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

[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.

[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?

[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.

[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.

[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.

[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?

[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...

[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.

[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?

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

[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?

[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

[lorenmjones]

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

BDS puts the -3db of baffle step at 150 and starting at 300.
Here is a BDS graph

So perhaps we lose a couple db from the woofer and a couple db from the mid? I understand baffle loss if it occurs in the middle of the passband of a midbass in a 2 way. I don't clearly understand how it is managed if it occurs in the midst of the crossover region.

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

[jhollander]

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

Reading the graph it's -7 to get flat at 20 hz.

[jhollander]

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

Here's a pic of a 3 way with the raw driver responses. The low woofer response is not accurate below 80 hz due to the test enclosure