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

[lorenmjones]

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

True enough on the baffle part.

Perhaps two variants are in order here from the outset if the one will not compromise the other. A shorter slightly smaller volume monitor variant with a rotatable baffle and a taller more tower style design with 25% more volume and a few hz of extra bass extension.

I would think if the baffle width were held constant both designs should require the same crossover. I don't know how the crossover is affected by the rotated baffle idea.

I again must defer to folks with crossover experience.

You would just need a perfectly square (or round) removable baffle for the TM chamber only. Four t-nuts/bolts and some gasket tape is all it takes.

Edit: Think big JBL reference monitor

https://www.jblpro.com/www/products/...series/lsr6332

[jhollander]

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

OK, assuming we can trust the MFR FR plots to be close to accurate the 6Fe100 sensitivity at 200 to 300 hz is right at 90 db just the same as the ST305 at the same frequency.

Is that enough sensitivity from the mid or do we need to look for one with at least 92 to 93 db?

Where are you thinking the baffle step is going to drop the woofer sensitivity to?

[Jay1]

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

If you want to do this you need to talk to Dave Pellegrene. Pretty much a different project altogether than the one being discussed in this thread. I think it is an awesome concept.

You would just need a perfectly square (or round) removable baffle for the TM chamber only. Four t-nuts/bolts and some gasket tape is all it takes.

Edit: Think big JBL reference monitor

https://www.jblpro.com/www/products/recording-broadcast/lsr6300-series/lsr6332

[lorenmjones]

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

If you want to do this you need to talk to Dave Pellegrene. Pretty much a different project altogether than the one being discussed in this thread. I think it is an awesome concept.

http://techtalk.parts-express.com/sh...ighlight=audax

Those sort of dimensions but not with the tweeter between the woofer and midrange. By rotatable I meant the tweeter and midrange mounted on a removable square baffle that can be rotated 90 degrees so that the speaker can be used on it's side. It also makes it easier to play with waveguides, different drivers, crossover, etc...

[Jay1]

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

Those sort of dimensions but not with the tweeter between the woofer and midrange. By rotatable I meant the tweeter and midrange mounted on a removable square baffle that can be rotated 90 degrees so that the speaker can be used on it's side. It also makes it easier to play with waveguides, different drivers, crossover, etc...

That would be a pretty nice feature for sure, would make them usable for center channel duty as well. It would just require a slightly larger cab, internal chamber has to include full TM height.

[andy19191]

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

Think 15" w x 29" h x 16" d with the top 5" given to the mid in a WTM alignment.

Those sort of dimensions but not with the tweeter between the woofer and midrange. By rotatable I meant the tweeter and midrange mounted on a removable square baffle that can be rotated 90 degrees so that the speaker can be used on it's side. It also makes it easier to play with waveguides, different drivers, crossover, etc...

[lorenmjones]

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

OK, assuming we can trust the MFR FR plots to be close to accurate the 6Fe100 sensitivity at 200 to 300 hz is right at 90 db just the same as the ST305 at the same frequency.

Is that enough sensitivity from the mid or do we need to look for one with at least 92 to 93 db?

[Jay1]

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

I think the ST305 makes a solid choice. Dont see the need to aim much below 30hz all things considered. The idea of a large monitor makes sense from a portability and WAF standpoint. It would be less visually dominating even though the same footprint is needed. Either way the ST305 could easily work in 75L tuned to 33hz f3/f6 36hz/30hz. Think 15" w x 29" h x 16" d with the top 5" given to the mid in a WTM alignment. Easy to build, easy to move, easy to stash somewhere when the wife yells at you.

[andy19191]

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

But again, there's all of that available space under them........from a DIY standpoint why not take advantage of it?

Because you want the flexibility in placement that a luggable speaker brings particularly if you can rotate the tweeter and midrange.

In UK I assume you have some income tax on top of VAT?

Yes there is direct taxation at a lower rate than in Germany but there are more indirect taxes in the UK. If you are rich live in the UK and if poor live in Germany.

An interesting modern diy take on your concept might be one with built in amps and minidsp. That would kill the budget but would certainly allow you to control the tone in different placements.

I have been working off and on on a more expensive active version and the activity here prompted thoughts about a budget passive version.

[lorenmjones]

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

Andy,

That makes sense re: people's perceptions from the previous thread. My initial thought process may have initially had a mild misinterpretation of the monkey coffin term. VAT is painful. I spent three years in Germany so I experienced it. In UK I assume you have some income tax on top of VAT?

In any case I think the ST305 in my mind is going to be a nice combination of sensitivity, LF extension and 8 ohm impedance at the right price for this project in the tower forms actor.

An interesting modern diy take on your concept might be one with built in amps and minidsp. That would kill the budget but would certainly allow you to control the tone in different placements.

[Mayhem13]

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

I think the deviation from the classic three way monitor has been for the sake of deeper bass extension.....or possibly the perception of what that is. I agree about the SQ of those designs you mention,.......the were great and drums were are real joy with the midbass slam. But again, there's all of that available space under them........from a DIY standpoint why not take advantage of it?

[andy19191]

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

Well that makes sense and I think what it looks like we are aiming at is a bit of a compromise.

When the topic started in the previous thread I, and I suspect a few others, had a clear idea of a big monitor from the 70s (Sansui, Pioneer, JBL,...) but the design has not evolved in this direction. Fair enough. I am continuing along the big monitor path and perhaps it would be better if I stopped talking about it and restricted my comments to a floor standing tower.

The only one of your monitor criteria that would fall short on would be the sensitivity by 1-2 db.

If the monitor is pulled out into the room and placed on stands then this may be true but perhaps not when it is placed against a wall on a sideboard or at 45 degrees in the corners of a narrow room. Getting on top of how this sort of thing might be handled with pots and/or switches is an interesting part of the design for me.

Also your budget at 500 pounds for parts is quite a bit higher than $400. But I do know some parts are pricier there.

20% of that price is VAT tax, it includes the plywood and bits and bobs and prices before tax tend to be 5-10% more expensive. I think we are quite close in terms of the hardware the budget will buy.

[lorenmjones]

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

Well that makes sense and I think what it looks like we are aiming at is a bit of a compromise. ST305 woofer is more sensitive than some other possibilities but prob won't give 92 db, and it's F3 is at 29 as I am modeling it currently. I would think this design could be built in a shorter "monitor" shape box and still easily give you an F3 of 32 or 33 hz with 90 or 91 db sensitivity and adequate power handling to sustain 110 db or a little better. The only one of your monitor criteria that would fall short on would be the sensitivity by 1-2 db. I think you will need to spend a bit more on a woofer that can really give you 92 db, and F3 of 35 in 70 liters. Again there certainly could be drivers under $100 that will do that but I just don't know which. Also your budget at 500 pounds for parts is quite a bit higher than $400. But I do know some parts are pricier there.

For a monitor: target sensitivity about 92dB 8 ohm, F3 about 35Hz ported, box size about 75 litres, SPL of 115dB but settle for >110dB, price £500 total. The woofer at the moment is the ST305-8 despite the price problem but I am looking for an alternative.

For a big floor standing tower: I would want more bass extension, accept less efficiency, easy load less important, accept bigger box, SPL about the same, high fidelity response more important, price perhaps a bit higher because more likely first rather than second speaker. Target sensitivity 89dB 4 ohm, F3 25Hz ported, box size about 125 litres, SPL >110dB, price £600. The ST385-8 15" looks about right but in truth I have not looked closely because, although of interest, I do not intend to build such a speaker in the near future.

[andy19191]

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

Andy, what sensitivity and LF extension would you have in mind for this sort of speaker? What woofer would you suggest to meet that goal since woofer will determine sensitivity of the system.

For a monitor: target sensitivity about 92dB 8 ohm, F3 about 35Hz ported, box size about 75 litres, SPL of 115dB but settle for >110dB, price £500 total. The woofer at the moment is the ST305-8 despite the price problem but I am looking for an alternative.

For a big floor standing tower: I would want more bass extension, accept less efficiency, easy load less important, accept bigger box, SPL about the same, high fidelity response more important, price perhaps a bit higher because more likely first rather than second speaker. Target sensitivity 89dB 4 ohm, F3 25Hz ported, box size about 125 litres, SPL >110dB, price £600. The ST385-8 15" looks about right but in truth I have not looked closely because, although of interest, I do not intend to build such a speaker in the near future.

[lorenmjones]

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

Andy, what sensitivity and LF extension would you have in mind for this sort of speaker? What woofer would you suggest to meet that goal since woofer will determine sensitivity of the system.

For the less sensitive design Loren seems to be working towards not much. For a more sensitive, easy to drive, big monitor with the flexibility (i.e. pots and/or switches) to be placed against a wall then approaching the 4.1 ohms of the "Rockin It Old School" monitor is the concern. Since there are alternative tweeters that do not have a low impedance, have a few dB less sensitivity to be closer to the woofer, can handle the power, possibly with a bit of waveguide loading and are close enough in price then picking one seems the right move.

Has picking drivers from PE become one of the objectives?