I hope people don't percieve this thread as me bragging around with a software I can't properly use.. Reason for posting this stuff is partly guidance on the journey, but also to inspire other fellow DIY'ers which have not used SPICE software in this manner before. I think it is a brilliant toolbox for speaker design, and it is not a heck of alot insightful information on the subject available online.. The only two good sources I have found is Marshall Leach's work and our fellow DIYer Svante..
I love it and can surely relate to the joy of being able to predict the behaviour of a loudspeaker!😀
Just an observation; when simulating the IEC baffle in Edge (same driver placement and distance as in the FR measurements, on axis), the lower end of the system (up to 1kHz) exhibits the same tendencies as the frequency response in the datasheet.. My immidiate thoughts on this is that the lower end of the L15RLY frequency response in fact is less ragged than what the datasheet gives impression of 🙂 With this in mind, I may not be too far off target if counting the FR below 1kHz as flat, before adding the step of my own baffle..
Rocky, I’m not sure you are convincing readers when writing:
Brilliant toolbox for speaker design, no, but useful for those who already have PSpice and don’t want to invest in a more dedicated loudspeaker modeling program.
That’s how far I can agree upon because it’s far more importance get knowledge from papers like the submitted *.
Although, simple lumped circuit modeling in PSpice can be great a tool to get a visual first hand look and for learning the very basic of speaker acoustic modeling,
I rather think it’s better to invest in a commercial proven Loudspeaker Modeling Program like SoundEasy and many more alike, together with a good Loudspeaker measurement system like CLIO and similar.
There is a turning point using PSpice when modeling speakers because you are often interested in what happens acoustically inside the speaker. **,***,****
There are many published attempts to do this in Pspice but often fail due to the use of too few and simple models.
The resulting preferably 3-D dispersion patterns from different real drivers when they are interacting are also of interest.
Most free simulation programs and textbook can’t provide this and when attempting, are simply not close enough.
More good reading and links:
**Marshall Leach, Electroacoustic-Analogous Circuit Models for Filled Enclosures”, JAES, Vol.37, No.7/8, 1989.
***Gavin Richard Putland, Modeling of Horns and Enclosures for Loudspeakers
*T/S model reading in prior to any PSpice modeling:
Already known at diyAudio.com: kelticwizard and richie00boy’s contributions to the free 'ReadResearch' for Neville Thiele and Richard H Small papers at: http://www.readresearch.co.uk/HTML/articles.htm.
A very useful paper I’ve not yet seen rec. at diyAudio.com:
****DRIVER DAMPING AND VARIATIONS OF THE CLOSED-BOX SYSTEM by Richard Small, Direct-Radiator Electrodynamic Loudspeaker Systems”, Ph.D.Thesis, The University of Sydney, May 1972. (Chapter 6, 7):
6.1 . Introduction to Derived Systems 6.1
6.2. Acoustic Damping of the Driver 6.2
6.3. The Densely-Filled Closed-Box System 6.3
6.4. The Resistance-Coupled Double-Cavity
Closed-Box System 6.4
6.5, The Leakage-Damped Closed-Box System 6.7
7. VARIATIONS OF THE VENTED-BOX SYSTEM
7.1. The Damped-Vent System 7.1
7.2. The Leakage-Damped Vented-Box System (ARU) 7.4
7.3. The Absorption-Damped Vented-Box System 7.6
7.4. The Damped-Box, Damped-Vent (Aperiodic) System 7.10
7.5. The Double-Cavity Vented-Box System 7.12
Last: The work of Martin J. King with great usability at: www.quarter-wave.com must be mentioned too.
B
Brilliant toolbox for speaker design, no, but useful for those who already have PSpice and don’t want to invest in a more dedicated loudspeaker modeling program.
That’s how far I can agree upon because it’s far more importance get knowledge from papers like the submitted *.
Although, simple lumped circuit modeling in PSpice can be great a tool to get a visual first hand look and for learning the very basic of speaker acoustic modeling,
I rather think it’s better to invest in a commercial proven Loudspeaker Modeling Program like SoundEasy and many more alike, together with a good Loudspeaker measurement system like CLIO and similar.
There is a turning point using PSpice when modeling speakers because you are often interested in what happens acoustically inside the speaker. **,***,****
There are many published attempts to do this in Pspice but often fail due to the use of too few and simple models.
The resulting preferably 3-D dispersion patterns from different real drivers when they are interacting are also of interest.
Most free simulation programs and textbook can’t provide this and when attempting, are simply not close enough.
More good reading and links:
**Marshall Leach, Electroacoustic-Analogous Circuit Models for Filled Enclosures”, JAES, Vol.37, No.7/8, 1989.
***Gavin Richard Putland, Modeling of Horns and Enclosures for Loudspeakers
*T/S model reading in prior to any PSpice modeling:
Already known at diyAudio.com: kelticwizard and richie00boy’s contributions to the free 'ReadResearch' for Neville Thiele and Richard H Small papers at: http://www.readresearch.co.uk/HTML/articles.htm.
A very useful paper I’ve not yet seen rec. at diyAudio.com:
****DRIVER DAMPING AND VARIATIONS OF THE CLOSED-BOX SYSTEM by Richard Small, Direct-Radiator Electrodynamic Loudspeaker Systems”, Ph.D.Thesis, The University of Sydney, May 1972. (Chapter 6, 7):
6.1 . Introduction to Derived Systems 6.1
6.2. Acoustic Damping of the Driver 6.2
6.3. The Densely-Filled Closed-Box System 6.3
6.4. The Resistance-Coupled Double-Cavity
Closed-Box System 6.4
6.5, The Leakage-Damped Closed-Box System 6.7
7. VARIATIONS OF THE VENTED-BOX SYSTEM
7.1. The Damped-Vent System 7.1
7.2. The Leakage-Damped Vented-Box System (ARU) 7.4
7.3. The Absorption-Damped Vented-Box System 7.6
7.4. The Damped-Box, Damped-Vent (Aperiodic) System 7.10
7.5. The Double-Cavity Vented-Box System 7.12
Last: The work of Martin J. King with great usability at: www.quarter-wave.com must be mentioned too.
B
Not trying to convince anyone, bjorno. Not at all. Actually, I'm pretty much done asking questions here now, so this thread is on it's final pages. My spice model is pretty much complete, I've ordered some electrets for a measurement mic so I can use measurements to aid the crossover design.. It's all good, really. I couldn't care less about who being convinced of what and why.. So that isn't really a problem for me. 😉
Reason I use PSpice is because I will use it next semester on school, so I need to get aquainted with it. I will not use SoundEasy at school as it's not related to my studies, and I don't want to pay for it either, so that is a bad idea and would be a waste of time and money for me, as I probably can't use it for much exept speakers anywayz. Still, I was impressed by PSpice with regards to speaker design, I like it much better than anything else I've tried.. I have not tried SoundEasy though, and unless you send me a free copy, I don't have that opportunity either. My student budget doesn't have the headroom needed to waste hundreds of dollars on software packages I don't use at school..
Reason I use PSpice is because I will use it next semester on school, so I need to get aquainted with it. I will not use SoundEasy at school as it's not related to my studies, and I don't want to pay for it either, so that is a bad idea and would be a waste of time and money for me, as I probably can't use it for much exept speakers anywayz. Still, I was impressed by PSpice with regards to speaker design, I like it much better than anything else I've tried.. I have not tried SoundEasy though, and unless you send me a free copy, I don't have that opportunity either. My student budget doesn't have the headroom needed to waste hundreds of dollars on software packages I don't use at school..
Rocky said:
Yes, I have often thought that measuring a driver in an IEC baffle is unfair towards the driver. I cannot really understand why some manufacturers do that, I mean the optimum response in an IEC baffle is not a flat one, but rather something like the one you have modelled in The Edge.
bjorno said:
Well, nothing stops him from doing both, right?
I think that one of the biggest advantages that Rocky is experiencing right now is actually understanding how the simulations work. Just using a piece of software that somebody else put together might give a more accurate result for a given configuration, but actually building the models by hand gives insights that are worth far more IMHO.
And as I said, he can do both, and that is a combination that is hard to beat by any fancy software.
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