Infinity QRS - Inspired Building These Speakers

[MagicMarksy]

Hi all,
I am following the many suggestions I have gotten over the past few days and I am going to commit some of my time and start some new threads. I am hoping that AudioKarma thinks these threads are valuable enough to make "STICKY" so they will be easy to find, as I expect they will be very popular.
So here goes. This is the first one. I have entitled it INFINITY QRS [Quantum Reference Standard] - Inspired US to Build these Speakers.
Many of you older memebers might remember back in the late 1970's (1978) that for a very limited period of time, Infinity actually made a product called the Quantum Reference Standard. This was only available for a very limited amount of time but it INSPIRED a whole array of loudspeakers that followed.
As the story goes.....the heart of the original QRS was the Strathern Midrange Driver. It is a pseudo-ribbon actually invented in the 1950's, if I recall correctly, and for many years it was manufactured in Northern Ireland.
The impedance of the midrange was only 0.55 Ohms so the manufacturer also devised a impedance matching transformer to use with the transducer, making the actual drive impedance of the combined device 8 Ohms. However, Arnie Nudell realized that if you took 3 raw drivers and put them in series you could get a 1.65 Ohm load and that a good high current amplifier could actually drive this load directly without the need for an impedance matching transformer. Eventually he mated 3 of these 2 foot Strathern midrange drivers with 20 Full Line Source EMIT's, that he had manufactured for him by Peerless Loudspeakers of Leominster, Massachusetts (13 facing front and 7 facing the rear), and mated them with a 15 inch woofer thus creating the INFINITY QUANTUM REFERENCE STANDARD soon to be known as the Infinity QRS'.
The next part of the story is that Harry Pearson, of Absolute Sound Fame, reviewed the speaker (Issue 13, 1978) and loved the midrange and high frequency components but thought the woofer was too sluggish to be a good mate for the system. It just so happened that at about the same time he was also reviewing the Audio Research / Magnaplanar Tympani 1D loudspeakers. In a moment of true genius he decided to try to mate the midrange high frequency portion of the Infinity QRS loudspeakers with the Bass panels from the Audio Research / Magnaplanar Tympani 1D loudspeakers and the rest is history.
Resources were limited at the time but he did figure out that the system sounded the best when BI-AMPED and as a crossover he used for the bi-amplification was the Dalquist DQLP1. If I remember correctly the crossover frequency chosen was about 150 Hz.
The combination was an instant success. In many people's opinion this was the first loudspeaker combination ever produced, that even began to approach the sound of LIVE MUSIC. A new name was then COINED for the combination speaker system he just created, and it was called the QRS-1D Hybrid System.
Once this happened, things began to move very quickly. Both Infinity and Audio Research / Magnaplanar took their current products off the market and both set about improving the short comings of each.
For Infinity this lead to the creation of the INFINITY REFERENCE STANDARDS ( IRS ) and for Audio Research / Magnaplanar this lead to the development of the TYMPANI IV's.
For us is the real world this was a great opportunity to BUILD OUR OWN version of the QRS-1D Hybrid System.
I was in Medical School at the time. I knew of Peerless and their development of the EMIT Tweeter for Infinity and KLH and I also knew about STRATHERN in Northern Ireland.
Using the Crewe, VA underground audiophile newspaper the "AUDIOMART" I ran some ads to see if I could interest enough people in helping me import some STRATHERN midranges into the USA from Northern Ireland ,and also went about getting the excess EMIT inventory from Peerless (when Infinity stuck them with it when they went to Japan to have the new EMIM and EMIT speakers manufactured).
I got about 12 people interested and I was eventually able to import, 1st about 24 then 48 and eventually some 96 or so Strathern Miodranges into the USA and I also procurred about 400 EMIT Tweeters from Peerless and ZALYTRON (the people Peerless unloaded them to, when they got stuck with them, when Infinity cancelled their orders and went to Japan to manufacture them). So from about 1982 and 1984 I sent people who were interested the parts to make their own verion of the QRS loudspeakers.
The heart of the speakers always was and always will be the Strathern Midrange Drivers. You could mate them with virtually any woofer to get the bass you needed and if you really desired you could supplement them with the EMIT tweeters for better high end dispersion.
Eventually I graduated from medical school and let Brian Chaney of VMPS Audio fame take over the importing of the Strathern Ribbons into the United States. In a deal to give him the import rights in about 1984, all I really wanted was a few more Strathern's at his cost. He gladly complied and I in turn, turned over the import rights for the Strathern Drivers to him.
I built many speakers using the Strathern Midranges and I will over time post many of them here in this thread. I also know of others from all over the world that did the same and I expect many will post their versions here as well. They kinda all resemble each other.
Of note Mike Desurkio (sp?) of "AUDIO CONCEPTS" also got into the game for a while and made some nice stand alone cabinets available to MAKE YOUR OWN version of the QRS as well. I even have still have a set to this very day.

From INFINITY:
Quantum Reference Standard

Introduced: 1977
Dimensions: 203 x 122 x 61 cm
Bass: 1 x 38 cm
Mids: 3 x EMIRM (Strathearn MRHF)
Highs: 20 x EMIT (7 on the back)
Suggested for amplifiers with: Bass: 150 Watts per channel
Mids/Highs: 100 Watts per channel
Frequency range: 18 Hz - 32 kHz
Crossover frequencies: 100 Hz, 4000 Hz
Suggested price (pair): 6500 $

Please feel free to edit this post and correct the grammer and the spelling. But I at least got it started like I said I would.
So everyone please chime in and enjoy.

Michael Marks

[MagicMarksy]

Well folks, it appears that there are two major varients to the way people have built there own versions of the Infinity QRS Speakers.
In one varient like this the speakers are placed in a stand alone column.
The woofer is then housed in a seperate cabinet or structure.
This varient works well and allows for quite varied room placement.
Here is a set built by Kurt Buhler who lives in Switzerland.
Kurt send me these pictures some time back so I am posting them here today for all to see.
I actually built some speakers very simliar to this in 1983.
I will post them as well as soon as I get a chance to dig up the pictures, scan them in, convert them to *.jpg files and upload them to this forum.
Once I do you will see how close our two sets came without knowing each other.
Notice one thing about Kurt's set.
He coverered them completely in FELT to reduce reflections.
This is something I did not do.
So enjoy Kurt's pictures.
I am posting them below.
The pictures include the passive crossover (in a stand alone box) that he made to go between the Strathern Midranges and the Infinity Full Line Source EMIT Tweeters, the Dalquist DQLP1 Crossover, and the Drapery Covering he placed over the speakers for decorative purposes.

[MagicMarksy]

This is the second varient of how many of us built our QRS-1D varients. In this method the QRS structure once built is actually attached in some way, to the Audio Research / Magnaplanar Tympani 1D speakers or at least the Bass Panels of them to make a completed unit.
This has the advantage of simplicity and that the bass panels can actually act as part of the wing structure that prevents the 180 degrees out of phase rear wave from the Strathern Midrange from interfering and canceling out the 0 degrees front wave.
These varients and often be made to stand up by themselves.
Room placement is often somewhat more limited, but the ease in which these home brews go together makes this variation simple to construct and always popular. Also sice the bass panels act as wings the cost of building the free standing structure to house the midranges is avoided markedly reducing the time it takes to manufacture these, and also avoids the need for superior wood working skills often needed to make the other style of stand alone uprights more difficult to constuct.
Again these are very similar to many QRS-1D varients I built from 1983 to date and I do not know who built these or when.
It just goes to show you that great minds think alike.
When I post my varients of this style you will be quite struck at how similar these all are, without even know each other.
So also enjoy this picture and I want to thank Charivari for making it available to me and us.

[MagicMarksy]

As I stated earlier I too made some stand alone QRS varients that are almost identical to the ones the Kurt Buhler in Switzerland made and we did not even know of each other back then. We both came up with the design independently. It is really suprising how similar they really are when you study them.
Mine of course I made out of Solid Teak.
I also used my special DIPOLE EMIT's that I build myself.
To make them you take two original Infinity / Peerless EMIT's apart, and reassemble them FRONT - Diapharam - FRONT to make them a true DIPOLE.
That means from every two EMIT's you start with you only end up with one, but since the EMIT's now radiates in DIPOLE fashon out of the front and the back, it makes up for the need to put tweeters on the rear of the speakers facing backward and thus makes up for at least some of the extra expense.
For these speakers I started with 60 Half Line Source EMITS and rebuilt 30 DIPOLE ones. I then used 15 per side. While these pictures show only the speakers with the grills in place I do have some that show the RAW drivers as well and when I dig them up I will add to this post.
Anyway, these speakers are now in Stamford, CT at Geoffrey Berg's house.
I sold them to him in 2000 when I bought my first set of real Infinity IRS Series III speakers.
He is pictured in one of the photographs. The speakers still sound great and he loves them. I love them too and I still get to hear them every time I go to visit.
So enjoy these pictures. As I dug out the old pictures to scan them in I looked at all the dates on the photographs. These photographs and speakers were make in 1984.

[MagicMarksy]

Here are some of my INFINITY QRS-1D Hybrid systems I built between 1982 and 1984. As I scanned in these pictures tonight I looked at the actual photo dates and relived some of the good old times in my memory. There is even a picture of me there, when I was a half naked hippie.
See how similar my original QRS-1D design looks when compared to the picture Charivari previously posted. The speakers are almost identical.
These speakers eventually evolved from their simplest form, 3 Strathern Ribbons per side, and eventually included the Audio Research / Magnaplanar Tympani 1-D woofers and the Infinity EMIT tweeters.
Eventually I rebuilt the tweeters in DIPOLE format and finally these dissappeared evolving into the stand alone TEAK speaker columns I previously posted earlier in this section.
I will post even more later on.
Speakers I built for other people over this time period.
For now, enjoy these photos and think about what you too can do with a little time and effort.

[MagicMarksy]

Here is the evolutionary process involving the QRS-1D Hybrid Speakers I built for Arnold Wiseman of Washington, DC in 1982/83.
These evolved similar to mine but never beacame stand alone columns.
These always remained attached to the Tympani 1-D woofer panels for simplicity.

[MagicMarksy]

Here are the speakers I made for Nathan Tickel in 1982. Nathan was on a budget and as you recall the tweeters are not really necessary. The tweeters just add high end dispersion not high end frequency respose and he did not have the extra money to spend and he was quite happy with the result. So was I. Notce also how we used the spare wing of the Tympani 1-D speakers as an extra baffle for the midranges. It ended up working quite well and I've done the same trick several times since then. It really simplifies construction and makes use of all the product lying around without discarding anything or spending time and money building something unnecessary that you already have to start with....so why not use it...right?

[MagicMarksy]

Bob and I talked Michael Debukio (sp?) at Audio Concepts into making these cabinets special for Bobby Sattin so he could use them in stand alone custom speakers. Bobby was cost consious, never felt the tweeters were necessary, as I previous stated and decided to do without them in this, the final version of his speakers. He used Large Advent Speakers for the Woofers and is still to this day quite happy with the result. He still ownes them today, 24 years later and they sound better tha ever....still state of the art even at today's standards.

[MagicMarksy]

Please also see these posts for additional details and information about my Infinity DIPOLE EMIT tweeter upgrade.

http://www.audiokarma.org/forums/sho...t=65571&page=3

[MagicMarksy]

I feel that the modifications I do to the Infinity RS-1b speakers also fit into this catagory. So please also follow this link to go there to learn more about this process as well.

http://www.audiokarma.org/forums/sho...d.php?t=124068

[shrinkboy]

now here's a thread for the inquiring minds--

[MagicMarksy]

In my opinion if it were not for the Strathern speakers made in Northern Ireland and the Infinity QRS that Arnie Nudell made out of them there would never have been EMIT's and then EMIM's.
Without EMIM's there would never have been the IRS Series of speakers, no RS series (RS-1, RS-1a, RS-1b, RS 1.5, RS 2.5a, RS 2.5b, RS 4.5b), and no IRS Beta, IRS Gamma, or IRS Delta, etc.

So you might as well go here as well:

http://www.audiokarma.org/forums/sho...=63523&page=12

to learn about some of these speakers.
As they were, in my humble opinion, all inpired by the original QRS'.

[MagicMarksy]

While I was going through all my papers organizing material for this posting I ran across some old information I dug up on the Strathern Drivers that John Lipp, Ph.D. posted on his web site back in 1999.
This is very useful information and also very informative.
So provided here are two links to his site.
The first one is a test set up he used to make some measurements of the Strathern Drivers with his observations, test results and conclusions.

http://www.lippaudio.org/Strathearne/intro.html

The second one is a copy of the Manual that VARIS AUDIO provided with the STRATHERN DRIVERS when they bagan to resell them.

http://www.lippaudio.org/Strathearne/manual.html

Both are very informative and useful so I post them here to share and to make them easy for all to find.

[MagicMarksy]

In 1982 I set about tracking down some original Infinity / Peerless EMIT tweeters so I could build, and help others build, the QRS-1D speaker systems.

I dug out some of my original notes and scanned them in and have posted them here for all to now see.

It appears that I was on a mailing list for the company Universal Sound out of Sarasota, Florida.

They bought some surplus EMIT's from Peerless when Infinity canceled their contact with Peerless, leaving Peerless with excess inventory.

Once I knew this I was able to contact Janet Baker at Peerless and find out that Peerless sold the excess EMIT inventory to Universal Sound, Zalytron, Toutant Electric and International TV Company.

I contacted each for quantity and pricing and ended up purchasing a large number of EMITs for my projects from Zalyton.

Here is some of the original information I dug up in 1982 which I am now making readily available for eveyone to finally see.

[holland]

What a nice and comprehensive outline. I own for many many years Quantum 4. However, the midtoners are in a terminal stage# 902-0206 Dome Midtoners. Suggestions to handle this issue are welcome.