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

[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.

[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.

[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.

[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?

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.

[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.

[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.

[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?

[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?

[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.

[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.

[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?

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

On your mid sensitivity you can pick up 2-3 db from the slopes of adjacent drivers and 3 db from the baffle depending on the width. I use woofer(s) minus 3 db baffle step as the lowest for the mid when I'm contemplating.

[thekorvers]

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

As far as the tweeter impedance goes I am no crossover designer so I could be wrong, but my thought was that the very sensitive tweeter would have some series resistance in front of it anyway and so would be unlikely to really present a 4 ohm load to any amplifier. I could be wrong on this as well, but I was thinking that a little lower impedance at tweeter frequencies would be less of a problem for even more anemic home audio gear. As far as valve amps, I doubt that the average guy who would build a speaker like this would be using a valve amp, but I could be wrong. With that said, I am not attached to the tweeter. I chose it for a decent looking FR, good sensitivity, good power handling and good price but I am open to other choices for sure.

You are absolutely right.

[jhollander]

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

On your mid sensitivity you can pick up 2-3 db from the slopes of adjacent drivers and 3 db from the baffle depending on the width. I use woofer(s) minus 3 db baffle step as the lowest for the mid when I'm contemplating.