First speaker to reproduce a 60hz sq wave

[Fredrickj]

I've been developing a new speaker design which I am preparing for the next few audio shows on the west coast. Fourier Transform Speakers can not only produce 60hz square waves with large cone drivers but also complex multi-waveform signals at virtually undetectable distortion levels. They match the distortion levels of the very best planar or electrostatic headphones available, matching their sound characteristics perfectly. And they will not cost a fortune. I'm posting as I am thinking of producing a product that is designed to be coupled with any good bookshelf speaker. Why dump them when they are quite possibly just fine above 1k hz. After all, even $700,000 speakers often only have a single midrange and tweeter. (Magic M-9). My thousands of hours experimenting has made it clear that the first 1K hz is by far the most important in determining the quality of a speaker. That is why the finest speakers are so expensive. That first 1khz is so challenging since that not only is where the energy is that makes cabinets and drivers so expensive, but also those frequencies that make the biggest difference in speakers by a very wide margin. The 20hz to 1K hz modules allows the bookself speaker to sing like never before when they are relieved of producing the bottom 1Kz.

Sound interesting for you with great Bookself speakers?

Check out the my speakers output compared to input signal shown on left. REW.

By the way, I'm a no nonsense designer that believes in blind testing and science. We need more common sense and science in this hobby.

Fourier Transform Speakers.

 

[amirm]

Please don't keep editing your post. It goes back into moderation queue.

 

[Anton D]

At which shows will you be exhibiting?

Sounds interesting.

Your concept plus an AMT could be full range.

 

[YSC]

Sounds interesting on paper, but any kind of pre production unit look of it? and more importantly, maybe it's translation problem, do you mean it's kind of a subwoofer? coz you mentioned using it with bookshelf, but if it isn't sub crossing below 100hz at most localization will be a problem so you are forced to use your new speaker as a speaker stand, which, the acoustic center height could be a big problem.

 

[antcollinet]

The Gibbs waveform on that square wave suggests a top end roll off of 420 to 500Hz - would that be about correct for the measured unit?

 

[Matt_Holland]

Forgive my ignorance, but how can you reproduce any frequency square wave with low distortion without an extremely wide bandwidth? Or is the assumption that the additional >1KHz speaker necessary to complete the picture? And if so, what specs are necessary for it to match your woofer(s)?

 

[unpluggged]

Sound interesting for you with great Bookself speakers?

No.

 

[Fredrickj]

At which shows will you be exhibiting?

Sounds interesting.

Your concept plus an AMT could be full range.

I have a full range with planar's 1khz to 3K hz and amt a tweeter above 3K hz. And while I've built state of the art speakers utilizing the Fourier Transform principles up to over 3K, a sound that is identical to my $2K+ planar headphones in every respect, (except the music is in front of me and not inside my head) the difference between that full range speaker and good bookshelf speaker combined with my bass/lower mid module is not much. The difference is miles from the difference between the bookshelf's alone vs couples with my module. Only the most exacting audiophile would think the difference in price worth my full range speakers vs my bass module w their own bookshelf speakers. My belief in the importance of the bottom 1khz was confirmed dramatically first time I heard my Elac Unify 2's couples and rolled off at 1k hz with the >1K hz bass module.

 

[Fredrickj]

Forgive my ignorance, but how can you reproduce any frequency square wave with low distortion without an extremely wide bandwidth? Or is the assumption that the additional >1KHz speaker necessary to complete the picture? And if so, what specs are necessary for it to match your woofer(s)?

A square wave is composed of an infinite number of odd harmonics of a fundamental frequency sign wave. In infinite number odd harmonics will produce the perfect square wave you see in the generator, If a speaker like my Fourier Transform speakers can produce enough pure sign wave odd harmonics of a 60hz fundamental, then you will produce a sign wave. A tall ask for any speaker that I know of, until now that is.

 

[antcollinet]

A square wave is composed of an infinite number of odd harmonics of a fundamental frequency sign wave. In infinite number odd harmonics will produce the perfect square wave you see in the generator, If a speaker like my Fourier Transform speakers can produce enough pure sign wave odd harmonics of a 60hz fundamental, then you will produce a sign wave. A tall ask for any speaker that I know of, until now that is.

But it is only producing up to about 7th 6th (7 x fundamental) Harmonic of 60Hz.

 

[voodooless]

As long as it’s not a point source speaker, a square wave will only be valid in the sweet spot. Any deviation from it will mangle the square wave. You can do this with any speaker with a bit of convolution.

 

[Fredrickj]

Sounds interesting on paper, but any kind of pre production unit look of it? and more importantly, maybe it's translation problem, do you mean it's kind of a subwoofer? coz you mentioned using it with bookshelf, but if it isn't sub crossing below 100hz at most localization will be a problem so you are forced to use your new speaker as a speaker stand, which, the acoustic center height could be a big problem.

I am building the bass/mid module now. Height of the bookshelf speakers will be about the same as any other speaker costing upwards of $50k and more. The actual mid range driver and tweeter in the bookshelf speakers will be about 36 to 40" off the floor depending on my final design. The speaker I used to test my theory's are the drivers operating below 1K hz, 5 of them, of my full range Fourier Transform speakers.

 

[Fredrickj]

But it is only producing up to about 7th Harmonic of 60Hz.

I went up 9 harmonics, 60 fundamental, 180, 300, 420, 540, 660, 780, 900, 1020, 2040.

 

[Matt_Holland]

A square wave is composed of an infinite number of odd harmonics of a fundamental frequency sign wave. In infinite number odd harmonics will produce the perfect square wave you see in the generator, If a speaker like my Fourier Transform speakers can produce enough pure sign wave odd harmonics of a 60hz fundamental, then you will produce a sign wave. A tall ask for any speaker that I know of, until now that is.

To reproduce a square wave a speaker needs to be able to reproduce: fundamental F Hz to infinity Hz. There is nothing stopping any loudspeaker approaching a close approximation of a square wave. The closeness of the approximation depending on the speaker's bandwidth and self distortion.

Tell us more about your design. At the moment I’m assuming it’s just a big, high quality conventional woofer, or multiples of.

 

[Fredrickj]

I went up 9 harmonics, 60 fundamental, 180, 300, 420, 540, 660, 780, 900, 1020, 2040.

Even so, 7 perfect sign waves will produce a square wave almost identical to the one shown. Only thing that changes as the odd harmonics increase is the small waveforms between the vertical rise will get smaller and approach a smooth line when you get up 10k and above.

 

[FrantzM]

Hi

Looking forward to read more about your speaker..
The Quad ESL 63 could reproduce a 1 KHz square wave .

.. I would imagine that 60 Hz would not be a problem for it, since the 20th harmonic would be only at 1200 Hz ... I could be wrong...

Happy holidays!

Peace.

 

[antcollinet]

I went up 9 harmonics, 60 fundamental, 180, 300, 420, 540, 660, 780, 900, 1020, 2040.

But the highest frequency content of the waveform shown is 7x60Hz (count the peaks in the Gibbs wafeform) = 420Hz. That is 6th Hamronic with only the 2nd, 4th and 6th present (odd multiples) - so only 3 sinewaves.

 

[Hayabusa]

I've been developing a new speaker design which I am preparing for the next few audio shows on the west coast. Fourier Transform Speakers can not only produce 60hz square waves with large cone drivers but also complex multi-waveform signals at virtually undetectable distortion levels. They match the distortion levels of the very best planar or electrostatic headphones available, matching their sound characteristics perfectly. And they will not cost a fortune. I'm posting as I am thinking of producing a product that is designed to be coupled with any good bookshelf speaker. Why dump them when they are quite possibly just fine above 1k hz. After all, even $700,000 speakers often only have a single midrange and tweeter. (Magic M-9). My thousands of hours experimenting has made it clear that the first 1K hz is by far the most important in determining the quality of a speaker. That is why the finest speakers are so expensive. That first 1khz is so challenging since that not only is where the energy is that makes cabinets and drivers so expensive, but also those frequencies that make the biggest difference in speakers by a very wide margin. The 20hz to 1K hz modules allows the bookself speaker to sing like never before when they are relieved of producing the bottom 1Kz.

Sound interesting for you with great Bookself speakers?

Check out the my speakers output compared to input signal shown on left. REW.

By the way, I'm a no nonsense designer that believes in blind testing and science. We need more common sense and science in this hobby.

Fourier Transform Speakers.

lots of talk, not much real information... and the square wave does not look too impressive...

 

[Fredrickj]

To reproduce a square wave a speaker needs to be able to reproduce: fundamental F Hz to infinity Hz. There is nothing stopping any loudspeaker approaching a close approximation of a square wave. The closeness of the approximation depending on the speaker's bandwidth and self distortion.

Tell us more about your design. At the moment I’m assuming it’s just a big, high quality conventional woofer, or multiples of.

You don't see manufactures posting square waves in the bass region is because they can't. Their design limits their ability no matter how much they spend on massive magnets, super light cone materials etc. these expensive custom drivers do improve their performance but they still cannot defeat the laws of physics. I do use off the shelf cone drivers, the largest is a single 15" eminence. A good but a nothing special driver. But that is the only thing I have in common with other speakers on the market. I use good cone drivers.

 

[Fredrickj]

lots of talk, not much real information... and the square wave does not look too impressive...

pump a 60hz sq wave into your speakers and see what you get.