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

[joeybutts]

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

Thanks Joey. Perhaps I'll find a time that works for you to come by and check them out.

Yeah, just let me know.

I messed with it tonight on the way to pick up dinner. I cut off the subwoofer, set the crossovers at 63/4k and set the slopes to 18db/12db. No EQ.

Now of course this is based on being in the truck, so take it for what it is worth to you. Clean, clear, face melting volume. I don't notice any distortion up to the point I feel is loud....which...knowing me....is loud. :D Definitely not laid back, but I think that is typical of most PA drivers.

I'm probably missing a lot in reviewing but feel free to ask me for more details if you like.

[lorenmjones]

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

Thanks Kim,

Here is BDS (JeffB's tool) for a 42 x 15 baffle with woofer 12 inches from floor. They are 3 ft out from rear wall and a few feet from side walls.




Impressive how much room gain there is in the bottom octaves, but in many houses with open floor plans that room presurization may not happen as much I think. Anyway this is a side discussion at this point, but one I want to continue to understand more.

Post some graphs. Bass with infinite baffle vs bass with 15 x 42 baffle.

You should see the deep bass drop 6 dB. The drop starts around 1k for little boxes, and drops the full 6 dB by about 100 hz. The drop maybe starts around 400 hz on a bigger baffle. (Guessing 400 hz.) The deepest bass still should drop 6 dB relative to an infinite baffle. The midrange driver will show a drop in bass as well starting around 400 hz. That's OK, we plan to roll it off there anyway. Above that starting point, its sensitivity should be the specified half space value, so an 89 dB mid will be 89 dB in the 400 hz to 3k range. If the mid and woofer both start out as 89 dB, the woofer will drop to 83 dB down low. That would leave the mid too loud to match up with the woofers reduced output, unless it is padded down. But... if the woofer is placed near a boundary like the floor, or wall, or both, its output gets boosted back up. The exact amount is uncertain (uncertain to me anyway), but it could be more than 6 dB. Placing the woofer farther away from the boundaries reduces the amount of boost. Ideally, we don't want the woofers 100 hz to 400 hz range boosted more than 6 dB by the speakers position in the room. If it is boosted much more than 6 dB, we need a more sensitive mid, or two mids to match its boosted output. If the speakers are positioned 4 or 5 feet from the walls, and if the listening seats are not against the wall, a single mid is probably just the right sensitivity, especially if the woofer is about 20" off the floor. There is software (maybe JeffBs) that lets you check this for differing room sizes, and locations.

Baffle step compensation.... BSC... is just that. Its compensating for the reduced bass that is allowed by the baffle.

[lorenmjones]

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

Cool. Thanks Joey. Yes, based on your relaxed listening level when you drove up to your house the other day while I was sitting there I would have to take your word for it when you say LOUD!

I'm thinking that Faital mid will be a very solid choice.

Yeah, just let me know.

I messed with it tonight on the way to pick up dinner. I cut off the subwoofer, set the crossovers at 63/4k and set the slopes to 18db/12db. No EQ.

Now of course this is based on being in the truck, so take it for what it is worth to you. Clean, clear, face melting volume. I don't notice any distortion up to the point I feel is loud....which...knowing me....is loud. :D Definitely not laid back, but I think that is typical of most PA drivers.

I'm probably missing a lot in reviewing but feel free to ask me for more details if you like.

[lorenmjones]

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

Those look super cool? Love them.

They are 12 inch woofers. Probably 30 inches tall--I'm away from my house for a few days or I'd measure. The original specs of those are high efficiency at the expense of that real low bass. I currently use them as L/F in my home theater system. I'm sure I could find or build something with better sound quality than 40 year old speakers, but I love how they look and just the whole ambiance that vintage speakers bring to a room.
[ATTACH=CONFIG]48180[/ATTACH]

[lorenmjones]

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

Maybe we should be monitoring your thread! That should be a cool project though.

This should make for an interesting comparison, as I am doing something similar (not the same though!). My first HiFi exposure was my uncle's system using the Boston Acoustics A150 Series III. Attached pic for reference:

[ATTACH=CONFIG]48179[/ATTACH]

I am going to make a new version of this I'm simply calling the '1500' using almost the same box and layout. Dayton DA270-8 10" on the bottom (sealed), ? mid, and originally the Vifa DX25 for a tweeter.

Needless to say, I've been monitoring this thread

[JasonP]

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

Thanks Kim,

Here is BDS (JeffB's tool) for a 42 x 15 baffle with woofer 12 inches from floor. They are 3 ft out from rear wall and a few feet from side walls.

[ATTACH=CONFIG]48184[/ATTACH]
[ATTACH=CONFIG]48185[/ATTACH]

Impressive how much room gain there is in the bottom octaves, but in many houses with open floor plans that room presurization may not happen as much I think. Anyway this is a side discussion at this point, but one I want to continue to understand more.

Yes, lots of gain. In my project I am targeting no BSC at all actually, and my baffle will be 32x16, slightly smaller than yours.

[JasonP]

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

Maybe we should be monitoring your thread! That should be a cool project though.

Thanks! Yours too. No thread yet on the 1500, not until I make sawdust!

[lorenmjones]

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

Well at this point I think we are starting to get close to nailing some things down.

Box -- something like 15 x 42" baffle with depth as needed for desired volume. Target 100L give or take for volume.

Moderate sensitivity, moderate LF extension, relatively high output capability, 8 ohm friendly.

Drivers -- certainly still some room for discussion but these three seem like solid choices that will get us where we want to go. I'm pretty certain we have hashed out the woofer discussion quite a bit but feel free to mention others. Open question regarding the mid is with a 92db woofer and the planned baffle and crossover (around 300) how much sensitivity do we need the mid to have? This may open up more choices for a mid. There are several tweeters that could work, but the DX25 is pretty well respected and has all the sensitivity and output we could want for this.

http://www.parts-express.com/vifa-dx...eter--264-1020

http://www.parts-express.com/faitalp...-ohm--294-1151

http://www.parts-express.com/dayton-...oofer--295-120

[JasonP]

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

Since you are doing BDS shots earlier, this is why I chose a sealed box for the DA270 (besides that it is like the target I am emulating :D). Here is the BDS simulation of my box placed as an active filter in Unibox:



Ignore the SPL and excursion charts, adding an active filter messes with all of those. You can see though that the response has a lot of depth in room. Power handling is likely not up to your target though.

[lorenmjones]

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

That certainly extends plenty deep enough if that sim is accurate. Pretty impressive for a sealed 10"...

Since you are doing BDS shots earlier, this is why I chose a sealed box for the DA270 (besides that it is like the target I am emulating :D). Here is the BDS simulation of my box placed as an active filter in Unibox:

[ATTACH=CONFIG]48189[/ATTACH]

Ignore the SPL and excursion charts, adding an active filter messes with all of those. You can see though that the response has a lot of depth in room. Power handling is likely not up to your target though.

[joeybutts]

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

Just want to be clear Loren, since I saw you posted the 6fe200, I have the 8fe200.

[JasonP]

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

That certainly extends plenty deep enough if that sim is accurate. Pretty impressive for a sealed 10"...

It does include room pressurization, so its likely hopelessly optimistic under 30 hz in my experience, but it does give you an idea of needed baffle step. For my design its looking like 2 db or so.

[djg]

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

You linked the tweeter twice.

[lorenmjones]

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

I fixed it now...oops.

You linked the tweeter twice.

[lorenmjones]

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

I fixed it now...oops.

You linked the tweeter twice.