Recently saw the review for the Neumann KH 150s over on ASR and it impressed me with just how technically strong a 2 way can be with DSP implementation at its core, and it got me thinking, can a DIYer get to that level without spending MSRP of $3500 USD? I've seen the measurements for the March Audio Sointuva as a passive speaker, really elite, and that got me inspired to see if a DSP version of that can, in theory, match the KH 150 as a benchmark.
I'm going to treat this like an executable project, even if I don't go all the way and finish, which means deciding on parts, prices, cabinets, amps, DSP software, bracing, since all of that comes with the sticker price of the KH 150. We'll save the really hard part for later on, (measurements for the XO, in-room adjustments, near-field).
Some considerations, I think the KH 150s are all around solid, but I wouldn't call them beautiful per se. Beautiful to me is the Purifi 2 way Joachim Gerhard released a few years ago, see here: link. I really, really love walnut, so I'm immediately leaning towards a walnut baffle even though this might cause pains in the future for resonance. Another pain point, I'm thinking maybe I don't want to rebuild a cabinet every few years if I want to swap out drivers, maybe I like the idea of removing the baffle and driver swapping. This would be huge down the line for flexibility, and it means that in theory, I can do a sealed box, a passive radiator box, or a ported box in the future if I simply also swap the back baffle. So front and back removable walnut baffles, with Purifi at the core to start? Seems reasonable enough...
The next consideration is the tweeter, and this is where the budget of the DIY operation gets tough, since the Purifi woofers and passive radiators already are pushing $1300. I think it just makes sense to go with a waveguide based tweeter like the KH 150 and the Sointuva, helps with directivity, alignment, and I like the aesthetics. Thanks to the work of augerpro, there are some tweeters that are available with a WG, like the Bliesma 25 and 34 ($$$$$) but the tried and true DXT from the ASR Directiva also works.
I'm no CAD wizard but I quickly whipped up my idea of a beautiful walnut baffle, which used 3/4" roundovers, chamfered woofer cutout on the back, waveguide cutout on the front, holes for 5mm t-nuts on the back to mount to a sturdy box and allow the baffle to be removed and swapped down the line. The back will be identical except the cutouts will be sized for 2 Purifi passive radiators and four binding posts at the very bottom. Simple enough, nothing crazy, would like to use a CNC to machine to walnut since one of my hands is no longer working. Baffle is 220mm wide, 418mm tall, 20mm deep.
This leaves the issue of a box, which probably has me the most worried in Phase 1. I've been reading multiple threads here, reading up on somasonus, looking at what KEF, Ascend, do for their boxes and right now I'm leaning towards a 6 sixed box made of vertical 3 ply bamboo 20mm thick, primarily because of Ascend Acoustics, and using CLD KEF bracing for the interior. I have an idea of what that would look like in reality, but I'm drawing a blank on what kind of glue, acoustic damping, resonance combatting I'd need to do to deal with walnut baffles.
Step 1: Part Selection - $1450 spent/$2800 total budget
Woofer: Pair of Purifi 6.5" $860 (already owned)
Passive Radiators: 4 Purifi PRs $460 (2/4 owned)
Tweeters: Undecided + Waveguide
DSP: MiniDSP 2x4HD $225 (already owned)
Amplifier: Undecided Class D
Cabinet Materials: Black Walnut lumber, vertical carbonized bamboo ply, CLD damping
Step 2: Cabinet Making
Cabinet: 3-Ply Verticall Carbonized Bamboo 30mm "Box"
Baffles: 25mm Black Walnut Lumber with Rubio Monocoat Finish
Bracing: Augerpro CLD 90% Overlap with Weicon Adhesive, Resonix applied to inner Panels
Miter: Traditional 45 degree, perhaps with 6.35mm Roundover on edges
Removable Baffles via Bamboo L-bracket glued to rear of baffle and then screwed into panel of bamboo via driver holes?
As of right now, it's actually the "inner cabinet" that has me the most worried. With the front and back walnut portions being removable, I can swap them in the future if need be, but I need to make the inner core be the foundation and be the permanent structure going forward. I am not sure if the bamboo is a good idea, I'm not sure how much it'll cost, and I'm not sure how to brace and damp it. Being one-handed, these issues need to be ironed out before getting too far ahead, since I can't really go into a workshop and experiment myself anymore. The DIYers here have been doing this for years, please chime in while the passive radiators are on order, tweeter selection is still up for grabs too.
I can always say eff it and sell the drivers I do have and just buy the KH 150's, but I'd like to give this a shot.
I'm going to treat this like an executable project, even if I don't go all the way and finish, which means deciding on parts, prices, cabinets, amps, DSP software, bracing, since all of that comes with the sticker price of the KH 150. We'll save the really hard part for later on, (measurements for the XO, in-room adjustments, near-field).
Some considerations, I think the KH 150s are all around solid, but I wouldn't call them beautiful per se. Beautiful to me is the Purifi 2 way Joachim Gerhard released a few years ago, see here: link. I really, really love walnut, so I'm immediately leaning towards a walnut baffle even though this might cause pains in the future for resonance. Another pain point, I'm thinking maybe I don't want to rebuild a cabinet every few years if I want to swap out drivers, maybe I like the idea of removing the baffle and driver swapping. This would be huge down the line for flexibility, and it means that in theory, I can do a sealed box, a passive radiator box, or a ported box in the future if I simply also swap the back baffle. So front and back removable walnut baffles, with Purifi at the core to start? Seems reasonable enough...
The next consideration is the tweeter, and this is where the budget of the DIY operation gets tough, since the Purifi woofers and passive radiators already are pushing $1300. I think it just makes sense to go with a waveguide based tweeter like the KH 150 and the Sointuva, helps with directivity, alignment, and I like the aesthetics. Thanks to the work of augerpro, there are some tweeters that are available with a WG, like the Bliesma 25 and 34 ($$$$$) but the tried and true DXT from the ASR Directiva also works.
I'm no CAD wizard but I quickly whipped up my idea of a beautiful walnut baffle, which used 3/4" roundovers, chamfered woofer cutout on the back, waveguide cutout on the front, holes for 5mm t-nuts on the back to mount to a sturdy box and allow the baffle to be removed and swapped down the line. The back will be identical except the cutouts will be sized for 2 Purifi passive radiators and four binding posts at the very bottom. Simple enough, nothing crazy, would like to use a CNC to machine to walnut since one of my hands is no longer working. Baffle is 220mm wide, 418mm tall, 20mm deep.
This leaves the issue of a box, which probably has me the most worried in Phase 1. I've been reading multiple threads here, reading up on somasonus, looking at what KEF, Ascend, do for their boxes and right now I'm leaning towards a 6 sixed box made of vertical 3 ply bamboo 20mm thick, primarily because of Ascend Acoustics, and using CLD KEF bracing for the interior. I have an idea of what that would look like in reality, but I'm drawing a blank on what kind of glue, acoustic damping, resonance combatting I'd need to do to deal with walnut baffles.
Step 1: Part Selection - $1450 spent/$2800 total budget
Woofer: Pair of Purifi 6.5" $860 (already owned)
Passive Radiators: 4 Purifi PRs $460 (2/4 owned)
Tweeters: Undecided + Waveguide
DSP: MiniDSP 2x4HD $225 (already owned)
Amplifier: Undecided Class D
Cabinet Materials: Black Walnut lumber, vertical carbonized bamboo ply, CLD damping
Step 2: Cabinet Making
Cabinet: 3-Ply Verticall Carbonized Bamboo 30mm "Box"
Baffles: 25mm Black Walnut Lumber with Rubio Monocoat Finish
Bracing: Augerpro CLD 90% Overlap with Weicon Adhesive, Resonix applied to inner Panels
Miter: Traditional 45 degree, perhaps with 6.35mm Roundover on edges
Removable Baffles via Bamboo L-bracket glued to rear of baffle and then screwed into panel of bamboo via driver holes?
As of right now, it's actually the "inner cabinet" that has me the most worried. With the front and back walnut portions being removable, I can swap them in the future if need be, but I need to make the inner core be the foundation and be the permanent structure going forward. I am not sure if the bamboo is a good idea, I'm not sure how much it'll cost, and I'm not sure how to brace and damp it. Being one-handed, these issues need to be ironed out before getting too far ahead, since I can't really go into a workshop and experiment myself anymore. The DIYers here have been doing this for years, please chime in while the passive radiators are on order, tweeter selection is still up for grabs too.
I can always say eff it and sell the drivers I do have and just buy the KH 150's, but I'd like to give this a shot.
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You're going to need assistance editing the reserved posts, I can help you with those when you're ready.
Interesting project. In my opinion, I think it is very possible to equal or exceed the performance of the Neumann KH 150 for less than $3500, if we account for the parts and material costs. Of course we have to assume we already own all the tools and measurement equipment, and because we do this for enjoyment, we don't assign a cost to our labor.
Some thoughts you may find useful...
Tweeter: I would give strong consideration to the SB26CDC + the @augerpro waveguide. He has developed multiple sizes of waveguide tailored to this particular tweeter and the results are excellent. I think we have to spend at least 3x the price to get something better. If a $500 tweeter is within the budget, then the Satori TW29BNWG-4 waveguide beryllium tweeter.
Baffles: If both the front and rear baffles are removable, we will need to put a lot of thought into how they are attached. The baffles, particularly the front baffle, must be firmly attached to the side/top/bottom panels and all interior bracing. The front baffle must be fully coupled to the rest of the cabinet. The front baffle must not be allowed to have its own vibration resonances because those would be very difficult to suppress or dampen. Using a dozen or so threaded fasteners could work, but this might destroy the aesthetic look of a smooth, clean walnut surface.
CLD: Augerpro has a thread where he developed very practical guidelines for CLD cabinet construction. Read through his guidelines before deciding on cabinet materials and construction techniques.
Solid wood construction: I have done solid wood baffles, and it turned out well.
https://www.diyaudio.com/community/threads/new-active-3-way-hypex-and-sb.352767/#post-6161813
Despite warnings about wood splitting due to humidity, the speakers are fine after 3 years. However, my baffles were not solid wood. I used a 3/4" birch plywood core, and then framed it with 3/4" thick mahogany, then added an outer layer of 3/4" mahogany. The plywood core stabilizes the resulting composite laminate, and restrains it from expanding across the grain.
This is a cool project. I look forward to seeing it progress !
Some thoughts you may find useful...
Tweeter: I would give strong consideration to the SB26CDC + the @augerpro waveguide. He has developed multiple sizes of waveguide tailored to this particular tweeter and the results are excellent. I think we have to spend at least 3x the price to get something better. If a $500 tweeter is within the budget, then the Satori TW29BNWG-4 waveguide beryllium tweeter.
Baffles: If both the front and rear baffles are removable, we will need to put a lot of thought into how they are attached. The baffles, particularly the front baffle, must be firmly attached to the side/top/bottom panels and all interior bracing. The front baffle must be fully coupled to the rest of the cabinet. The front baffle must not be allowed to have its own vibration resonances because those would be very difficult to suppress or dampen. Using a dozen or so threaded fasteners could work, but this might destroy the aesthetic look of a smooth, clean walnut surface.
CLD: Augerpro has a thread where he developed very practical guidelines for CLD cabinet construction. Read through his guidelines before deciding on cabinet materials and construction techniques.
Solid wood construction: I have done solid wood baffles, and it turned out well.
https://www.diyaudio.com/community/threads/new-active-3-way-hypex-and-sb.352767/#post-6161813
Despite warnings about wood splitting due to humidity, the speakers are fine after 3 years. However, my baffles were not solid wood. I used a 3/4" birch plywood core, and then framed it with 3/4" thick mahogany, then added an outer layer of 3/4" mahogany. The plywood core stabilizes the resulting composite laminate, and restrains it from expanding across the grain.
This is a cool project. I look forward to seeing it progress !
Baffles: all I can vizualize is a solid aluminum one. 1" Is the minimum.
Look where the structure Is weak: at the sides of the woofer (old speaker grills made with wooden frame and fabric Upon It used to break there BTW 😉 )
The baffle needs to be fastened, so threaded holes on aluminum ribs.
Look where the structure Is weak: at the sides of the woofer (old speaker grills made with wooden frame and fabric Upon It used to break there BTW 😉 )
The baffle needs to be fastened, so threaded holes on aluminum ribs.
The tweeter housing is another chapter.
Since It has a waveguide, one would want to incorporate it into the baffle.
Still remains the problem of solidly attach the tweeter flange( or without, because of the WG) to the baffle.
For me that's always a problem because for a state of the art execution the tweeter should be detached from woofer's box body, always.
Since It has a waveguide, one would want to incorporate it into the baffle.
Still remains the problem of solidly attach the tweeter flange( or without, because of the WG) to the baffle.
For me that's always a problem because for a state of the art execution the tweeter should be detached from woofer's box body, always.
What's the point of any of this if the parts cost is already $2800 without amps, tweeters, cabinet costs? 🤔
The question of this thread is already answered.
The question of this thread is already answered.
Yes. $3,500 should be enough to build about any speaker you can think of as long as you do enough of it yourself.
@planet10 is familiar with bamboo. I would suggest looking at constrained layer damping of the panels.
Bamboo plywood comes in a huge range of quality, so you can get crap MDF, crap, plywood, crap bamboo. And really good.
Stranded/fossilized bamboo ply is a very good speaker building material. Really stiff & hard. No need for any veneers just a bit more care with joinery.
We used plyboo.
dave
Stranded/fossilized bamboo ply is a very good speaker building material. Really stiff & hard. No need for any veneers just a bit more care with joinery.
We used plyboo.
dave
Recently I dismanted a pair of boxes from panasonic™
It's about 20x 10 x14 and its made of chipped wood ( classic). The wizzered 4" produced a lot of good bass ( the piezo tweeter delighted my ears with beautiful treble! ).
The problem was the extra plastic baffle that was put onto the woofer and fastened with 6 joints ( hot glue) to the wood ( false wood). That made a very rigid structure together with woofer's basket, so now that I opened a new page to visualize that Neumann active monitor, something reminds me of those panasonic I dismanted. There were also two flared-at-both-ends duct ports.
Just to say, it takes not very much expense to make some basic but working speaker: total cost of a loudspeaker in that way should be in the range of 10-15 $. The Neumann speaker just looks like that: CLD done industrially
It's about 20x 10 x14 and its made of chipped wood ( classic). The wizzered 4" produced a lot of good bass ( the piezo tweeter delighted my ears with beautiful treble! ).
The problem was the extra plastic baffle that was put onto the woofer and fastened with 6 joints ( hot glue) to the wood ( false wood). That made a very rigid structure together with woofer's basket, so now that I opened a new page to visualize that Neumann active monitor, something reminds me of those panasonic I dismanted. There were also two flared-at-both-ends duct ports.
Just to say, it takes not very much expense to make some basic but working speaker: total cost of a loudspeaker in that way should be in the range of 10-15 $. The Neumann speaker just looks like that: CLD done industrially
So you are already at 3,5k. What happened? Well, either you have shot over the goal with the driver selection i.e. surpassed the KH150 considerable (probably yes) or is it the industrial manufacturing that is so efficient that it is not possible for a private person to beat a commercial product cost wise given the same quality. I think you could meet the sonic results of the KH with perhaps 1/3 of the driver cost by getting e.g. the top their SB offering. Depending on your playing style, maybe you would like to look at the profi side of the product smorgasbord that constitutes the current available offerings. But as of now - I think you failed your mission by over-doing it.
//
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For $3500 (or even $2800), I could make a pair of active speakers which handily outperformed the KH150, but it would be larger, and it would be a 3-way.
Just off the top of my head:
Scanspeak discovery 10" woofer in sealed box ~ 30 liter
Satori MR13P midrange
SB 26CDC tweeter
Augerpro waveguide
Hypex FA123 plate amp
Parts cost per side is approximately $1000.
Assuming you want to continue with this project as you originally described... You already have most of the expensive items, so this is reasonable.
It may be that you will wind up with a total cost over the $3500 target. However, given the quality of the drivers, you should be able to exceed the KH150 both subjectively and objectively.
Thoughts?
j.
I can't tell from this angle whether it's any good, because they just FIRed one axis to within an inch of it's life.
OMG! The phase!! The phase @ 50 Hz rotates one round !
😆
And the bell is rather large! Can we talk about 'bell' in this case? So from 500 Hz the magnitude is regular and that's good!
BTW the reflex ducts that are angular like in the Neumann monitor...really sucks! Ah ah ah
😆
And the bell is rather large! Can we talk about 'bell' in this case? So from 500 Hz the magnitude is regular and that's good!
BTW the reflex ducts that are angular like in the Neumann monitor...really sucks! Ah ah ah
I did not listen to these monitors. The comrade who has the Hedds says that with the linearizer turned on they sounds "a little bit slightly better"))
OP can test this himself