Double 10 and Horn

[Johnny Holguin]

I was looking at using a plate amp to build into the cab. I found some decent ones with built in DSP but most lack in functionality. Here's a screenshot of the software from one of these amps. Do you guys think this would be enough to setup the cab?

In the high pass/low pass xover section how would I set this up for the coaxial using the BMS crossover?

 

[Chris Burns]

Looking for a build sheet/cut sheet for this great design. I might have missed it?

 

[Chris Burns]

I was looking at using a plate amp to build into the cab. I found some decent ones with built in DSP but most lack in functionality. Here's a screenshot of the software from one of these amps. Do you guys think this would be enough to setup the cab?

In the high pass/low pass xover section how would I set this up for the coaxial using the BMS crossover?

Which Amp is that? Which have you looked at? Great idea!!!

 

[Max Warasila]

Quick question here - let's say you leave the enclosure as one giant cavity instead of using a divider and end up with a total internal volume of 65L or so - my calculations are saying that the ports could be left as literally just 60mm diameter holes in the plywood. Does that sound right to you, Peter? Does that create any particular issues with the cabinet?

Also, Chris and I are taking a look at the center horn arrangement.

 

[Peter Morris]

Quick question here - let's say you leave the enclosure as one giant cavity instead of using a divider and end up with a total internal volume of 65L or so - my calculations are saying that the ports could be left as literally just 60mm diameter holes in the plywood. Does that sound right to you, Peter? Does that create any particular issues with the cabinet?

Also, Chris and I are taking a look at the center horn arrangement.

Yes - that does sound about right. Be careful, many drivers will not like a box that big and you can easily end up with a resonant peak around the tuning frequency of the box.

The only issue with the MTM arrangement is ensuring the vertical directivity does not collapse too much around the crossover frequency.

 

[Max Warasila]

Yes - that does sound about right. Be careful, many drivers will not like a box that big and you can easily end up with a resonant peak around the tuning frequency of the box.

The only issue with the MTM arrangement is ensuring the vertical directivity does not collapse too much around the crossover frequency.

The Vas of the 10NW64 is 27.5L, so I think it works out pretty well considering.

The real trouble of the MTM arrangement is dealing with the ports. I think they will end up being quite tight in the center around the HF950, but four 45mm diameter ports seem to just do the trick. The really clever bit may end up being building flanges for the internal side of the horn to net a better end correction and shorten the ports.

 

[Chris Burns]

Quick question here - let's say you leave the enclosure as one giant cavity instead of using a divider and end up with a total internal volume of 65L or so - my calculations are saying that the ports could be left as literally just 60mm diameter holes in the plywood. Does that sound right to you, Peter? Does that create any particular issues with the cabinet?

Also, Chris and I are taking a look at the center horn arrangement.

Max and Peter thanks much.

 

[Chris Burns]

Out of curiosity, opinions on the XR1464 Horn by 18Sound? Comparison to the RCF950? Just curious as it's spec'd at 60x40 yielding ability to splay a pair of cabs per side. Thoughts?

Also Peter what happens if you drop your xover on the double 10 MMT to 450hz? Does it fall apart?

 

[Chris Burns]

The Vas of the 10NW64 is 27.5L, so I think it works out pretty well considering.

The real trouble of the MTM arrangement is dealing with the ports. I think they will end up being quite tight in the center around the HF950, but four 45mm diameter ports seem to just do the trick. The really clever bit may end up being building flanges for the internal side of the horn to net a better end correction and shorten the ports.

Okay one more question...

What if.......

The 10NW64 is replaced by the 12NW76

Double the power handling (therefore plus 3db net gain each driver), similar properties, similar sensitivity and curve.... would this bring up the midbass to match the SPL of the 4594 and lower that 10DB difference to the Mid Hi?

Sorry for all the questions guys. I do however appreciate the help.

 

[Bennett Prescott]

The 10NW64 is replaced by the 12NW76

Double the power handling (therefore plus 3db net gain each driver), similar properties, similar sensitivity and curve.... would this bring up the midbass to match the SPL of the 4594 and lower that 10DB difference to the Mid Hi?

Hey Chris, I would consider our 12NDL88 in that case. The 3.5" coil will gain you a little power handling, sure, but more importantly it has significantly better LF than the 12NDL76. If you're going to a 2x12" large three way box anyway, it should be pretty full range IMHO.

 

[Peter van Gils]

When going to 12", then why not build Peter's hornloaded 2x12" design?


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[Max Warasila]

When going to 12", then why not build Peter's hornloaded 2x12" design?


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Chris was considering that, but a MTM dipole arrangement of this design was chosen for price considerations and build simplicity. I personally think it should stay a 10" design because I'm rapidly running out of front baffle space for port area as it is!

I was going to recommend exactly what Bennett did if Chris really wanted the 12", though.

 

[Johnny Holguin]

I have a similar issue with the ports. I thought, well, why not put them in the back?

@Max -- Would you mind exposing what speaker software your using? I'm using a cheapie and unsure about what it's telling me. It's recommending that the enclosure volume for the 10NMB420's should be 15L.

Got drivers in! And they look so nice on my wife's table.

 

[Chris Burns]

How about small slotted ports on either end of the MTM? May need to make the cab a bit taller but seems best option for efficient use of space. You can even do one at one end, just makes that then the "bottom" end of the cab if running the cabs entire enclosure as the chamber. Just a thought.

 

[Chris Burns]

Hey Chris, I would consider our 12NDL88 in that case. The 3.5" coil will gain you a little power handling, sure, but more importantly it has significantly better LF than the 12NDL76. If you're going to a 2x12" large three way box anyway, it should be pretty full range IMHO.

Thanks Bennett. Is the NDL a better choice than the NW series for these purposes? Probably just looking to maximize output to about 70-80hz for my uses. Getting crossed over to a sub array.

Personally size wise I wouldn't mind taking this from a double 10 to a double 12. Peters MidHi is an great design, but for me, cost and build complexity far exceeds my capabilities hence wanting to maximize the basic surface mounted vented concept.

Also, wanted to ask are you still in WallyWorld? If so we're neighbors. Feel free to PM.

 

[Max Warasila]

Chris,

Of course you want to make it a 12 - I just sorted out how to make the 10" work! :lol:

I try to avoid slot ports if at all possible. They just get worse airflow than other geometries, period. Add in the complications of the trap box and it turns out that it doesn't net as much as I'd want anyway. I was considering some more creative port geometries, but you wanted to keep the construction simple, so I just stuck with PVC pipe ports or very simple round ports as shown in this the attached drawings (anyone feel free to use these to go off of for a MTM version of this cabinet and ask me questions regarding it).

I'd like to actually get a good description of the different series that B&C has (as far as the model IDs go, such as NW, NDL, etc.) As I understand it, though, the NDL series uses an internal Nd slug and balances performance with weight, while the NW series uses a Nd ring and is more intended for bass performance in smaller cabinets - and by "as I understand it" I literally mean I basically took that right from the B&C website. Really what drives driver choice is the actual parameters and performance of the drivers themselves, not what series they are from.

Bennett - is there a good way to explain the model numbering system at B&C? PM or email me if you'd prefer.

John,

I personally use WinISD to get a general idea where to start. It's important (and has been stressed to me by several people), that the models that WinISD shows are only applicable to smaller signals and are not directly representative of actual performance. It simply does a lot of the math to develop a general alignment as you desire instead of having to do it by hand. I would expect that the cabinet suggestion you got was simply for a standard Qt of .707, but that is more certainly not the ideal alignment for this application.

The important thing to remember is that the calculators are tools to inform your design, not the final result. You will have to prototype your cabinets to confirm that it will work as expected and to finalize designs.

 

[Chris Burns]

Re: Double 10 and Horn



Hi Boyd,

The double 12 actually came about because everyone loved the double 10, but they wanted more power. Often they were requesting 2 boxes a side ... which was is not the best solution.

... So I set out to build another box with 6 dB more output. With the DIY double 12 I think I ended up with more like 10dB.

Anyway I did think of putting another two 10 inch speakers on top of the double 10 like you are suggesting, but ultimately I thought the double 12 was a better solution.

When I have a moment I should try your suggestion. FWIW I have actually flown them two deep it seemed to work OK.

Hmmm, two more tens you say.....

 

[Johnny Holguin]

Actually, I don't think I was way off. I went back to Peters first post and he states he's using 40L for both drivers. Is it safe to assume 1 driver would get 20L? I'm building an MTM as well but I'm going to add a plate amp so I'm enclosing each of the 10's in its own space by adding some wood above and below the horn. Anyway here's a screenshot of my WinISD which I also use.

 

[Max Warasila]

Actually, I don't think I was way off. I went back to Peters first post and he states he's using 40L for both drivers. Is it safe to assume 1 driver would get 20L? I'm building an MTM as well but I'm going to add a plate amp so I'm enclosing each of the 10's in its own space by adding some wood above and below the horn. Anyway here's a screenshot of my WinISD which I also use.
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15L? Too little. 20L? Totally workable.

I did a little fiddling of my own. I think what really determines the end result of this cabinet's LF section is how low you want it to play. The 18 sound drivers are more sensitive in the midrange, but the B&Cs go lower. If it's used with a sub, why not tune the 18 sound 10s to about 79Hz and enjoy the added sensitivity like in the white trace attached? Might be what I do for the 4x10" + HF950 attempt.

 

[Bennett Prescott]

Thanks Bennett. Is the NDL a better choice than the NW series for these purposes? Probably just looking to maximize output to about 70-80hz for my uses. Getting crossed over to a sub array.

Hey Chris,

Better? Nah. Different? Yeah. The NDL series, especially the new 88mm motors, was more or less designed for two way line arrays. Enough HF extension to meet up with a compression driver, enough LF extension to sound good on its own, with weight as a serious consideration. If you really only need to hit 70Hz then the NW could be the better choice for its better sensitivity, but it's hard to say with a ported box. I would think two 12" would be a good match for a single mid/high compression driver, even at the sensitivity of 12NDL88. There may also be some advantage to running out of woofer first, it's usually easier to tell.

P.S. Living in Wallingford full time now, well - when I am home at least, so not this week! Anyway, would love to meet up, drop me an email - [email protected]