The Acoustic Resistance Frame with the Enviee and my EQ is linear phase.
The Step response shows a sharp rise and has a very wide " open time " of nearly 1.5mS.
That gives the ear ample time to focus on impulsive signals and " measure " 3 dimensional space if there is information on the recording. No multiple up and down going preasure events then in usual 2- or 3 - way systems.
There is no disturbance at " zero crossing " ( where presure goes through zero and then negative ), a problem that most boxed speakers have because the preasure from the membrane is bouncing back from the backwall.
In the longer time domain the Step response shows aperiodic behaviour. The preasure does not go positive again as in a reflex box. That comes from the gentle 6dB falling response of the frame and the low Qts of the driver. There is virtually no energy storage in the bass.
The rather flat group delay curve is just another view on the good time domain behavior. In simple words : all frequencies arive with the original timing.
I have seen a delay of more the 2mS @ 1kHz in so called " Reference Class " 3 way systems.
The Step response shows a sharp rise and has a very wide " open time " of nearly 1.5mS.
That gives the ear ample time to focus on impulsive signals and " measure " 3 dimensional space if there is information on the recording. No multiple up and down going preasure events then in usual 2- or 3 - way systems.
There is no disturbance at " zero crossing " ( where presure goes through zero and then negative ), a problem that most boxed speakers have because the preasure from the membrane is bouncing back from the backwall.
In the longer time domain the Step response shows aperiodic behaviour. The preasure does not go positive again as in a reflex box. That comes from the gentle 6dB falling response of the frame and the low Qts of the driver. There is virtually no energy storage in the bass.
The rather flat group delay curve is just another view on the good time domain behavior. In simple words : all frequencies arive with the original timing.
I have seen a delay of more the 2mS @ 1kHz in so called " Reference Class " 3 way systems.
Great drivers are arriving at my door at an astounding pace recently. After the introduction of the
ring radiators 15 years ago not much happened for a long time. There where the Tymphany LAT that failed to be successful although it worked great. The Mundorf AMTS that have reached maturity but are based on an old principle.
Of cause there are the Thiel ceramic and diamond drivers.
that has chnaged and now we have a flow of really great designs :
The SB Satoris, the Thiel Cell ( more to come ), the Enviee 2013 that proves for me that a linear, high sensitivity, low distortion wide band driver can be made without compromising the frequency response even to the highest treble and now the new Scan Speak 13" subwoofer. It is so low in distortion that Holger Barske measured it and said that this is the best sub he knows.
Here are some pictures.
I will build a cardiod woofer for the Enviee with it and also a very special dipole sub-sub woofer for my listening room that should have a response from 5Hz to 18Hz.
ring radiators 15 years ago not much happened for a long time. There where the Tymphany LAT that failed to be successful although it worked great. The Mundorf AMTS that have reached maturity but are based on an old principle.
Of cause there are the Thiel ceramic and diamond drivers.
that has chnaged and now we have a flow of really great designs :
The SB Satoris, the Thiel Cell ( more to come ), the Enviee 2013 that proves for me that a linear, high sensitivity, low distortion wide band driver can be made without compromising the frequency response even to the highest treble and now the new Scan Speak 13" subwoofer. It is so low in distortion that Holger Barske measured it and said that this is the best sub he knows.
Here are some pictures.
I will build a cardiod woofer for the Enviee with it and also a very special dipole sub-sub woofer for my listening room that should have a response from 5Hz to 18Hz.
Attachments
I think you're right. At frequencies below the lowest room resonance, there are only pressurisation effects. Your ears respond to pressure changes. Dipole woofers, or DP configurations, will not provide the high pressures required to register at such low frequencies. A few minute's work with the ripple tank simulator will convince you if you aren't sure.
Ripple Tank Simulation
Ripple Tank Simulation
Because i work on my sub-sub i am reading quite a bit of literature.
This is another way to drive the room :
DEBRA Distributed-EQ Bass Reflex Array, 5+ pieces- James Romeyn
It will not have any benefits under 20Hz though i think.
This is another way to drive the room :
DEBRA Distributed-EQ Bass Reflex Array, 5+ pieces- James Romeyn
It will not have any benefits under 20Hz though i think.
Here is an old Colloms piece but still interesting to read :
Basso Profundo | Stereophile.com
I am really into bass reproduction at the moment.
Basso Profundo | Stereophile.com
I am really into bass reproduction at the moment.
This is what i am playing around with at the moment.
I build this to get a measure on the new Accuton Cell midrange.
That is not the easiest driver i encountered. I worked quite a bit on the crossover.
The woofer section is the LAT cardioid i talked about. The tweeter is a gift from Michael Böresen so both drivers are not a commercial reality.
I build this to get a measure on the new Accuton Cell midrange.
That is not the easiest driver i encountered. I worked quite a bit on the crossover.
The woofer section is the LAT cardioid i talked about. The tweeter is a gift from Michael Böresen so both drivers are not a commercial reality.
Attachments
Now this is a really different approach... did you ever try something like that ?
No, but i think that Snell was a genius.
I may build it in the future. I think it needs a rather big room though. I heard it ones before 1980 on a HiFi show in Düsseldorf and it worked. The room was big. That was also the first time i heard a Platine Verdier so that was a memorable day.
Data-Bass
I may build it in the future. I think it needs a rather big room though. I heard it ones before 1980 on a HiFi show in Düsseldorf and it worked. The room was big. That was also the first time i heard a Platine Verdier so that was a memorable day.
Data-Bass