[Duke]

The most expensive part of a speaker is usually the cabinet, and the bigger and higher efficiency the speaker is, the more this is true.   

But a considerable amount of money could be saved if I didn't have to build (or have built), crate, and ship a big cabinet.   If you build (or had a local woodworker build) the cabinet, well all of a sudden a lot of possibilities open up - your choice of wood, cabinet size/bass extension, whatever.  I would provide plans for two or three enclosure variations, which you could modify as needed.

This also opens up possibities to overseas customers, because most of the shipping cost would be eliminated.

Assume that high-quality prosound parts are used, and that I do my homework on the crossover. 

You can vote for more than one, but if you do, please post indicating which you find the most interesting. 

Thanks!

EDIT:  I added the 96 dB, 12" 8-ohm after the poll started, so if anyone wants to go back and add it or change their vote, they are welcome to do so.

[pslate]

This is an excellent idea Duke! Would you consider shipping assembled crossovers? I like the form factor of the Rhythm Prism, and the aesthetics of it as well. For me the 12" would be more tolerable to my better half.

[Duke]

This is an excellent idea Duke! Would you consider shipping assembled crossovers? I like the form factor of the Rhythm Prism, and the aesthetics of it as well. For me the 12" would be more tolerable to my better half.

I should have made that clear, my apologies.  Yes, the crossovers would be assembled and tested.  No soldering necessary, just woodwork. 

[Duke]

Let me give a little bit more description of the kit options, as the bare-bones descriptions in the poll leave a lot out.

The 98 dB 15" speaker could be completed as a satellite or as a fullrange speaker, with in-room extension to the mid 30's in the latter format, given a suitable enclosure.   Ballpark estimated cost is $850/pair for drivers + crossover + plans.   

The 93 dB 12" speaker could likewise be completed as a satellite or fullrange speaker, and it would be a bit more expensive, like maybe $950/pair ballpark. 

The 96 dB 15" 4-ohm speaker would go the deepest of the bunch (upper-20's in-room in a suitable box), but the tradeoff is that its midrange is not as refined as the 98 dB woofer.  $700/pair ballpark. 

The 96 dB 12" speaker wouldn't do very well as a full-range unless it was going to get a lot of boundary reinforcement.  $750/pair ballpark.

My personal preference would be the 98 dB 15" speaker.  It is something I have wanted to do for years in a finished speaker, but the box size, cost, and shipping nightmare always turned me away.

[JLM]

Could you provide rough cabinet design/sizes?

Ported, sealed, other?

I assume they would follow your home/pro designs, true?

Why would a 12 inch cost more than a 15 inch?

Oh, and how about subwoofer kits?

[opnly bafld]

This is an excellent idea Duke!

+1

Why would a 12 inch cost more than a 15 inch?

More expensive driver. 

[Duke]

Could you provide rough cabinet design/sizes?

Ported, sealed, other?

I assume they'd follow your home/pro designs, true?

I'd probably include plans for one stand-mount box and two floorstander boxes, one "reasonably small" and one big.  The following are just estimates:

For the 15" speakers (HxWxD):  Stand-mount,  25" x 17" x 15"; small floorstander,  44" x  17" x 13"; large floorstander 44" x 20" x 25".

For the 12" speakers (HxWxD):  Stand-mount:  22" x 14" x  13"; small floorstander, 44" x 14" x 12"; large floorstander 44" x 16" x 20"

They'd all be ported, but could be built as sealed boxes if your particular situation called for it (like, low-damping-factor tube amps + placement in or near the room corners).   In practice, if your port is the same diameter as a plumber's expandable test plug, it's easy to convert back and forth between ported and sealed, though you might want to add more stuffing in sealed-box mode. 

And yes, they'd be similar in format to what I've been doing for the past few years.

Why would a 12 inch cost more than a 15 inch?

More expensive woofer, higher parts cost on the crossover

Oh, and how about subwoofer kits?

A parts-only subwoofer kit would be pretty simple!  Woofer, plate amp, maybe a port.   Not really any place for me to add value, so I'd have to buy in large quantities to get my costs down low enough to be competitive and profitable, which would be a poor use of my limited resources.  In these two-way kits, I can add value though my crossover design.   Often the main hurdle facing the casual (or even serious) DIY guy is the crossover design, so that's where my window of opportunity lies.   

[JohnR]

Do you have a driver in mind for the 15" 98dB version?

[Duke]

Do you have a driver in mind for the 15" 98dB version?

Actually, I have two in mind.   I've worked with one already, and there's another that looks good on paper but I haven't tried it yet.   Not that there aren't many good high-efficiency 15" woofers out there, but I'm looking for a particular balance of characteristics in something that's not too expensive.   

That being said, I certainly haven't heard and probably haven't modelled everything out there.   So if you've found something you really like, feel free to mention it. 

[JLM]

Next question (and why I asked about doing a sub kit):

What F3 did you have in mind?

I'm also curious about crossover points/design (I know woofers that big start beaming at quite low frequencies).

Any chance of offering active kits?   

[FredT300B]

Duke, what do you think about a kit designed to fit in the PE birch trapezoidal flat pack enclosures?

http://www.parts-express.com/wizards/searchResults.cfm?FTR=birch+trapezoid&search_type=main&WebPage_ID=3&searchFilter=birch+trapezoid&x=41&y=3

[nullspace]

Hi Duke,

I voted for the 15"/ 98db version -- I'd buy your kit version of that speaker in a second.

Regards,
John

[sts9fan]

I am already planning on buying the 98db/15" kit. So you have to make it now.

[Duke]

Next question (and why I asked about doing a sub kit):

What F3 did you have in mind?

The F3 depends on how big a box you want to build.  For example, in a 2.5 cubic foot stand-mount box, the 98 dB 15" will go down to between 80 and 65 Hz (-3 dB), depending on how you tune it.   There are some advantages to tuning lower and having a higher F3, especially if subwoofage is involved.  On the other hand, in a 10 cubic foot floor-standing box, the same 15" kit will extend into the 30's (how far down into the 30's depends in part on how much boundary reinforcement we get).

I'm also curious about crossover points/design (I know woofers that big start beaming at quite low frequencies).

The crossover for the 98 dB 15" kit hasn't been designed yet.  Some juggling of tradeoffs is inevitable.  Note that most large woofers do not beam as badly as rigid piston theory predicts, because they do not behave as rigid pistons.   The 15" candidate woofer that I have worked with holds up considerably better than rigid piston theory predicts off-axis due to its cone design; the other one I haven't measured yet.   Its cone construction is different and so is the profile so I won't know until I measure it.

Any chance of offering active kits? 

Not in the forseeable future, sorry.  I don't want to be responsible for servicing DSP amplifier modules.

[Duke]

Duke, what do you think about a kit designed to fit in the PE birch trapezoidal flat pack enclosures?

http://www.parts-express.com/wizards/searchResults.cfm?FTR=birch+trapezoid&search_type=main&WebPage_ID=3&searchFilter=birch+trapezoid&x=41&y=3

YES!  That could definitely work! 

Now there are two modifications I would highly recommend to the PE trapezoidal boxes:  First, remove the lip from around the front baffle.  It would be a source of cupped-hands coloration.  Second, brace the narrow area between the woofer cut-out and where the horn cut-out will be, so that the front baffle won't have a weak spot. Of course you can brace more than just that area, but that would be my top priority.

[Duke]

Hi Duke,

I voted for the 15"/ 98db version -- I'd buy your kit version of that speaker in a second.

Regards,
John

I am already planning on buying the 98db/15" kit. So you have to make it now.

Okay guys, I'll get working on it!!

[Russell Dawkins]

Hmmm!

This has got me thinking - a pair of the 98dB 15s with the Ncore amps spoken of recently could provide some sort of ultimate bang - for - buck...

[CometCKO]

Hi Duke,
Late to this poll.  George Short of North Creek used to offer a range of speaker designs as kits.  His core expertise was in crossover design, and the crossovers were things of beauty.  As I remember, he had a local cabinetmaker lined up to offer pre-built cabinets for those who didn't want to do the assembly.  I built a couple of his speaker kits, a pair of which still sit in my living room.  Anyway, if you know George, you could check with him about his experiences doing this.  He was quite helpful to his DIY customers, and I think it was a fun part of his business for a while.  But he did quit, so it might be worthwhile talking to him about his reasons.  Not trying to discourage you -- quite the opposite, in fact.  Knowing what you are getting into might help you get the most out of it!

Hope this helps!

Frank

[Duke]

Hi Duke,
Late to this poll.  George Short of North Creek used to offer a range of speaker designs as kits.  His core expertise was in crossover design, and the crossovers were things of beauty.  As I remember, he had a local cabinetmaker lined up to offer pre-built cabinets for those who didn't want to do the assembly.  I built a couple of his speaker kits, a pair of which still sit in my living room.  Anyway, if you know George, you could check with him about his experiences doing this.  He was quite helpful to his DIY customers, and I think it was a fun part of his business for a while.  But he did quit, so it might be worthwhile talking to him about his reasons.  Not trying to discourage you -- quite the opposite, in fact.  Knowing what you are getting into might help you get the most out of it!

Hope this helps!

Frank

I don't know George, sorry, but do remember North Creek Audio kits.     

Wayne Parham offers high-efficiency kits, and Earl Geddes did for a while.  I don't think it has been the path to riches for anyone, but I'm just hoping for a few bucks on the side.  Also with the 98 dB 15" kits, I'm able to do something that just wouldn't be practical if I had to build and ship them as completed speakers. 

Today I received the promising-looking 15" woofer that I hadn't used before, and I like what I'm seeing in my preliminary measurements.  No hidden nasties, and if anything its response "leans" in the right direction for what I want to do.  Hope to have time this weekend to start on the crossover. 

[JLM]

Doubt if you could find existing pre-built cabinets to fit 12 inch designs let alone 15 inchers.  But pre-cut flat panels could be a niche for an out of work cabinet builder.  With a day or two notice a pair of kits should be able to be provided.