. As I had mentioned in the email, I thought about having the 12p in an MLTL sitting atop a folded horn for the PW. My ears prefer a little more gain from 500hz down, and so I thought it was something worth investigating. I understand (and respect) what you are saying about holistic system design. But I can only do that to a point. I will surely be running these with different amps as I build them through the years (though all tube so probably all close to .5-1 ohm). They will certainly always be near walls, in corners of the room. There will always be little added series R. So yes these things can be said but obviously there exist some slight variables.
So many of the simple designs like the pencil series get great listening reviews, from a good array of listeners. I'm just looking for something with a more solid low end that can handle more power as I described earlier. I do want to build it myself, but I am not opposed to working something out with someone for design assistance. If you have a couple of things on the drawing board, I would love to hear about them (at least types, driver content, etc). You are welcome to PM me.
And I'm not discounting other designs either. I would still like to hear about what some other people have done with the 12P as far as FAST designs with a helper woofer. Or Dave over at planet 10 was talking in other threads about Bernie doing something with the P and PW in a MarKen. And he said he had done some stuff with 2 of the 12P in an MTMTL.
Thanks again
A12pWeN MTM with A7.3eN.
We are also doing a modular MTM design with A12pw in an optimum miniOnken (about 2x as big as optimum for A12p). Take a miniOnken, add a small box specifically designed for midTweeter duty, and then flip another A12pw miniOnken on top.
Here is an early sketch with A7, but A12p is certainly possible. I would not normally look at the A12p as a midTweeter since, except for dynamics capability*, all the other current Mark Audio drivers do a better job. Many of them also go lower. But the A12p with a pair of A12pw would kick ***.
*(it is quite stunning what a helper woofer(s) bring to the table in terms of dynamics)
With A12p as midTweeter my 1st thots go to a larger driver as a bass helper. 10, 12, even 15”. Or a pair of them... I have a pair of boxes with push-push SDX10 that would be a good match, and i have a LOT of 12” vintage Foster bass drivers downstairs on the shelf…
dave
We are also doing a modular MTM design with A12pw in an optimum miniOnken (about 2x as big as optimum for A12p). Take a miniOnken, add a small box specifically designed for midTweeter duty, and then flip another A12pw miniOnken on top.
Here is an early sketch with A7, but A12p is certainly possible. I would not normally look at the A12p as a midTweeter since, except for dynamics capability*, all the other current Mark Audio drivers do a better job. Many of them also go lower. But the A12p with a pair of A12pw would kick ***.
*(it is quite stunning what a helper woofer(s) bring to the table in terms of dynamics)
With A12p as midTweeter my 1st thots go to a larger driver as a bass helper. 10, 12, even 15”. Or a pair of them... I have a pair of boxes with push-push SDX10 that would be a good match, and i have a LOT of 12” vintage Foster bass drivers downstairs on the shelf…
dave
Twice the depth means you have lots of room to play with how far a rear horn is from the wall behind it (6-18”).
I’d guess that an Avebury-like horn for A12pw would be near twice the volume and in any but the largest rooms you would have to “EQ” out some bass level. The balance in the ML-TL & the miniOnken are about right.
dave
Thanks Dave! That's great, that's the stuff I was seeing alluded to in the other posts, the dual mini-onken. As far as the helper woofer, you'll have to let me know what exactly you have as far as those 12" Fosters, I'd like to check out some data sheets.
Yes I had heard the same thing from a lot of people about the 12P not going as low or as high as some of the other MA drivers, but you're right that doesn't mean it doesn't have its own merit. I enjoy the sound of larger (5"+) paper cone full ranges in all but the largest enclosures. Sure I could do something like the Avebury and get a sound I like, but then back to the volume level...
Going back to the helper woofers, like I said you'll have to let me know model. Another thing that is important to me on this build is a lack of crossover components. Any helpers I consider will have to have a smooth roll off. Another set of woofers ( that I have) are those from a pair of old KLH model 17's. They're good for direct hookup, nice smooth roll off, but they also roll off at about 100hz quite steeply in the stock KLH boxes. The tone is amazing, and lots of people agree on that, but I have yet to find exact specs on them or anyone who has tried them in any other enclosures. I'm sure they'd do better in a BR or MLTL but how much so it's hard to tell without any info.
The MTM with the 12pw and the 12p would be excellent, but it would put me having to source 4 12pw. Not that that's a problem, but seems like you're right I'd be doing even better with a helper woofer and the 12p in 2 enclosures built into one. If ever I had the desire to add something on the very top end, some AMT or similar I could easily incorporate that after the fact.
Thanks again
Yes I had heard the same thing from a lot of people about the 12P not going as low or as high as some of the other MA drivers, but you're right that doesn't mean it doesn't have its own merit. I enjoy the sound of larger (5"+) paper cone full ranges in all but the largest enclosures. Sure I could do something like the Avebury and get a sound I like, but then back to the volume level...
Going back to the helper woofers, like I said you'll have to let me know model. Another thing that is important to me on this build is a lack of crossover components. Any helpers I consider will have to have a smooth roll off. Another set of woofers ( that I have) are those from a pair of old KLH model 17's. They're good for direct hookup, nice smooth roll off, but they also roll off at about 100hz quite steeply in the stock KLH boxes. The tone is amazing, and lots of people agree on that, but I have yet to find exact specs on them or anyone who has tried them in any other enclosures. I'm sure they'd do better in a BR or MLTL but how much so it's hard to tell without any info.
The MTM with the 12pw and the 12p would be excellent, but it would put me having to source 4 12pw. Not that that's a problem, but seems like you're right I'd be doing even better with a helper woofer and the 12p in 2 enclosures built into one. If ever I had the desire to add something on the very top end, some AMT or similar I could easily incorporate that after the fact.
Thanks again
I took a look Dave, and now I remember I had looked at the SDX10 previously. Wouldn't 2 in push push be a little overkill, for just one 12P to pair with?
As for the Foster, couldn't find much info so yeah, let me know.
As for the Foster, couldn't find much info so yeah, let me know.
Maybe, maybe not.
You won’t. Vintage salvage from a common Sears brand speaker. ~1.5 ft^3 per woofer is nice for sealed.
dave
Yeah that was the info that I did find...was that they came from a Sears "professional" speaker setup. I found pics of one pair, looked to be a butyl surround not just paper like a lot of the older woofs. Interesting. As for the SDX, were they something you were seriously considering selling, or just a mention? After doing a bit more research on them I would certainly hop on a pair if I got the chance (or maybe a quad as the case may be, depending on your position). If they were too much for one, they would certainly not be too much for two. And if I went that route (2 12p) It would be a bit easier to figure dimensions using existing boxes designed for just the 12p as a starting point.
I'm also waiting to hear back from Scott. All just ideas still, but nice to know available options. Thanks again Dave,
I'm also waiting to hear back from Scott. All just ideas still, but nice to know available options. Thanks again Dave,
I've heard Dave's system with the dual push-push SDX10s, and in his very open space that is much larger than I have to work with, they don't really sound like overkill. Powered by a cute little Sure 4-channel ("100w") amp
Thanks Chris. I ended up ordering a pair of SDX10's as well as a pair of SDX12. The more research I did the more appealing they both were. I have almost always run a 2.1 system actively crossed at 80-100hz but the 12 looks like it would really give me the capability to run true stereo and nothing else. Having solid, clean performance down to 30hz (not F6 30hz like so many speakers) is important to me. The 10's are also very nice so when they get here first things first will be building their ends of the enclosure and seeing how they are in my space. I really wanted to run this system without crossovers but we'll see. It is appealing as well to run the 12p from say 600hz up, thus minimizing it's documented issue with the 500hz 2nd order distortion.
And so again, still interested to hear about what anyone else has done with the 12p...
Thanks guys
And so again, still interested to hear about what anyone else has done with the 12p...
Thanks guys
If you are talking F3 it is a menaingless spec to the ear/brain (ref Toole), one needs to look at F6 and F10. If you have a woofer flat to 30 Hz, in most cases you will have too much bass because you have not accounted for room gain.
I would say it is a waste to cross the A12p as high as 600 Hz. You want as much of the vocals in a single driver as possible, so 200-300 Hz (depending on the box design) is more appropriate i’d think. The only scientific study ever done on ear/brain perception of the distortion we measure suggests that these distortion measurements are meaningless (ref Geddes). I have not had an issue with A12p in this respect (or A12pw/A10p/A6.2p)
And from the published response curve anything over 200 Hz is going to be iffy for the SDX12.
dave
Thanks Dave. I should have mentioned, I was still planning on another full range like the 12pw to take care of that 200-600 gap and reinforce the top end. I understand what you mean about the distortion measurements but another builder (who I will not mention) had said that the 500hz distortion was an issue, at least that was how I understood him. In any case, yes I want at least a, if not both, full ranges covering the vocal range, well 200-4K. And hopefully that will do it, I'll see how my ears like them also covering all the way up into the top end of my hearing. I am glad to hear you have not had any issues with the 12p though, thank you again.
Even with an A12pw in-between, the C-C distance between will suggest an XO between them below ~400 Hz. Try things out 1st without the filler driver.
dave
dave
Dave...I had considered trying just the a12p first but its definitely something to give some thought. If I was to do that I think I would go with the SDX 10 and not 12. The reason being that as far as design goes and building all of this, I can't think of any enclosure where I could just add the 12pw if I decided I needed it, except for a dipole setup of some sort where at first I would just have the 12p in the front, and then possibly the 12pw to be added if I thought it necessary. I mean, I could build one of the larger boxes with 2 drivers, like a few of the ones you have, and we've talked about, but it would not be optimal for just one 12p and would give me a biased view. Am I missing something you were thinking, or were you just saying you think a single 12p in one of the simple cabinets would be enough?
I am also going to look into Tooles book. I am quickly getting to the point on this where I have more questions and have spent long enough not knowing much about actual design in speakers. I would like for this to eventually be an educated effort on my part. Your suggestions are very helpful, but I'm sure you agree I should read it.
As for the crossovers yes again if I can get away w/o on the fr driver(s?) that would be optimal. As for the SDX 12, looking at the published graph I agree with you, but that is a graph of near field response open baffle...the sdx10 looks great of course, but those are sealed and ported measurements. Do you know anywhere that there are more measurements with the 12 in enclosures?
Thanks again,
I am also going to look into Tooles book. I am quickly getting to the point on this where I have more questions and have spent long enough not knowing much about actual design in speakers. I would like for this to eventually be an educated effort on my part. Your suggestions are very helpful, but I'm sure you agree I should read it.
As for the crossovers yes again if I can get away w/o on the fr driver(s?) that would be optimal. As for the SDX 12, looking at the published graph I agree with you, but that is a graph of near field response open baffle...the sdx10 looks great of course, but those are sealed and ported measurements. Do you know anywhere that there are more measurements with the 12 in enclosures?
Thanks again,
So I just listened to 2 lectures given by Toole. Interesting that Bass frequencies from 120hz down account for 30% of our "listening experience", that being the experience of the music dealing with all audible frequencies. Also, the way that low frequencies change in perceived volume much more quickly than higher frequencies, as compared to actual power change.
The example he gave was that at 2khz a change of 10db would be considered "twice as loud" whereas at 50hz a change of 5db would be considered "twice as loud"
A lot of other things as well. But a good starting point is that I am going to have to see how that SDX12 behaves in room and in a box. I would still like to find some measurements of it in box(es)....
I'll keep searching, reading, and listening. Thanks again
The example he gave was that at 2khz a change of 10db would be considered "twice as loud" whereas at 50hz a change of 5db would be considered "twice as loud"
A lot of other things as well. But a good starting point is that I am going to have to see how that SDX12 behaves in room and in a box. I would still like to find some measurements of it in box(es)....
I'll keep searching, reading, and listening. Thanks again
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