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

[lorenmjones]

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

That would make a cool garage speaker

I was looking at some cheap woofers last night. Cheap woofers tend to have a very high Qts. I don't know how the bass sounds on a speaker with a high Q driver, if they have a relatively flat response. One that I modeled had a peak of about 3 dB at 40 hz in a sealed box. The sensitivity was 84 dB. My first thought was that this driver could be used in a "cheap" 3-way. Not suggesting it for this build, but maybe for a lower cost build. The sensitivity was low enough to allow something like an RS100P, or RS150P to be used as a mid. That would allow a cheap tweeter as well, since it could easily cross around 3k. The driver is the GRS 12PR-8, and is just under $20.

[andy19191]

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?

The price of drivers in Europe is usually a bit more than US price plus tax. It would be interesting to know why Dayton drivers have such a large markup they lose their good value status. Unlike some, Intertechnik is a solid DIY speaker company which invests in providing good support such as their Loudspeaker Building Magazine.

The problem is finding cheap big monitor woofers. There are plenty of cheap efficient PA woofers with no bass, plenty of cheap subwoofers with bass and no efficiency and plenty of expensive 12" woofers with the right efficiency and bass.

Yes, I don't know anything about rotary control L-Pads, but they seem distinctly not "hi-fi" to me. Pots always get scratchy over time etc.

I suspect this is another indication that you are receiving input about different kinds of speakers.

[djg]

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

I would love to see something done with the GRS 12PR-8 or GRS 12PF-8.

http://techtalk.parts-express.com/showthread.php?234899-Paging-Johnny-Richards-(Le-Singe-Sarcophage)&highlight=sarcophage

http://techtalk.parts-express.com/showthread.php?224467-Le-Singe-Sarcophage-A-large-GRS-based-3-way&highlight=sarcophage

[Beau]

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

I was looking at some cheap woofers last night. Cheap woofers tend to have a very high Qts. I don't know how the bass sounds on a speaker with a high Q driver, if they have a relatively flat response. One that I modeled had a peak of about 3 dB at 40 hz in a sealed box. The sensitivity was 84 dB. My first thought was that this driver could be used in a "cheap" 3-way. Not suggesting it for this build, but maybe for a lower cost build. The sensitivity was low enough to allow something like an RS100P, or RS150P to be used as a mid. That would allow a cheap tweeter as well, since it could easily cross around 3k. The driver is the GRS 12PR-8, and is just under $20.

I would love to see something done with the GRS 12PR-8 or GRS 12PF-8.

[jhollander]

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

I think a decent x-o for a three way is about $90 pair $45 each, that could go to $100 easy if the x-o for the woofer goes to 300 hz.

Again just an opinion, if you have to skimp on quality do so on the woofer, buy a decent mid or two

[lorenmjones]

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

I think 100 db at 1 meter for home use is a very reasonable output level to shoot for. Take away 6 to 8 db for distance to listening position and 8 to 10 db for transient peaks and you have a comfortably loud listening level of 85 db or so. I doubt too many of us listen louder than that very often. But I can certainly say that in general a speaker running within a couple db of its max level doesn't sound as effortless as one running 10-15 db below it's maximum capability.

I'm very open to DC380 or the ST305. Perhaps another poll is needed.

And certainly a builder could easily shorten the baffle and increase the cabinet depth to accommodate the required volume thus building a short monkey coffin version if they prefer it over the tower monkey coffin. Also the builder can adjust the volume and LF tuning to taste as long as they keep baffle width the same (as you noted).

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…

[rpb]

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…

I was looking at some cheap woofers last night. Cheap woofers tend to have a very high Qts. I don't know how the bass sounds on a speaker with a high Q driver, if they have a relatively flat response. One that I modeled had a peak of about 3 dB at 40 hz in a sealed box. The sensitivity was 84 dB. My first thought was that this driver could be used in a "cheap" 3-way. Not suggesting it for this build, but maybe for a lower cost build. The sensitivity was low enough to allow something like an RS100P, or RS150P to be used as a mid. That would allow a cheap tweeter as well, since it could easily cross around 3k. The driver is the GRS 12PR-8, and is just under $20.

[Sydney]

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

...but they seem distinctly not "hi-fi" to me. Pots always get scratchy over time etc...

Bingo...They get erratic and prone to failure ( I know I've replaced more than a few in repairing cabs for others )

[lorenmjones]

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

That was the (somewhat arbitrary) target. It is not a hard and fast number.

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?

Yes, I don't know anything about rotary control L-Pads, but they seem distinctly not "hi-fi" to me. Pots always get scratchy over time etc.

I would favor just some suggestions for crossover variations that the builder can try before finalizing which version of mid and tweeter level they prefer. But selector switches would be a nice option if the person wanted to spend the extra cash for that.

Personally I'd forgo L-Pads in favor of selector switches with different value resistors for attenuation.

[lorenmjones]

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

Well I may be off base there.

I do think the DC 380 would work well here. Sealed box of 100 liters with walls lined gives F3 of 42, F6 of 32 and F10 of 24. That may integrate well with a lot of rooms. They will handle 35 watts in that box before exceeding excursion at 30 hz. The output above 100 hz at that level is 106db. All this according to WBCD. I guess if you calculate in room gain then the output at 30 hz with that input will probably be at least equal to the 106 db it will do above 100 hz with that power. This simulation seems to match jhollander's experience using them. I am sure we could do well with them and they are cheaper...it could free up money for a nicer mid, or just keep the overall budget down a bit.

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

[Sydney]

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

...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. ...

Personally I'd forgo L-Pads in favor of selector switches with different value resistors for attenuation.

[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!!

[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)

[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…