[Evoke]

Hey all DIY people.


I'm thinking of doing a contest and want your feedback. The basic idea is to give the DIY'ers an opportunity to win 2 or 3 mid-planar panels. (That's up to your design - left and right or an LCR concept... If a surround design, I'll even throw in some small planars for those.)


The best design would get them for free (not including shipping). (The retail value, if sold separately would be around $695 for each panel!)


Why am I doing this? I have no idea. Just sounds like fun to me.



If you think this is a good idea. Post here and then I can work up the details and rules.


 

[Peter J]

Free is never bad, right? 

On second thought, I can think of a few exceptions.

Here's where I can be in the overall scheme of the deal. Not a acoustics designer so much as a really capable fabricator. So if there's my polar opposite out there who digs the electrical and acoustic, but fab skills less of a thing, perhaps we can team up where the sum is more than the individual parts.

[Folsom]

Sorry, design of what? A speaker that uses them? That would be fun to me, but I don't know about someone else... in particular if I came up with the idea, you made it.

[mresseguie]

Mark,

What’s the sensitivity of the combo planars?

How low can the midrange planar be comfortably set with a crossover?

Thanks,

Michael

[Evoke]

Sorry, design of what? A speaker that uses them? That would be fun to me, but I don't know about someone else... in particular if I came up with the idea, you made it.

Yes, a speaker design centered on the use of these drivers. This is primarily for the DIY person that will build them out.

[Evoke]

Mark,

What’s the sensitivity of the combo planars?

How low can the midrange planar be comfortably set with a crossover?

Thanks,

Michael

Hey, Michael -


The tweeter is 92db efficient. 1.8 - 35k range.


The midrange is 97 db efficient. Top end is 22k. As for the low limit that's tough. The engineer yells at me all the time about that. If you use the driver "as is", 'he' would suggest 700hz with a steep crossover slope.


There are other options around that which require a pretty smart person who understands that any variance affects output etc... I can go into that separately. In any case, using a mid-bass driver of 10g MMS is absolutely seamless.


Let me know if you need anything else on that.


M

[mresseguie]

Hey, Michael -


The tweeter is 92db efficient. 1.8 - 35k range.


The midrange is 97 db efficient. Top end is 22k. As for the low limit that's tough. The engineer yells at me all the time about that. If you use the driver "as is", 'he' would suggest 700hz with a steep crossover slope.


There are other options around that which require a pretty smart person who understands that any variance affects output etc... I can go into that separately. In any case, using a mid-bass driver of 10g MMS is absolutely seamless.


Let me know if you need anything else on that.


M

Mark,

Is that 10g MMS exactly, up to 10g, or 10g or higher?

Thank you.

Michael

[Evoke]

Mark,

Is that 10g MMS exactly, up to 10g, or 10g or higher?

Thank you.

Michael

Anything under 10g. There are a lot of 6" drivers that are well under 10g. Using a pair of dual 5" drivers can really perform. The 5" drivers assume them as a mid-bass driver.  For example, Eddie has a 7". It's not under 10g but has bass extension below 30 hz. So you have a lot of options from a design point of view.

[Folsom]

I would need exact specs.

[Evoke]

I would need exact specs.

Midrange

8 ohm
97 db +/- 3db
60 watt power handling
120 watt peak
700 - 22Khz*

Crossover
   The engineer suggests no lower than 1000 hz, 2nd order*
   For the purpose of this design, 700 should be the lowest, 3rd order or steeper*
   (No design will be accepted that does not follow this minimally)
   (Designs must be phase coherant)
   I feel the sweet spot for this driver is up to 5000 hz max.

Tweeter

8 ohm
93 db +/- 3db
1.2 Khz - 35Khz
15 watt power handling
30 watt peak

Crossover
   The engineer suggests no lower than 1.6 Khz, 2nd order
   (No design will be accepted that does not follow this minimally)
   (Designs must be phase coherant)


*The driver is capable of more i.e. Adding a horn, chamber tuning etc. This is very advanced modeling and not supported in this program. In my products the crossovers are extremely well designed and the crossover points are inaudible. The MMS of the mid and/or mid bass driver is critical for this result to be achieved.

[hoxuanduc]

Will you need to approve the mid-bass drivers?  There are a lot of 5 in woofers less than 10g MMs.  One example below. Are you OK with MTM format?  Are we to purchase our own woofers for the design? Thanks, Duc

https://www.madisoundspeakerstore.com/approx-5-woofers/satori-mw13p-8-5-egyptian-papyrus-cone-woofer-8-ohm/

[Evoke]

Will you need to approve the mid-bass drivers?  There are a lot of 5 in woofers less than 10g MMs.  One example below. Are you OK with MTM format?  Are we to purchase our own woofers for the design? Thanks, Duc

https://www.madisoundspeakerstore.com/approx-5-woofers/satori-mw13p-8-5-egyptian-papyrus-cone-woofer-8-ohm/

I think part of your design is the choice of a mid-bass or other drivers. Of course, $3 for a cheap mid-woof might raise my eyebrows! LOL ...  That said, there are a lot of contenders such as AT, Eton, Satori, Seas, etc.


I think it's true for a lot of DIY people that you have already heard a finished design in your head before you even build it. That's what I do. When you consider your design, imagine how you feel the drivers will transition together. I don't think there's a right or wrong answer. I built several crossovers for the first Eddie with different slopes and different capacitors. They sounded everything from blurred to focussed and from lush to analytical. This is part of your magic.  Have fun!


M

[Folsom]

So no phase data or T/S ?

[Evoke]

So no phase data or T/S ?

It's atypical to see T/S data on planar devices (reference B&G Neo10 as an example.) If you feel that's something you want to measure to refine your design, you can certainly measure the devices as you wish, if your design is the one that is the most interesting.


The back chamber for the mid-bass planar is critically damped for extremely flat and accurate response, as is the tweeter.


Beyond that, the crossovers and topology I use in my products are proprietary.

[Folsom]

It's slightly hard to model without... Anyways.

What I'm thinking.

Tweeter crossed over at 8khz. 4rth order. It'll need some series resistance with it. How much I'm not sure, but I want to do like with the midtweet and try to push it towards current driven response a bit. 2ohm maybe?

Midrange/midtweet 3rd order on both ends. Crossed at 8khz and probably about 1.2khz (?). The reason for this is I'd want to vent to the outside with tiny holes that could be drilled to make it aperiodic, and I know the low end is going to trail off so it needs to be high enough to prevent that (I'd go lower if it could, to 1khz). It'll provide some extra damping. This is good because I want to put a fair bit of resistance in series with it. This will have to be tuned by ear most likely. But the intention is to move it into being more current driven, and let more of the physical properties steer it.

For a midbass I'd use the Zaph ZA14W08, 2x per speakers. I'd use them in bipole. Because I'd have them ported and running aperiodic in parallel (crazy I know, the port gain isn't terribly important). I'd expect it to run maybe into the 40hz range with a sensitivity around 87db (it'll need some BSC like crossover work because the gain from the room will be too much).  The ape vent can be on the top, and the port out the back above the woofer. The box would have a little bit of an L shape in a way because the tweet/midtweet would be mounted on the front without being inside the box, to let the mid run aperiodic.

I could be totally wrong about the whole thing but... just an idea. I think it might be fun on a tube amp. It'd sound serious gusto, and hopefully pretty articulate without a bunch of feedback.

[Folsom]

I might consider a different woofer that has a lower FS, if the QTS isn't too high. (and MMS isn't too much)

[Evoke]

It's slightly hard to model without... Anyways.

What I'm thinking.

Tweeter crossed over at 8khz. 4rth order. It'll need some series resistance with it. How much I'm not sure, but I want to do like with the midtweet and try to push it towards current driven response a bit. 2ohm maybe?

Midrange/midtweet 3rd order on both ends. Crossed at 8khz and probably about 1.2khz (?). The reason for this is I'd want to vent to the outside with tiny holes that could be drilled to make it aperiodic, and I know the low end is going to trail off so it needs to be high enough to prevent that (I'd go lower if it could, to 1khz). It'll provide some extra damping. This is good because I want to put a fair bit of resistance in series with it. This will have to be tuned by ear most likely. But the intention is to move it into being more current driven, and let more of the physical properties steer it.

For a midbass I'd use the Zaph ZA14W08, 2x per speakers. I'd use them in bipole. Because I'd have them ported and running aperiodic in parallel (crazy I know, the port gain isn't terribly important). I'd expect it to run maybe into the 40hz range with a sensitivity around 87db (it'll need some BSC like crossover work because the gain from the room will be too much).  The ape vent can be on the top, and the port out the back above the woofer. The box would have a little bit of an L shape in a way because the tweet/midtweet would be mounted on the front without being inside the box, to let the mid run aperiodic.

I could be totally wrong about the whole thing but... just an idea. I think it might be fun on a tube amp. It'd sound serious gusto, and hopefully pretty articulate without a bunch of feedback.

I would suggest using the same order crossover throughout the design to avoid phase issues. The midrange has very good dispersion to 5K. When I used a transformered ribbon tweeter I crossed it higher, but with a planar tweeter you have more flexibility to go lower.  I also find the optimal sound quality under 7500. Over that, I'm not fond of how it sounds, personally - although a bunch of them in a room all over the ceiling for surround up to 22K do sound fun LOL


There are a lot of good woofers in the 5" - 7" range. I have found 6" to be the biggest while keeping the MMS low. Keep in mind that this mid can match to a pair of 10" drivers in a pro-monitor application. That said, the "aural weight" can be a concern. Dual 5's will sound really great - but if you do want to move air, it's pretty common to cross to a good woofer, not sub, in the area of about 120 - but that's a personal choice. My Ruby's are a 2-way planar with a 5" and they kick butt. People wonder if there's a sub in the room.


Aluminum and magnesium or other exotic woofers are great. What you want to make sure is you don't cross too high so you don't introduce ringing from the cone. A great example of a well-damped speaker is the SEAS Excel W15CH001. Really a good driver - but $$$.


There are also some great offerings from ETON if you want to take out a second mortgage.  That said - you can carefully select a good-priced mid-woof if you do your homework. When it comes to caps in the crossover - well, argh... My speakers use about $500  in caps per speaker my OEM cost. I keep them in a safe


Sounds like you're having some fun. You combo would sound insanely good with a tube amp. With a good listening position it should compete with headphones. Given the value of the mid-tweets - be careful on your mid-woof selection. While price isn't everything - make sure it specs correctly. I have a closet full of woofers I thought would work and they were garbage. It's like cooking - a lot of tasting before you are willing to serve it at a dinner party

[Folsom]

I’ll take your word on the 7.5k! Probably worth bumping to 7k due to the crossover type.

I want the midtweeter to meld well with a pattern that isnt like LR4, so I would remain 3rd order (see YG speakers) The thing is at these frequencies it’s mostly irrelevant because they are shirt it’s imperceptible. Phase is a moving target. Up in this range you’re going to just be trading a set of frequencies in phase for another set that were out of phase previously. Besides it won’t be anymore off than a single cap speaker is, 90*. The only thing particularly key is that the overall phase doesn’t reverse and tends increase. The big concern is comb filtering. I’d use an elliptical/notch on the tweeter/woofer first attempt to reduce some comb.

I’m not  opposed to other woofers but the Zaph might be one of the few to keep up with the mid-tweet. It also has the right QTS you can’t find in pro drivers usually. By shelving off response it’ll play pretty darn deep! Bipolar tends to sound very robust in the bass. But I admit I’m thinking bookshelf. Otherwise probably add a bass driver in bipolar setup, and reduce the Zaph to one and no port just ape. But a bipolar TL might be a good small floor stander.

[Evoke]

I’ll take your word on the 7.5k! Probably worth bumping to 7k due to the crossover type.

I want the midtweeter to meld well with a pattern that isnt like LR4, so I would remain 3rd order (see YG speakers) The thing is at these frequencies it’s mostly irrelevant because they are shirt it’s imperceptible. Phase is a moving target. Up in this range you’re going to just be trading a set of frequencies in phase for another set that were out of phase previously. Besides it won’t be anymore off than a single cap speaker is, 90*. The only thing particularly key is that the overall phase doesn’t reverse and tends increase. The big concern is comb filtering. I’d use an elliptical/notch on the tweeter/woofer first attempt to reduce some comb.

I’m not  opposed to other woofers but the Zaph might be one of the few to keep up with the mid-tweet. It also has the right QTS you can’t find in pro drivers usually. By shelving off response it’ll play pretty darn deep! Bipolar tends to sound very robust in the bass. But I admit I’m thinking bookshelf. Otherwise probably add a bass driver in bipolar setup, and reduce the Zaph to one and no port just ape. But a bipolar TL might be a good small floor stander.

There are a number of tools in your arsenal. Keep in mind your love of music, your understanding of design theory. But most of all, trust your minds' eye. True magic comes from doing your homework, yet letting intuition guide you as well. Magic isn't born on a computer screen