• WANTED: Happy members who like to discuss audio and other topics related to our interest. Desire to learn and share knowledge of science required as is 20 years of participation in forums (not all true). Come here to have fun, be ready to be teased and not take online life too seriously. We now measure and review equipment for free! Click here for details.

A bit about your host....

Joined
Nov 24, 2019
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India
#81
Thanks for starting this site. I have enjoyed the learning. Also a suggestion is dont discard the Pink Panther ever. The Reviews with PP are famous and potential to become even more so, years down the line. It is visually distinct from other forums and arouses basic curiosity about the product in review and having different poses resonates with the technical review. A unique identity. Whether it was deliberate or things fell in right places; from advertising point of view it is very clever and smart thing. Best wishes to the future.
Regards
 
Joined
Mar 24, 2020
Messages
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#82
This is a bit about your host, Amir Majidimehr. I am writing this as to give more context to people reading my technical reviews and measurements. I have realized that without this context, many assume I am yet another blogger spitting out graphs. That is very true but let’s see if we can confuse them with an alternate reality!

Without giving away my exact age, I grew up in 1960s with analog electronics as my primary hobby. Learned that from my oldest brother who likewise had the same hobby and spent his nights and days designing electronics. This gave me an intuition for analog electronics which to this day serves me better any textbook or formal education.

Speaking of formal education, I naturally aimed to get an Electrical Engineering degree which I received in early 1980s (still trying hard to not give away my age!). During that time though, the personal computer revolution was upon us and I quickly fell in love with my second hobby: software. I programmed my Apple II and later managed the computer lab at the college where I wrote a bunch of custom software including an editor all the students used to write their programs.

During schooling, I worked at an electronics repair shop, fixing everything from audio equipment to VHF radios. That childhood experience really got cemented combined with a new skill of having to troubleshoot equipment, usually with no schematic. All in all, I repaired hundreds of pieces of equipment, getting a good feel for quality engineering versus not.

Back to the degree, once I graduated, the first job I found was actually software, not engineering. I became a Unix “kernel” (Operating system) developer working on then new, Unix operating system. That gave me another baptism by fire having to learn nearly half a million lines of code with nary any documentation. This was at a large minicomputer company producing systems costing nearly $300,000. Kernel work gets you pretty close to hardware and during that time, I got a very deep understanding of it. This was a good thing as Unix became the foundation for much of what we use today from Linux to Android, MacOS and Windows.

In late 1980s I had an opportunity to work at the computer division of Sony. Initially the job was building a software team to develop Unix but we proposed and won approval to design and build our own hardware to go with it. There we went deep, developing our own ASICs (large scale custom electronic IC), motherboards, audio subsystem, power supply, LCD display etc. Working for Sony was great as at that time they were in their peak of success and their quality standards were quite high. We combined that with great engineering from US in silicon valley and really pushed state of the art in design and simulation at that time.

It was during that time that I got exposed to products of a then new company, Audio Precision (AP). They had overnight obsoleted audio measurement products from likes of HP (now Agilent/Keysight). I bought one for the team but I was the only one who learned to use it. It cost a cool $25,000 which at the time (early 1990s) was quite a lot of money. Still is today.

Sony fell on hard times after acquiring Columbia Pictures so my team was let go. I was offered to stay there but I got bored and left. In return for some consulting though, I got to keep that original AP (which I later gave to my brother -- the unit I have now is much newer).

Having developed my hardware skills, the next two companies I worked for also developed hardware and software: Abekas Video Systems and Pinnacle (now part of Avid). There, I managed hardware, firmware and software engineers development high-end hardware for real-time effects, switching, graphics, editing, etc. I am fortunate enough to have managed a very smart team which won two technical Emmy Awards.

By then a new development was happening: the web. I had worked extensively on networking which was the underpinning of the Internet. The advent of browsers took that to a new level and I wanted to be a part of that. So when my ex-boss from Akekas called me to say he was leading a Stanford-university start-up that was streaming video on the web, I jump at the chance to lead engineering there.

This was in the days of dial-up modems and trying to send video and audio through such slow link was nothing short of a miracle. Still, we managed to do it well enough that the company got acquired by Microsoft back in 1997 (https://news.microsoft.com/1997/08/...timedia-strategy-with-release-of-netshow-2-0/).

I specialized at Microsoft in driving our technology through other products than just the PC. At the time everyone was the enemy of Microsoft it seemed so it was a big challenge. At the end, we did it with our products literally shipping billions of other devices and every Blu-ray player. Only Apple refused to ship and use it. To date, those products all generate significant royalty stream for Microsoft, long after I am gone from there.

During my time at Microsoft, as VP of Digital Media Division, I grew to manage a division of nearly 1000 engineers, testers, marketing and business development people. One of the groups I managed though was the signal processing team which produced audio and video compression technologies. Both of those relied on refreshing my knowledge of the core signal processing science back in college and learning a ton more about new domains like psychoacoustics. Formal and controlled testing was a part of that just the same. Through training, I became an “expert” in finding difficult audio distortions that many could not. This training is serving me well to this day in being able to pass audio objectivist challenges of blind tests of small distortions.

I am very proud of the accomplishments of my team at Microsoft as it led to winning yet another technical Emmy award (see https://flic.kr/p/x72F4 . I am the one on the right). I also received an incredible education working with my many top engineers from audio processing to streaming and audio subsystem in the OS.

I retired from Microsoft back in 2007 (officially left in 2008) and created a start-up which was acquired by Fortune 50 companies. I currently own a system integration company, Madrona Digital, that does security, audio/video, lighting, networking, etc. for mid to high-end homes and commercial buildings (no retail sales). This gives me great exposure to the industry and the “back story” of it.

So what does this all mean? Well, it means that I am very familiar with many aspects of the systems we talk about. I am comfortable talking about networking and streaming one minute, and good power supply design the next. Hey, we could even talk about patents, business aspects, etc.

No, it doesn’t mean I know more than anyone in these fields. Many people have more experience than me in their deep vertical. What it means is that I have a broader set of experiences than most, and I have the knowledge to dig deep and analyze what is going on after some 40 years of being immersed in all aspects related to audio and technology.

Here is a list of technologies I feel very comfortable in:

1. Computer architecture, hardware design, networking, operating system, memory management, system architecture, etc.

2. Internet protocols and streaming technologies

3. Audio/Video signal processing, compression, psychoacoustics, controlled/blind testing

4. Analog and digital electronics

5. Sound reproduction in rooms (learned post retirement from some of the best teachers one can have such as Dr. Floyd Toole)

6. Audio measurements and analysis.

7. Bad sense of humor which you will see peppered in most of my writing.


So there it is. No more complaining about who this idiot is that is writing these articles.
[email protected] - now that's what I call an Introductory post!
 
Joined
May 8, 2020
Messages
30
Likes
9
#86
This is a bit about your host, Amir Majidimehr. I am writing this as to give more context to people reading my technical reviews and measurements. I have realized that without this context, many assume I am yet another blogger spitting out graphs. That is very true but let’s see if we can confuse them with an alternate reality!

Without giving away my exact age, I grew up in 1960s with analog electronics as my primary hobby. Learned that from my oldest brother who likewise had the same hobby and spent his nights and days designing electronics. This gave me an intuition for analog electronics which to this day serves me better any textbook or formal education.

Speaking of formal education, I naturally aimed to get an Electrical Engineering degree which I received in early 1980s (still trying hard to not give away my age!). During that time though, the personal computer revolution was upon us and I quickly fell in love with my second hobby: software. I programmed my Apple II and later managed the computer lab at the college where I wrote a bunch of custom software including an editor all the students used to write their programs.

During schooling, I worked at an electronics repair shop, fixing everything from audio equipment to VHF radios. That childhood experience really got cemented combined with a new skill of having to troubleshoot equipment, usually with no schematic. All in all, I repaired hundreds of pieces of equipment, getting a good feel for quality engineering versus not.

Back to the degree, once I graduated, the first job I found was actually software, not engineering. I became a Unix “kernel” (Operating system) developer working on then new, Unix operating system. That gave me another baptism by fire having to learn nearly half a million lines of code with nary any documentation. This was at a large minicomputer company producing systems costing nearly $300,000. Kernel work gets you pretty close to hardware and during that time, I got a very deep understanding of it. This was a good thing as Unix became the foundation for much of what we use today from Linux to Android, MacOS and Windows.

In late 1980s I had an opportunity to work at the computer division of Sony. Initially the job was building a software team to develop Unix but we proposed and won approval to design and build our own hardware to go with it. There we went deep, developing our own ASICs (large scale custom electronic IC), motherboards, audio subsystem, power supply, LCD display etc. Working for Sony was great as at that time they were in their peak of success and their quality standards were quite high. We combined that with great engineering from US in silicon valley and really pushed state of the art in design and simulation at that time.

It was during that time that I got exposed to products of a then new company, Audio Precision (AP). They had overnight obsoleted audio measurement products from likes of HP (now Agilent/Keysight). I bought one for the team but I was the only one who learned to use it. It cost a cool $25,000 which at the time (early 1990s) was quite a lot of money. Still is today.

Sony fell on hard times after acquiring Columbia Pictures so my team was let go. I was offered to stay there but I got bored and left. In return for some consulting though, I got to keep that original AP (which I later gave to my brother -- the unit I have now is much newer).

Having developed my hardware skills, the next two companies I worked for also developed hardware and software: Abekas Video Systems and Pinnacle (now part of Avid). There, I managed hardware, firmware and software engineers development high-end hardware for real-time effects, switching, graphics, editing, etc. I am fortunate enough to have managed a very smart team which won two technical Emmy Awards.

By then a new development was happening: the web. I had worked extensively on networking which was the underpinning of the Internet. The advent of browsers took that to a new level and I wanted to be a part of that. So when my ex-boss from Akekas called me to say he was leading a Stanford-university start-up that was streaming video on the web, I jump at the chance to lead engineering there.

This was in the days of dial-up modems and trying to send video and audio through such slow link was nothing short of a miracle. Still, we managed to do it well enough that the company got acquired by Microsoft back in 1997 (https://news.microsoft.com/1997/08/...timedia-strategy-with-release-of-netshow-2-0/).

I specialized at Microsoft in driving our technology through other products than just the PC. At the time everyone was the enemy of Microsoft it seemed so it was a big challenge. At the end, we did it with our products literally shipping billions of other devices and every Blu-ray player. Only Apple refused to ship and use it. To date, those products all generate significant royalty stream for Microsoft, long after I am gone from there.

During my time at Microsoft, as VP of Digital Media Division, I grew to manage a division of nearly 1000 engineers, testers, marketing and business development people. One of the groups I managed though was the signal processing team which produced audio and video compression technologies. Both of those relied on refreshing my knowledge of the core signal processing science back in college and learning a ton more about new domains like psychoacoustics. Formal and controlled testing was a part of that just the same. Through training, I became an “expert” in finding difficult audio distortions that many could not. This training is serving me well to this day in being able to pass audio objectivist challenges of blind tests of small distortions.

I am very proud of the accomplishments of my team at Microsoft as it led to winning yet another technical Emmy award (see https://flic.kr/p/x72F4 . I am the one on the right). I also received an incredible education working with my many top engineers from audio processing to streaming and audio subsystem in the OS.

I retired from Microsoft back in 2007 (officially left in 2008) and created a start-up which was acquired by Fortune 50 companies. I currently own a system integration company, Madrona Digital, that does security, audio/video, lighting, networking, etc. for mid to high-end homes and commercial buildings (no retail sales). This gives me great exposure to the industry and the “back story” of it.

So what does this all mean? Well, it means that I am very familiar with many aspects of the systems we talk about. I am comfortable talking about networking and streaming one minute, and good power supply design the next. Hey, we could even talk about patents, business aspects, etc.

No, it doesn’t mean I know more than anyone in these fields. Many people have more experience than me in their deep vertical. What it means is that I have a broader set of experiences than most, and I have the knowledge to dig deep and analyze what is going on after some 40 years of being immersed in all aspects related to audio and technology.

Here is a list of technologies I feel very comfortable in:

1. Computer architecture, hardware design, networking, operating system, memory management, system architecture, etc.

2. Internet protocols and streaming technologies

3. Audio/Video signal processing, compression, psychoacoustics, controlled/blind testing

4. Analog and digital electronics

5. Sound reproduction in rooms (learned post retirement from some of the best teachers one can have such as Dr. Floyd Toole)

6. Audio measurements and analysis.

7. Bad sense of humor which you will see peppered in most of my writing.


So there it is. No more complaining about who this idiot is that is writing these articles.
Can you ban me for good please.
 

RayDunzl

Major Contributor
Central Scrutinizer
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#87
Joined
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Location
Toronto, ON, Canada
#91
RESPECT TO YOU SIR
I have a EE degree and currently working as a full stack developer. Your successes are my goals Amir.
 

davidc

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#92
I can’t seem to be able to do this. If I like the music, I get distracted and can’t code. If I don’t like the music, I get distracted and can’t code. I’ll have to find some music that is just okay, ha ha.

I do work from home a lot so it’s easier to get focused coding time.
I know this thread is a year old but...I am the same way. Music simply distracts me. I want to listen to it. The most I can have is a TV droning in the background. I noticed this all the way back in elementary school doing homework.
 

davidc

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#93
Amirm, you are a learned man. A man whose work and opinion should be respected. And appreciated.

Add in a good sense of humor, objectivity, rationality, practicality, and you've created a great website and forum.

I'm guessing you are a year or three older than me. As an audiophile from my second decade of life, I grew up with objective bench testing reviews, so you are right up my alley. It's really nice to have someone doing them. Correctly. My dad, an electronics engineer, taught me this hobby. I almost became an electronics engineer myself, but as I went through the end of high school and beginning of college, the natural sciences pulled me away from the physical sciences and I became a doctor.

You've stated you've study psychoacoustics a lot...have there been any studies about the decline in hearing as we age, especially frequency response, and how it changes the perceived hearing itself? Meaning, that many men that are audiophiles, as they age, the high-frequency response of the their auditory system declines dramatically, yet, they don't seem to complain about it.

Yet, if an audio system had a frequency response curve like that, 99% of people would notice it doesn't sound well.

Psychoacoustics is amazing. I have a Burwen 1201A Noise Reduction unit. It was a great attempt at getting rid of LP and tape hiss. Then along came Bob Carver with his Autocorreatior. And ingenious and extremely effective device. Got one of those too. Also, the Garrard (and the more effective SAE) click and pop reducer. I have the Garrard and it worked pretty damn well. SAE made some pretty elaborate dynamic range expanders, but I never had one.

Then Bob Carver again with his Sonic Holography (gotta hand it to his naming things, lol). Very effective at expanding the soundstage, but hypercritical in physical positioning. And Arnold Klayman at Hughes (of all companies) with his SRS Sound Retrieval System. Wow! But, sounded pretty weird with a lot of stuff, yet I ended up with a couple of the home units and computer add-ons, and even a car unit!

At the moment, I have a 10 yr old Alpine head unit that I plan to put in one of my cars that has an Audyssey type processor. It never sold well, and I never saw a test report, but I thought I'd try it.

Also, Kicker, a car audio company, is the first to come out with an Audyssey type system for the car. I haven't heard it yet, but it's incorporated with their amps, and it's pretty inexpensive. It must be pretty good, as even inexperienced listeners in informal tests have thought it sounded great.

I remember a CES back in the 1990s when AR said it was going to introduce an active equalizer with a microphone that would EQ a room as the music played. I saw the prototype there, but it was never introduced.

Even Bob Carver in his current speaker line up, claims to have introduced Sonic Holography into the speakers (in a more subtle way), by using extra speakers like Polk tried with their SDA lineup. Carver's new speakers also claim to have a room EQ system built-in by using an extra line of speakers on the side of the cabinet. Using these speakers back EMF as a microphone, with the signal going back to his external active crossovers and amp, they generate a correction curve applied back to the signal. I have seen him say this in a society meeting video, but there is little more written about it. Very interesting though...

Wow, did I just write all that? Sorry about that. Audio, signal processing, psychoacoustics, and room correction have always been very interesting to me.

Now I'm gonna drill down into the Psychoacoustics subforum here.

Thanks again...you know...even the XenPorta 2 PRO forum software has to be the best I've come across. There are so many little things about how it works that are just quicker and smarter than any other forum software I've used.
 
Last edited:

bt3

New Member
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#94
You have an interesting background.
Just curious. Have you read Licklider's book - The Dream Machine?
 

davidc

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#95
You have an interesting background.
Just curious. Have you read Licklider's book - The Dream Machine?
No, I haven't. But, I just downloaded it into my Audible Books account, so I'll listen to it soon. I wouldn't be surprised my dad had met him at some point. My dad was in aerospace his whole life and dealt a lot with the government, especially with respect to computer development. I wish I could ask him, but he passes away in 1991
 

j_j

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#96
Amirm, you are a learned man. A man whose work and opinion should be respected. And appreciated.

Add in a good sense of humor, objectivity, rationality, practicality, and you've created a great website and forum.


...
Now I'm gonna drill down into the Psychoacoustics subforum here.

Thanks again...you know...even the XenPorta 2 PRO forum software has to be the best I've come across. There are so many little things about how it works that are just quicker and smarter than any other forum software I've used.
Well, I'm not Amir, but you asked a lot of complicated questions that fall in my particular area. This isn't the place for them, though, they belong maybe in the hearing section?
 
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amirm

amirm

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Thread Starter #97
Even Bob Carver in his current speaker line up, claims to have introduced Sonic Holography into the speakers (in a more subtle way), by using extra speakers like Polk tried with their SDA lineup. Carver's new speakers also claim to have a room EQ system built-in by using an extra line of speakers on the side of the cabinet. Using these speakers back EMF as a microphone, with the signal going back to his external active crossovers and amp, they generate a correction curve applied back to the signal. I have seen him say this in a society meeting video, but there is little more written about it. Very interesting though...
Thanks for the kind words. Bob came to our audio society and said the same thing. I could not make sense out of what he was saying though. I post my impressions here: https://www.audiosciencereview.com/...er-and-his-amazing-line-source-speakers.1261/
 
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