It would be misleading to imply that response smoothness has any bearing on crossing into breakup.
One won't fix the other, so if they're each a problem they should be considered separately.
Most of these decisions are design decisions or preference.
The conventional approach is the design for the midwoofer to move as a rigid body. As the driver stops behaving in a pistonic manner, the first resonance can be seen as response irregularities. Thus the system design approach is to avoid this response; by crossing an octave or more below these resonances.
The alternative approach is to control these modal shapes, and consider it fine to have a few modes in the working range of the transducer, but this will extend bandwidth. This is evidenced in drivers such as the axiperiodic or BMR drivers.
In a way, this has been exploited for years in paper or poly cone electrodynamic drivers.
The conventional approach is the design for the midwoofer to move as a rigid body. As the driver stops behaving in a pistonic manner, the first resonance can be seen as response irregularities. Thus the system design approach is to avoid this response; by crossing an octave or more below these resonances.
The alternative approach is to control these modal shapes, and consider it fine to have a few modes in the working range of the transducer, but this will extend bandwidth. This is evidenced in drivers such as the axiperiodic or BMR drivers.
In a way, this has been exploited for years in paper or poly cone electrodynamic drivers.
Finally (almost) finished!
PTT8.0X08 and Viawave GRT-145W-8 in a closed box of 38lt. driven active by 4 Purifi amps and crossover 24db/oct at 2k
the box was..................................... a lot of work made from 24mm Birch ply, internally its more torus than sphere.
DSP is used to boost the bass, tune the sound to my 65 year old hearing and try to tame my very difficult room.
I am absolutely delighted with the result, They are extremely detailed, dynamic and imaging is pin sharp, wide and deep. The bass is fast and tight with good strong output down to 25-30hz the bass constantly surprises me. There is absolutely no hint of fatigue at any volume I care to listen at (a result I think of very low levels of distortion)
There are still gains to be made through DSP, but I think this is probably my final speaker project and I'm sure it's capable of showing any further improvements to the system.
Cheers Steve
.............................................................................................................
The triangle parts were cut by CNC as any errors to start would have been almost imposible to put right, everthing else was done with homemade jigs and a router.
PTT8.0X08 and Viawave GRT-145W-8 in a closed box of 38lt. driven active by 4 Purifi amps and crossover 24db/oct at 2k
the box was..................................... a lot of work made from 24mm Birch ply, internally its more torus than sphere.
DSP is used to boost the bass, tune the sound to my 65 year old hearing and try to tame my very difficult room.
I am absolutely delighted with the result, They are extremely detailed, dynamic and imaging is pin sharp, wide and deep. The bass is fast and tight with good strong output down to 25-30hz the bass constantly surprises me. There is absolutely no hint of fatigue at any volume I care to listen at (a result I think of very low levels of distortion)
There are still gains to be made through DSP, but I think this is probably my final speaker project and I'm sure it's capable of showing any further improvements to the system.
Cheers Steve
.............................................................................................................
The triangle parts were cut by CNC as any errors to start would have been almost imposible to put right, everthing else was done with homemade jigs and a router.
Attachments
Wow! Can I throw a pic (and a link to your post) in the OP? Beautiful work. This is the point where speakers and works of art truly collide, they are like sculptures!
Awe inspiring! That is one of the most beautiful objects that my eyes have been blessed with. That is pure love and devotion that you poured into your dream work. Glenn.
Nainframe, of course please do.
Thank you all for your very generous comments, I feel a bit overwhelmed, the basic idea for the sphere construction came from a chap on youtube.
Steve
I particularly like the photo where you are using a drill press to position a router motor. !!!
Has anyone tried the PTT6.5M midrange? I am building a 3 way and deciding between using the PTT6.5X that I already have as midrange, or should I get a PTT6.5M at extra cost. SPL wise, it is borderline. Depending on the passive crossover design it doesn't have a lot of SPL headroom matching with PTT8 woofer.
I have 6x PTT6.5M08 waiting for a mixed stereo/HT project in a WMTMW configuration.
I'm currently constructing a new ceiling with 6x Atmos speakers built in plus LED strip cove lights and bespoke DIY sound absorption panels. After that's finished I'll start building the speakers.
I'm currently constructing a new ceiling with 6x Atmos speakers built in plus LED strip cove lights and bespoke DIY sound absorption panels. After that's finished I'll start building the speakers.