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askevad

  • Newbie
  • Posts: 2
Hi
« on: 8 Apr 2022, 09:33 am »
Hi OB people!

I am from Estonia and new to this circle. I came here to ask for an advice.
It all began with casual visit to local Hi-fi guy with OB setup (cheap soviet 10" woofer with self treated cone + ribbon + 15" sub). Room was untreated, bare walls and windows and yet sound was marvelous with transparent sound stage and nearly no audible room reflections at midrange. That got me infected with OB virus right away and I started to ponder how to change my setup (with minimal impact to the wallet).
My present setup:
- 2.5 speakers with Bliesma B34 w/waveguide + 2*Satori MW16P-8 in closed box - designed by friend of mine
- 2 closed box subs with 10" Scanspeak SS 8565
- Purifi poweramp for 2.5 speakers
- Hypex plate amp for subs with hypex filters
Idea here is to make use of already present drivers (Bliesma + Satoris) in OB design together with suitable 15" woofer.
Any ideas and thoughts about feasibility, baffle size, crossover design, bass woofer selection etc. would be most welcome!
Thanks,

Alo


richidoo

Re: Hi
« Reply #1 on: 8 Apr 2022, 04:52 pm »
Hello Alo

Welcome to AudioCircle!

Something like this? ;)
http://www.htguide.com/forum/showthread.php?44276

I have those Satori woofers. They like vented better than sealed, but I don't know how they like free air. Any driver can be made to work in any application with enough EQ. :D  It has good motor so it can tolerate being manhandled by an amp and Purifi will make them submit.

The satori has good linearity at LF so it can be boosted. The baffle width determines the frequency of the portion of rolloff caused by diffraction. There is also dipole cancellation to cause rolloff as well as the natural rolloff due to falling acoustic impedance of the cone also which together make dipole rolloff steeper than sealed or ported box. So you will need to boost the LF of the satoris to get the F6 down into comfortable territory for your subwoofer. F6 at 80-100Hz is adequate given the bass driver can easily achieve 500Hz. This crossover frequency should be adjusted by ear to the richness you desire. Higher Fxo will be slightly richer until SEAS inductance starts to slow down the woofer and blur. But you have at least an octave or two above 100Hz, so no problem.

Your subwoofer is DIY with very capable driver with decently low coil inductance, so you can push the sub LP filter as high as you need to compliment Satoris. You are in good situation to try your experiment.  Some think dipole woofer must be high Q, and that is true if you will not apply EQ to boost the LF response. Then a high Q bass driver sloppiness allows natural self boost, but with the high cost of loss of damping. A well damped driver will maintain good detail when boosted and can handle the power and excursion for EQ boost. This is the wtg for dipole bass imo. Damping must be maintained in one way or another. Servo does it electrically, but mechanical damping is just as valid.

The only question is how will you apply the necessary EQ? Passive? analog active? or DSP active?
Beware the garage band speaker management in a box solutions like Behringer, as they do not have the fidelity you are accustomed to, nor that your ultra high end drivers and amp deserve. DEQX does have the fidelity and flexibility. But so does building custom analog filters for much less money, but significantly more time. Using all passive, speaker level filters will require good measurements, simulation to design and a large library of parts to fine tune the design. For dipole bass you need a lot of "boost" which means inductors and loss of gain in passive filter. Anything you can do with passive bass EQ is more easily done with active analog filter and then you maintain the electrical damping of bass as the speaker deserves.
I recommend this book for helping with analog filter design. Elliot Sound sells DIY PCB and plans to build several active crossovers of varying complexity. You can get a feel for what's required in your application by looking over his crossover and bass boost projects.

askevad

  • Newbie
  • Posts: 2
Re: Hi
« Reply #2 on: 9 Apr 2022, 07:18 am »
Thanks for the thumbs up!
Yes, it's link to my present speakers. Idea was to use Hypex filters with plate amp for 15" woofer.

richidoo

Re: Hi
« Reply #3 on: 9 Apr 2022, 05:35 pm »
Sounds good. I would make use of the 10" woofers too as they are sized well to add some mid-bass support to the dipole 6" drivers. With dipole you want as much cone area as possible in LF band. Separate dipole woofer will make scuplting bass EQ easier should you desire all passive xo main speakers.

The 10" stereo drivers can take you down below 80Hz in dipole then a single 15" sealed box can provide non directional deep bass and slam below 80. A pro audio woofer like Faital 15PR400 or similar.

Ideally, imo, use only one satori per side to minimize midrange lobing interference with tweeter,  then cross the satori to the 10" around 150-200Hz @2nd order. Adjust the sub plate amp to integrate 15" sealed with the 10" natural dipole rolloff. Put the 10" down low and the satori above the tweeter at ear height to minimize floor bounce interference, though the crossover freq might need a little higher than 200Hz for that strategy.