Speaker-Camp, R&D for Modula NeoD CC speaker variants

[Mark K]

...
I will have a test sample of the Seas DXT waveguide sent to me when production is ready. I've seen a preliminary response curve of it though, and the interesting thing is that it uses the 27TBFCG but it doesn't have the nasty top octave dips that I saw when I tried it in the MCM waveguide. I'm curious to find out why. It's probably the lack of the original grill design, phase shield or something. Bottom end behavior is similar to the MCM. (this may be another single cap filter)

Lucky dog...

[jkrutke]

I'll be quite curious to see what you think of the Seas DXT, and how it works overall. When you tried the 27TBFCG in a waveguide, did you remove the so called phase diffusor? I'd expect that to interact with a waveguide mouth in unusual ways.

...Can you share the dimensions of the DXT waveguide, and intended lower operating frequency?

When I tried the 27TBFCG in the waveguide, I left the grill on. I didn't want to mangle the tweeters since they were borrowed from another system. I won't really have much information about the DXT until I get one in my hand. So far all I know is the design and response curve shown in Voice Coil a while back, and a few details that Madisound mentioned to me. But, I think it's about 6" diameter, and I suspect 1300 or 1400 LR4 would be the lower limit depending on the listener's volume habits.

Lucky dog...

Not really. Most of the drivers people send me to test have to be sent back. So far this year I've spent $500 on return shipping. Not exactly cheap to satisfy my curiosity. Occasionally, I'm lucky enough that a vendor or two lets me keep the drivers. But on the other hand, if nobody offers up the drivers I want to test, I have to pay for them myself. That's often a massive money losing venture.

[JonMarsh]

But on the other hand, if nobody offers up the drivers I want to test, I have to pay for them myself. That's often a massive money losing venture.

No kidding! BTDT, own the movie rights and the iTunes distribution contract.

[JonP]

When I tried the 27TBFCG in the waveguide, I left the grill on. I didn't want to mangle the tweeters since they were borrowed from another system.

As I recall.. someone out there (Dave Ralph?) did dismantle the hexgrid cover off of a TBFC fairly safely. Think it was glued, so reverseability could be problematic...

But, we digress... :W

[TacoD]

But on the other hand, if nobody offers up the drivers I want to test, I have to pay for them myself. That's often a massive money losing venture.

I do not understand your reasoning. Everybody else also buys his own drivers .

[JonMarsh]

I do not understand your reasoning. Everybody else also buys his own drivers .

Except MarkK, who gets bazillions of guys to send him stuff to test. Smart guy... :B

[dlr]

Not the 27TBFC...

As I recall.. someone out there (Dave Ralph?) did dismantle the hexgrid cover off of a TBFC fairly safely. Think it was glued, so reverseability could be problematic...

But, we digress... :W

It was the 22TAF/G. It comes off fairly easily. I was able to re-position it without gluing it, but that does leave it in a precarious situation.

[Mark K]

Well,
I'm not really trying to get free drivers. I'm just kind of bored with the usual 6.5 in midwoofers... Not much is interesting-although the Seas reed looks nice for a nonmetal.

I wish someone would send me a waveguide/horn loaded 27TBFC/G...not that I want a free one. I just don't want to make one. Seas needs to hurry up and get these to market. I'm curious how much lower these can go with the same distortion as the nonloaded versions...

[Jed]

http://audiofest.net/2007/

Thanks Thomas,

I'm working on getting some tickets to come out to Denver for the weekend. Just waiting to hear back from my sister (she lives in Denver), if it'll fit in her schedule. Do you and Jon definitely have plans to show off your speakers there? If so I'll try to get to that room! Maybe you can bring some dipoles too.

Jed

[Jed]

Well,
I'm not really trying to get free drivers. I'm just kind of bored with the usual 6.5 in midwoofers... Not much is interesting-although the Seas reed looks nice for a nonmetal.

I wish someone would send me a waveguide/horn loaded 27TBFC/G...not that I want a free one. I just don't want to make one. Seas needs to hurry up and get these to market. I'm curious how much lower these can go with the same distortion as the nonloaded versions...

Agreed, I'd buy a pair of the waveguide tweeters as well. I'm also curious about how well the 8" nextel performs. The FR looks good and the Nextel woofers seem to get better in performance as the diameter of the cone increases. At least in terms of harmonic distortion.

[ThomasW]

Do you and Jon definitely have plans to show off your speakers there? If so I'll try to get to that room! Maybe you can bring some dipoles too.

The plan is to have an open house probably Sunday afternoon, that way people can just drop by. (Note, my house is literally 5 min away from the RMAF venue. We can provide transportation for those without rental cars)

In addition to the usual speakers we'll have the new compact WMTW and a fully operational prototype of the dual 12" woofer Isiris up and running.

If some can't make Sunday afternoon we'll make other arrangements for them

[Carl V]

Hello Thomas

I'll be there again...looking forward to the meet & greet.

cheers

carl

[ColoradoTom]

The plan is to have an open house probably Sunday afternoon, that way people can just drop by. (Note, my house is literally 5 min away from the RMAF venue. We can provide transportation for those without rental cars)

In addition to the usual speakers we'll have the new compact WMTW and a fully operational prototype of the dual 12" woofer Isiris up and running.

If some can't make Sunday afternoon we'll make other arrangements for them

Hey Thomas......

Are ther any specific times you want people to come by? Also, is there anything I could bring to help out if I can make it??

Tom

[JonMarsh]

Well,
I'm not really trying to get free drivers. I'm just kind of bored with the usual 6.5 in midwoofers...

Then you have to go test the UNUSUAL 6.5 in midwoofers.... or try a different size... :W

just pulling your leg a bit, Mark....

[JonMarsh]

Hey Thomas......

Are ther any specific times you want people to come by? Also, is there anything I could bring to help out if I can make it??

Tom

How are you feeling Tom? We hope you can come by but understand your family schedule may preclude....

I'm planning on playing comp time hooky and coming out early the week before- we've got a lot to get ready. Going to send out some of my gear and cables, too.

All in all I'm certainly looking forward to this. I've heard that exhibitor space has sold out.

This may deserve it's own thread/sticky leading up to the event.

[ThomasW]

Carl,

Looking forward to seeing you again... :T

Tom,

Jon's coming to Denver earlier in the week, maybe we can bop out and give your toys a listen...?

Let's discuss specifics via phone

[ColoradoTom]

How are you feeling Tom? We hope you can come by but understand your family schedule may preclude....

I'm planning on playing comp time hooky and coming out early the week before- we've got a lot to get ready. Going to send out some of my gear and cables, too.

All in all I'm certainly looking forward to this. I've heard that exhibitor space has sold out.

This may deserve it's own thread/sticky leading up to the event.

Doing great... I've been dealing with this for over a year and really hadn't realized how bad I'd been feeling. Had post surgery meeting with the doctor yesterday and he said I can be lifting > 60 lbs within a couple of weeks! :T Probably back to woodworking/speaker building in mid-October.

No problem with a visit to the house..... working on some acoustic stuff this week (because the materials are all light!!)

Tom

[ColoradoTom]

Tom,

Jon's coming to Denver earlier in the week, maybe we can bop out and give your toys a listen...?

Let's discuss specifics via phone

Can do.... will call/email in a couple of weeks.

Tom

[JonP]

Must have been someone else, I'm pretty sure it was a TBFC. I do remember you doing the 3/4" version now. They seemed to be the same in grill construction.

It would be interesting to see if the TBFC behaves nicer w/o the phase shield and grill in a waveguide. Maybe I'll get curious enough to carve up the MCM guides gathering dust around here, buy some TBFC's, make a custom grill
puller.... and Mr J and or Mr K might have a package show up in their mail.

I'm still thinking of the horn loaded RS225 two way I was starting to play around with last year... :roll:

[FrederikCaroe]

Sounds fine by me.... :T

The article about the thread suspension for a Scan Speak 21w is done. Where to put it?

[ThomasW]

The article about the thread suspension for a Scan Speak 21w is done. Where to put it?

Hi,

For discussion purposes start a thread in this section. Eventually we'll probably move it to permanent sticky status in Missions Accomplished.

[Dennis H]

Fun with MathCAD

Some may remember, way back in the middle of this thread, I posted a spreadsheet for the Duelund 3-way. I could never get the 4-way to work and after beating my head on the wall and listening to Jon telling me I was an idiot not to use MathCAD, I finally listened to Jon. I snagged the old copy of MathCAD 7 that Danish was giving away (thanks Danish!) and spent the last couple of evenings trying to learn to use it for something useful. First was a Duelund 3-way using hints Jon dropped in the 3-way Design Study thread. I was like a blind squirrel looking for an acorn but I finally got it to work. Then it was a simple matter to modify it for a 4-way. If there's any interest, I'll post the worksheets. They seem to run a lot faster than the ones written by Steen Duelund and posted by Frederik, probably because mine use the native S-plane equations and I made an effort to avoid repetitive calcs. They will also output the data to .txt files.

[Jed]

Dennis,

You're the man! :T I'd like a copy very much.

Jed

[Dennis H]

Okay, here are the 3-way and 4-way MathCAD worksheets. Change 'Fc' and 'a' or 'b' at the top to whatever you want and then scroll down to the graph. After you get it looking the way you like, do Math / Calculate Worksheet in the menus to output the .txt files to the same folder where the worksheet is. I couldn't figure out how to output more than one variable to a file so the frequencies are in a separate file. It's easy enough to copy/paste the numbers into Excel to get frequency and dB side by side. While you're at it you can format the number of decimals down to something reasonable.

[Dennis H]

I just replaced the file above with a new version. No big changes, just fixed a few typos like the title of the 4-way was still labeled 3-way.

[Paul W]

The 4-way sure looks like a natural for a W22 lower mid, RS-52 upper mid! Huge flexibility with woofer and tweeter selection.

[Dennis H]

The 4-way sure looks like a natural for a W22 lower mid, RS-52 upper mid! Huge flexibility with woofer and tweeter selection.

Yup, it gets you a real 20-20K speaker with a good blend all the way up! Most any good sub driver would work for the bass. The low mid could be a W22 or an RS225. The high mid could be an RS52 or a TB W4 depending on whether you were going monopole or dipole. You could do a Vifa D26 or a BG Neo3 for the tweeter depending on monopole or dipole. Adjusting Fc (center frequency) and b (which basically sets the bandwidth of the mid drivers) would let you optimize it for the particular drivers you choose.

The catch is all the components you'd need to do a passive version of the XO. Matching the transfer functions with an active XO, at least for the lower frequencies, might be more practical.