Open Source "Tower XL"

Status
This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.
The crossover frequency is 650 Hz in this system and the acoustic center offset becomes less critical for a lower crossover frequency. But still there wiil be phase misalignment in this system.
Technically, I am not in favor of such a design. Maybe the frequency response can be designed flat, but there is a timing problem, because high frequencies are always coming too late.

Hey Paul, you are right I did not paid attention that Calpamos crossed that low, I understand what you mean about time alignment, I had some experience with dsp and different delays and scopes and have to say I like a transient perfect crossover with right time alignment, it sounds different.

that is a rather difficult compromise, I would say lets keep the time alignment the priority.

I took a look at the shallow BMS and beyma horn you sent, couldn't find any reviews on the beyma one and the BMS one is hard to find.
 
Hi Everyone. I figured I should probably update here to keep communication open....

Hi John,
I appreciate that you taking time to reply to the forum, I received the drivers today and man they are heavy :D and very good looking !
We will finish this project and it is good to hear we have your support if anybody interested to try this :)

attachment.php


the GF is visiting her family so looking forward to start some measuring this weekend :D
 

Attachments

  • _DSC7118.jpg
    _DSC7118.jpg
    214.2 KB · Views: 457
Grats Aatto, they look nice.

Just posting again once it's similar with what we are searching and has a good bang for the bucks costs.

The link below are related to a PDF file from a project that integrates 8" midrange Eminence Beta-8A with the 1" CD Selenium D220 + Selenium Horn HM17-25 (78mm deept). There are many details inside including crossover and directivity.

https://www.google.com.br/url?sa=t&rct=j&q=&esrc=s&source=web&cd=13&cad=rja&uact=8&ved=2ahUKEwiXyYWzra_eAhUIC5AKHe-iAhEQFjAMegQIARAC&url=http%3A%2F%2Fwww.audioheritage.org%2Fvbulletin%2Fattachment.php%3Fattachmentid%3D77902%26d%3D1503091842&usg=AOvVaw3ellDqodQGNxKAqzAtvqza
 
Considering midrange and tweeter being crossed at 2000Hz witch wave length is 0,17m (170mm) why a relative difference like 30~40mm between related drivers would be bad as time alignment?

As said by Jonasz, higher order crossover would also help, probably a 2nd order (12dB/oct) would be enough to fix any issue related to time alignment in the example above at crossover range.

4000Hz wavelength = 0,085m (85mm)
8500Hz wavelength = 0,040m (40mm)
 
Last edited:

The directivity index DI of the Selenium HM11-25 is 11 dB, that is too high to combine with the 8 inch midrange.
The Selenium HM 17-25 DI is 9 dB, that is already better, but it is deeper.

The preferred DI is 7-8 dB at 2kHz and 9-10 dB at 10kHz.
And a horn depth of about 40 mm should be ideal, but I think they don’t exist.

Look to my post #519 https://www.diyaudio.com/forums/multi-way/327657-source-tower-xl-52.html#post5592545 with the DI of the AE TD8M and some other tweeters.
 

Faital Pro STH100 has DI somewhere around 6db at 2kHz and fepth seems to be ~86mm.
FaitalPRO | HF Horns | STH100 (click Response Curves tab on the page)

LORDSANSUI link above says STH100 goes rather well with a 8" driver (Dayton RS180S though).

Also, it would be possible to recess the 8" driver in to the baffle to align with a tweeter in a waveguide?


Mr. Patrick Bateman has some knowledge on special waveguides :) Ultra Shallow Waveguides
 
Last edited:
Also, it would be possible to recess the 8" driver in to the baffle to align with a tweeter in a waveguide?

I was thinking about this yesterday. From a construction perspective, it's certainly not too difficult, especially if one makes their baffle from multiple layers of material.

Two layers of ~18mm MDF/BB could help bring a shallower waveguide like the SEOS' very close to the 8" mid-woofers.

If there is enough consensus to try this, I will make an additional baffle with this offset for the prototype cabinets I'm going to make for Aatto. We can then measure and listen to a version with the mid-woof recessed back a bit.

Cheers,
Gable
 
Diffraction could be a bit of an issue for sure, and it would add some complexity in constructing the baffle.

I think Paul is probably right, it may create too many additional issues to be worthwhile.


I can't recall, is there a plan to have the TD15 moved forward on the baffle to aid in time alignment of LF and MF drivers? It is easier to pull off while retaining good aesthetics and diffraction mitigation, in my opinion.
 
Last edited:
OK interesting topic,
Since this can take long and we will loose interest, lets compare the choices, this may help to come to a conclusion.

with CD+Horn we have the davantages of horn but we will have problem with acoustic centers and time alignement, we might be able to pull this off by a higher order crossover but at the same time it can complicate the design. Unless we can find a shallow horn.

second option with be Dome+WG, we will not have AC issue with this option, but the available driver choices are limited compare to a CD.

I think we can agree that we do not make a huge compermise in anyway if we go with either options. we did have simplicity in mind through out the whoel project and if one option is making more sense to help keep things as simple as possible then lets go with that, I m abit confused with going back and forth between the options but this is because both options are good and makes sense and this is the nature of group designs I guess so I m sorry if I m not helping.

I would appreciate it if someone more knowledgable can add more to this and make the choice easier.
 
Faital Pro STH100 has DI somewhere around 6db at 2kHz and fepth seems to be ~86mm.
FaitalPRO | HF Horns | STH100 (click Response Curves tab on the page)

LORDSANSUI link above says STH100 goes rather well with a 8" driver (Dayton RS180S though).

Also, it would be possible to recess the 8" driver in to the baffle to align with a tweeter in a waveguide?


Mr. Patrick Bateman has some knowledge on special waveguides :) Ultra Shallow Waveguides

Came across this horn, I like it because it is aluminum, but also came across this from PE comments :

"This Tractrix horn does what a tractrix horn is supposed to do: fairly even off axis response: horizontally and vertically; and no noticeable horn honk; high quality cast aluminum construction... all the good stuff. Now comes the price of admission: get ready to compensate for the huge peak around 4 kHz. I had to apply a -12 dB bell notch filter, q = 2, to make the response flat. This is with a crossover point of 1.8 kHz. Obviously it is not something easily done with passive crossover; but in a bi-amped setup with DSP, you have a pleasant sounding horn that has a pretty even off-axis response."
 
For an 8" midwoofer, the $28 SEOS-10 waveguide with the $63 Peerless 1.75" DFM-2544R00-08 compression driver would get positive votes.

Parts Express sells a $15 copy of the SEOS12 with screw-in, and the $35 Selenium D220Ti-OMF-8 1" compression driver screw-in would be the lowest cost good CD option. The EconoWave work has proven crossover ckts.

I believe the Seos 12 copy is no longer available... At least last I checked :(
 
I think I will take the liberty of narrowing down the choices to two options since I m building this.

Satori TW29RN-B-8 + WG148.
I like this tweeter, seems like a good fit, not sure if it has been brought up before, the only thing is that I m not sure how would it fit WG148 since it has a weird concave shaped face.
with this option the acoustic center would still be a about 20mm off in front of mid driver.

FaitalPro HF109 + Seos10
With this we will have the acoustic center about 40mm behind the mid acoustic center.

none of the options will have the ACs aligned.

what do you guys think of this tweeter +WG ? I might got the calculation wrong if the dome gives us a better alignment I will go ahead and order them.

Happy Thanksgiving :)
 
Last edited:
Status
This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.