Designing my first 2-way speaker

[Twisted85]

Hi,

I'm designing my first own speaker and I thought it would be wise to start with a simple 2-way speaker. I'm not planning to make a great sounding high-end speaker, I just want to make my own working nice sounding first DIY speaker and learn as much as possible from it.

I've been going through different speaker models and I've been thinking to use these two drivers:

Peerless V-Line XT25TG30-04

Peerless HDS Exclusive 830883

Highpass for tweeter around 2500Hz, maybe just a bit lower. I'm thinking of making 12dB/oct crossovers for both HP and LP.

I've been also planning to make a waveguide for the tweeter, so it would be on the same depth as the woofer.
The XT series tweeter has a little groove around the actual speaker so the waveguide has to start a little further away from the center.

I made a picture about the waveguide setup to clear things up: (propotions do not apply)

http://personal.fimnet.fi/private/clan/peerless.jpg

I made two different pictures, because I was going to ask your opinion what shape the waveguide should be? More like the one above or the one below?

If the tweeter amplitude decreases as the frequensy rises, I will try parallel capasitor with the series resistor, so the resistor only applys to the lower frequencys (under 7KHz or something like that)

I haven't yet decided should I make ported or sealed baffle for the woofer. I'm still thinking this and any suggestions are welcome.

I will try using computer programs to estimate the crossover parts values and I have Behringer ECM8000 microphone, so I will measure the speaker outside so I will have some information about the frequency response.

What do you think about this project? Any possibilitys to succeed? Any suggestions or advices?

Thanks.

[sreten]

Hi,

You don't need near top-notch drivers to learn a lot of stuff.

http://www.zaphaudio.com/

for info on drivers / design methodologies (soundeasy)

http://www.rjbaudio.com/projects.html

for more on simulation methodologies ( FRD tools)

/sreten.

P.S. the tweeter surround is convex, not concave.

[Twisted85]

Originally posted by sreten
Hi,

You don't need near top-notch drivers to learn a lot of stuff.

The largest Audio DIY shop in Finland offers these drivers: Seas, ScanSpeak, Peerless (V-Line), Visaton, Morel, Fountek, Eighteen Sound. Specified to the first three, I might say.
Seas and Peerless makes high-quality drivers for reasonable price, and while I'm trying to make a decent speaker, might just use quality drivers

I've made few speakers by instructions before using Seas drivers, but I haven't designed my own speaker yet.

http://www.zaphaudio.com/

for info on drivers / design methodologies (soundeasy)

http://www.rjbaudio.com/projects.html

for more on simulation methodologies ( FRD tools)

/sreten.

I just introduced myself to FRD files few days back and I'm still learning how to use them properly. I've been reading those sites and got lots of useful information.

P.S. the tweeter surround is convex, not concave.

Are you sure? I was just today at my local DIY shop and took a look at the driver and I would definitely say it was concave.

[sreten]

Originally posted by Twisted85

Are you sure? I was just today at my local DIY shop and took
a look at the driver and I would definitely say it was concave.

Hi, would be the first tweeter I've ever seen with such an arrangement, /sreten.

[sreten]

Hi, I am talking about the physical front plate, not the diaphram, /sreten.

[Twisted85]

I added one more option to this picture:

http://personal.fimnet.fi/private/clan/peerless.jpg

I believe the front plate of the tweeter is removable by removing the three screws. This way I could fill the surrounding (without destroying the actual driver ) and make it a straight angle. And then I could put the waveguide like in the picture.
What do you think? Could this work or should I just put it like in the first picture?

I am interested to use this setup because in this article/test a ring radiator seemed to work best with a waveguide

http://www.aeronet.com.au/waveguide.htm

[Reilumeininki]

Terve!
You believe right.Front plate is removable.Picture and few words about it from finnish site:

XT without frontplate

Filling the surround could make actual responses worse if it straight so that actual membrane is like coaxial driver.Like little peaking on high frequencies.But if it curves smoothly like the the original plate it would not be a problem.Do you know about Monacor waveguide?
waveguide
Monacor throat could fit without any discontinues to your XT's.

[ralphs99]

Hi Ari,

I agree with Reilumeininki that the Monacor waveguide could be a good place to start. It's inexpensive and might be a good fit to the XT-25. I plan on trying it out for myself in the near future.

Unfortunately the XT-25 is difficult to mount with the front flange removed. For my experiments I was forced into temporarily fixing the driver to the waveguide with removable adhesive. It wasn't ideal, but was good enough for my measurements.

I am a bit concerned by your initial drawings that the contour doesn't look suitable. The most sucessful designs all seem to feature a largely conical section with a generously rounded flange where the waveguide terminates to the baffle.

Cheers, Ralph

[Twisted85]

Thank you for your reply.

http://www.monacor.de/de/JPG/400/G/G1/G110110Z.jpg

The Monacor waveguide seems to have 38mm hole, and I believe it could be pretty close to the desired one.

Unfortunately this picture of XT25 doesn't have the needed measurements.

http://www.tymphany.com/datasheet/dwg/XT25TG30-04.gif

I have to find out can I get that waveguide from Finnish importer.

[peace brainerd]

By "largely conical section" are you describing straight profiled as opposed to curved?