xt25 in 12in waveguide experiment

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#22
update. one speaker is finished.
 

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#24
MisterTwister said:
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Click to expand...

The baffle looks good,

question please:

1. what is your x over freq. for the XT25 and woofer?

2. The 12in horn you are using is similar to parts
express, that model states the min x-over 1khz.
is the horn the same as that used in parts express?

3. If you use a more efficient woofer the overall
speaker would be very effcient. You did mention
what woofer you are using.

keep us posted.
 
#27
MisterTwister said:

what I did not expect is that woofer will give me more trouble than tweeter. frequency response is a roller coaster with thin picks and dips, and there is no bass, although it can be equalized.
🙂 ).
Click to expand...

thanks for update.

I have built a open baffle using std 12in woofer with qts=0.55 and I don't get any bass, my baffle width is not very wide. I notice your baffle is not wide either. I really need a woofer with Qts greater than 0.7 so that I can get a decent bass.

I then build a U frame and bass improves now I am having resonance which can be solved. I don't suggest you build a u-frame, what you need is an equalizer at the bass end. That will solve your problem.

cheers, your Xt25 horn looks very interesting I may try it someday. I don't suggest you x-over below 1khz. I prefer 1.5kz and above myself.

Just a note, if you look at Emerald Physics(EP)'s speakers, open baffle, horn tweeter with DUAL woofers, it sounds very good according to most listeners. I think you should think about putting dual woofer(will improve bass) and existing tweeter, your combination with some tweaking will sound very good. The total cost will still be very low. You can use cheap woofers from Eminence, they will sound very good, alpha, beta or delta range.
refer to this web page, CS2 product from EP,

http://emeraldphysics.com/intro.htm. The price per pair is US$3000 retail.

BTW the speakers uses DCX2496 as DSP, you don't have to use it. You can duplicate the features using discrete components, eg equalization(bass end) and x-over between tweeter and woofer. more work for you!

keep us posted. hope the above info will keep you motivated.
 
#28
MisterTwister said:
I think I'll use this crossover for tweeter. see attached
it's obvious that tweeters distortion will be dramatically reduced.
Once I put speakers in listening room, I'll equalize woofer.

Later I plan to try full range driver and ribbon tweeter in waveguides.
Click to expand...


Question:

You said you get 10db boost when using horn, I think it maybe at around 500 to 2 khz, after you apply 2nd order filter looks there is no gain, could also be a loss in gain, please confirm.

I find certain type of full range is not sound as good in open baffle, I tried fostex FE167E on OB, it sounds ok but not that great. I heard Visitron, B200 is quite good but more expensive.

another alternative I am thinking is using, midrange Audax P170, SPL =100dB, from Madisound. At least 2 persons from this forum got very good result. The config. is 1 Audax with 1 or 2 woofers and 1 compression driver.

I also heard from a no. of sources that cheap to moderate price ribbon is not that dynamic only very expensive one like Raal, try compression driver, brand=BMS, B&C , Radian with horn. Many have tried this arrangement and get very good result.

This is what I found reading from a no. of postings on this forum. I think they comments are quite accurate. The decision is yours.
 
#29
MisterTwister said:

we usually apply baffle step correction to full range drivers to make frequency response flat. but what if we instead boost lower frequencies by using waveguide, it doesn't add any distortion and we maintain high efficiency and supposedly should have better off axis response. I understand that waveguide/baffle must be pretty big, but not necessarily ugly 🙂 so for this project I'm interested only in fr drivers that have rising frequency response, such as fostex, or ribbons such as
Neo 8
Click to expand...

no sure what you mean, OB no need for baffle step compensation I think. anyway if you don't want to explain it is OK.

I still think you use your existing horn tweeter and dual woofers per side, this configuration will sound great. 1 woofer is not suffcient. Make baffle wider, then equalise bottom end, X-over at 1-1.5khz.

After that you can proceed to next project.

That is my opinion, ignore it if you like that's ok too. That is all I can contribute.

cheers..
 
#31
I don't know which position is better. looks like C point can't be ised, it's part of tweeter's membrane. I am using point A and thin electrical tape going from B to waveguide (going over point A)
If I did it again, I would remove faceplate from tweeter and fit waveguide tightly to point B.

p.s.
ignore my last two measurements. something strange has happened, I can't replicate them. I'm getting usual 10db boost.
:cannotbe:
 
#32
My membrane is glued to faceplate :dead: Interestingly flattening the spectrum via DSP removes honking considerably. I would say the horn is extremely sensitive for a shape of transfer function. The step from unpleasant sound to acceptable is very short. Few weeks ago I was examining bending wave transducer made of 15cm cone rear suspension. It had many high-Q peaks and never the sound was unpleasant for me. Completely different stuff.

All the delayed energy (higher order modes) seems to be visible on CSD plot easier.
 
#35
top graph is modeled crossover,
lower graph is measured response 4ft away from speaker on tweeter axis. tweeters are powered by t-amps and woofers by amp6's.
level is matched by amplifiers gain controls. lower frequencies will be filled by dipole subwoofer (two 15 in woofers)
These speakers are loud, even with t-amps(main volume controlled by tube preamp)
I still need to do more tweaking.
 

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