Is there interest in a large three way "monkey coffin" collaboration?

[Mayhem13]

Re: Is there interest in a large three way "monkey coffin" collaboration?

A baffle wide enough to support a 12" woofer would leave a need for 3-4db of BSC depending primarily on the midrange chosen response. The woofer should absolutely be the efficiency limiting factor in a classic big box speaker.

A 12" woofer is certainly more practical

[lorenmjones]

Re: Is there interest in a large three way "monkey coffin" collaboration?

I would like a 15 as well. The DC380 hits all the marks for box size, efficiency, good extension sealed but lacks excursion. The ST305 is right in the sweet spot for this build. Thanks for the suggestion andy19191.

There are prosound 15's that will play down into the low 20's and have 91db efficiency or even better, but they (B&C, AE) cost a ton of money.

Personally, I would have liked to have seen 15's. But what we really wanted was 30 Hz, 92dB/W, and 8 ohms. And 15's are either high 80's that go deep in a huge box or mid 90's that only get to 40 (PA). This isn't the frist time I couldn't find 'the perfect 15' and punted to a 12. That s2 12" certainly splits the difference perfectly. These are going to end aup a lot like my first 'serious' non-PA speakers - 12" Ultimate car subs (old prototype of the current Series 2, actually), the old B11EC80 mid, and a slightly horn loaded dome tweet. Probably with a lot better crossover.... The tools we have now are better than back in the late 80s. I remember mesauring crossover responses with oscilloscopes and tweaking reverse phase nulls in by ear with a sine generator.

[jhollander]

Re: Is there interest in a large three way "monkey coffin" collaboration?

So in this case the lowest sensitivity mid you would consider with our 92.5 db woofer would be 89.5 db?

Yes, but check the graph of the woofer, 92.5 could be the average. I seem to recall when I looked at the Dayton you linked earlier it was around 89 or 90 around 100 hz.

[jhollander]

Re: Is there interest in a large three way "monkey coffin" collaboration?

The DC380 hits all the marks for box size, efficiency, good extension sealed but lacks excursion.

Does that mean you have a SPL target also?

[lorenmjones]

Re: Is there interest in a large three way "monkey coffin" collaboration?

Not any absolute one in mind. I figure a listening distance of 3 meters which is theoretically 9.5 db. I also figure that a listening level of 95 db for a song or two when you really want to rock and feel the music is about as loud as most folks would go. Many probably wouldn't go to that level. Add 6 db of crest factor for fairly compressed sources and you are at 110 db approximately. So I think 110 db across the range is a reasonable target for a speaker of this style.

I was just modeling again with the DC380 and it will give a pretty decent response sealed but down low it only manages less than 100 db at 30 hz. In a vented box it does some better but the box gets really big. Are your DC380's sealed or vented?

I didn't have an actual target in mind honestly. I'm just spitballing in this post. Do you have any thought on it? I will not rarely listen to a song or two where the level at the listening position is in the 100 db range (meter on fast). I never listen that loud for very long.

Does that mean you have a SPL target also?

[andy19191]

Re: Is there interest in a large three way "monkey coffin" collaboration?

Well it looks like I am officially surprised since at this point in time the votes are 3:1 in favour of a floor standing tower speaker rather than a monitor. Opting for sensitivity over bass extension and then not going for the type of speaker that (I thought) had initiated this thread seems odd to me. My interest is in a cheap, efficient, easy to drive monitor but most of the remaining objectives are still shared.

The European distributor for Dayton Audio wants €147.20 ($200.04) for the ST305-8 compared to the PE price of $94.80 and the advertised list price of $129.99. I could probably argue the price down a bit but it is the reason you see few European builds using Dayton drivers.

[Whitneyville1]

Re: Is there interest in a large three way "monkey coffin" collaboration?

I did some messing with numbers at work today, and for the money we're talking about, a 15" woofer of good quality and high sensitivity breaks the bank. A really good solution, but a budget buster is the 12" Series II with a passive radiator. The builder could adjust the added weight to his/her taste of bass extension/bass output/bass SQ. Dual 12's would work, sound, and look great in shoulder high columns. Those aren't options, but basically a 3-way Paul Carmody's "Classix III" with 2/3+ octave more bass, a little more mid-range definition, and just a bit more sensitivity is my thinking. In the XO design, the mid-range voicing can be adjusted to suit the builder's taste. Very laid-back, "normal" or very revealing. The L-Pad on the tweeter should be a very easy adjustment for room acoustics. The old rotary L-Pads almost never have the correct "taper" ratio to do a first class job. If these can be done for $500 a pair less cabinet materials and finishing (you can get scraps for inside bracing then spend $800 a speaker for veneer), this project should get some traction.

[lorenmjones]

Re: Is there interest in a large three way "monkey coffin" collaboration?

Wow, I am shocked at the price of the Dayton woofers in Europe. It would be cheaper to have one of us in the US buy them and ship to you, but still fairly pricey I suppose. Who makes comparable lower price/higher value drivers in Europe? Visaton? Entry level Peerless?

Well it looks like I am officially surprised since at this point in time the votes are 3:1 in favour of a floor standing tower speaker rather than a monitor. Opting for sensitivity over bass extension and then not going for the type of speaker that (I thought) had initiated this thread seems odd to me. My interest is in a cheap, efficient, easy to drive monitor but most of the remaining objectives are still shared.

The European distributor for Dayton Audio wants €147.20 ($200.04) for the ST305-8 compared to the PE price of $94.80 and the advertised list price of $129.99. I could probably argue the price down a bit but it is the reason you see few European builds using Dayton drivers.

[lorenmjones]

Re: Is there interest in a large three way "monkey coffin" collaboration?

It is around 90 at 300. The 92.5 spec is probably based on some of the peakiness up toward the top of it's "useful frequency range" I would guess. The FR graphs from Dayton stipulate that under 200 hz they are invalid.

Yes, but check the graph of the woofer, 92.5 could be the average. I seem to recall when I looked at the Dayton you linked earlier it was around 89 or 90 around 100 hz.

[lorenmjones]

Re: Is there interest in a large three way "monkey coffin" collaboration?

I like the ideas regarding crossover options to adjust voicing. Adjustable LPads may be cool, or it could be as simple as suggesting a couple different options for tweeter and midrange attenuation and perhaps an option for different BSC levels. I am not a crossover designer so I will have to rely on others for that; I want to participate in the design process on this though so I can begin to learn about crossover work.

As far as the bass tuning idea with a PR, I think you could do the same thing with a couple of different vent lengths. There could easily be suggestions for a slightly smaller cabinet tuned a little lower that give a little gentler rolloff such that F3 is around 40 but F6 still in the 20's. Any builder could choose that if they felt it integrated better with their room than a standard "max flat" alignment.

I did some messing with numbers at work today, and for the money we're talking about, a 15" woofer of good quality and high sensitivity breaks the bank. A really good solution, but a budget buster is the 12" Series II with a passive radiator. The builder could adjust the added weight to his/her taste of bass extension/bass output/bass SQ. Dual 12's would work, sound, and look great in shoulder high columns. Those aren't options, but basically a 3-way Paul Carmody's "Classix III" with 2/3+ octave more bass, a little more mid-range definition, and just a bit more sensitivity is my thinking. In the XO design, the mid-range voicing can be adjusted to suit the builder's taste. Very laid-back, "normal" or very revealing. The L-Pad on the tweeter should be a very easy adjustment for room acoustics. The old rotary L-Pads almost never have the correct "taper" ratio to do a first class job. If these can be done for $500 a pair less cabinet materials and finishing (you can get scraps for inside bracing then spend $800 a speaker for veneer), this project should get some traction.

[djg]

Re: Is there interest in a large three way "monkey coffin" collaboration?

4400 views in less than a week, popular thread.


I originally was for a short cab, then I remembered my lost JBLs. Voted big in the poll.

[Mayhem13]

Re: Is there interest in a large three way "monkey coffin" collaboration?

I'm not sure I get your concerns over Xmax where the DC380 is concerned.

[jhollander]

Re: Is there interest in a large three way "monkey coffin" collaboration?

I ran the DC380’s sealed. There’s a large FR hump less than 100 hz that brings up the response. They certainly did not require a sub and could do 105 db.

My opinion is to design for continuous operation at 100 db for home use but that’s me.

As long as we’re giving opinions seems like if you set the baffle width a person could make either a monitor or tower. A 15 inch woofer is the classic large speaker, but it sure limits the design possibilities.

Have you set a budget? If you make this $200 a pair for the drivers the list gets much shorter (not that I would set it that low). Give those who are building two votes…

[isaeagle4031]

Re: Is there interest in a large three way "monkey coffin" collaboration?

John the budget is $400 for drivers and crossover parts (I think)

[lorenmjones]

Re: Is there interest in a large three way "monkey coffin" collaboration?

Well, it looks like the poll regarding form factor is pretty decisive so that question is answered.

And I think we have settled on the ST305 woofer in around 80 to 100 liters vented. With that woofer and with the target budget of $400 I think the budget for the mid is probably in the $40 to $45 range and for the tweeter in the $25 to $30 range. That leaves $75 for crossovers which will be tight and would necessitate iron core inductors and NPE caps at least for the woofer lowpass and midrange high pass. Still I think it is do-able while sticking close to that $400 target for parts.

So I wanted to throw a couple midrange drivers out there for people to consider and comment on. It seems like the only HiFi type mids with adequate sensitivity and power handling are too expensive (like the Scan Disco 15M4624G which looks tasty but is $70). Perhaps I am missing some other options though...anyway here are the suitable alternatives that I found.

There is this Faital that looks awesome except for it's octagonal frame. Very smooth FR but the breakup comes in a little low at like 3.7k. Perhaps it could be rearmounted with a little roundover on the front edge of the opening to minimize diffraction problems from rear mounting?

http://www.parts-express.com/faitalp...-ohm--294-1150

Then there is this Faital which has a little more ragged response with that 5 db wiggle from 1k to 2k but is round and has more than enough sensitivity and power handling. It is but*-ugly though.

http://www.parts-express.com/faitalp...-ohm--294-1152

This Celestion has plenty of sensitivity and power handling. It too is a little ragged from 800hz to 2k and has a breakup starting at 3.5k. It does have a round frame and looks better than the Faital 6FE200.

http://www.parts-express.com/celesti...-ohm--294-2052

Frankly I think I might favor the 6FE100 Faital because of it's smoother response and because it looks less like a really cheap PA speaker. Please chime in with thoughts on these drivers or suggestions for others.

Oh, and HAPPY FOURTH OF JULY!! God Bless the USA!!