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Voicing of the original Goodmans Maxim mini-monitor

ToTo Man

ToTo Man

the band not the dog
I've had the opportunity to listen to and measure three examples of these famous mini monitors in recent years, and they all displayed the same, rather unusual voicing. There is approximately a 6dB tilt (in the wrong direction!) between the lower and upper frequencies, which gives this speaker a very bright and lean timbre. I have also included measurements of the Double Maxim and JR149 as comparison:

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The Maxim's published frequency response reveals a similar trend, but not quite as extreme as my measurements:
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According to Jerry Bloomfield's recent lecture at RMAF 2018, the BBC considered using the Maxim but rejected it due to manufacturing inconsistencies. In light of the above measurements I'd be surprised if the Maxim's voicing wasn't also an important factor in the BBC's decision not to use it for monitoring purposes, unless it was able to EQ it to level out the upward tilt to obtain a flat response. I actually tried this and the results were surprisingly good, it made the imaging much more convincing.
 
Remember the Maxim will have been designed as a proper ‘bookshelf speaker’ i.e. a speaker designed to be placed on a bookshelf. Despite Jim Rogers making some neat little wall brackets the 149 likes a little space behind it and the wall IME, just 6-10” or so to my ears, and can sound a bit tubby/boomy hard against the wall. Looking at the plots I’d not be surprised if that wasn’t the key difference here.

I’ve never heard a pair but always found them rather interesting as they were so clearly a no-compromise design with huge driver magnets, metal baffles etc. Driver surrounds always look a bit odd though!

PS Probably worth considering baffle-step with true bookshelf speakers as the design intent may well have been to get the correct balance surrounded by books, shelves etc.
 
+1 You beat me to it Tony...

I reckon this is the reason the Leak Mini Sandwich also sounds VERY bass light on stands or on an open shelf with a good foot or more all around.
 
I get a very similar balance from my MS Carnival 1s that I use on my desktop if they are away from the wall.
Move to the wall and they measure flat.
 
Tony L said:
Remember the Maxim will have been designed as a proper ‘bookshelf speaker’ i.e. a speaker designed to be placed on a bookshelf. Despite Jim Rogers making some neat little wall brackets the 149 likes a little space behind it and the wall IME, just 6-10” or so to my ears, and can sound a bit tubby/boomy hard against the wall. Looking at the plots I’d not be surprised if that wasn’t the key difference here.

I’ve never heard a pair but always found them rather interesting as they were so clearly a no-compromise design with huge driver magnets, metal baffles etc. Driver surrounds always look a bit odd though!

PS Probably worth considering baffle-step with true bookshelf speakers as the design intent may well have been to get the correct balance surrounded by books, shelves etc.
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Arkless Electronics said:
+1 You beat me to it Tony...

I reckon this is the reason the Leak Mini Sandwich also sounds VERY bass light on stands or on an open shelf with a good foot or more all around.
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The Maxim is indeed extremely well-built, in fact inch-for-inch it is the heaviest and most inert mini-monitor I've encountered. Do the knuckle-test on them and you'll likely break your fingers before you hear any ring from the enclosures!

The driver surrounds do look odd, but they are actually pretty robust and stand the test of time very well (they date from 1965). I have seen the odd one on eBay with a split in it, presumably due to over-excursion.

Would bookshelf or tight-to-wall mounting restore frequencies all the way up to 500Hz? I assumed that this mainly affected the lower frequencies. Pity I don't still have a pair to put the theory to the test...
 
ToTo Man said:
Would bookshelf or tight-to-wall mounting restore frequencies all the way up to 500Hz? I assumed that this mainly affected the lower frequencies. Pity I don't still have a pair to put the theory to the test...
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That, along with altering the baffle-step with surrounding books, would likely help. It is also worth noting that dating from 1965 they are very much ‘valve-era’ designs, so will likely sound hopelessly dry and lean with highly-damped modern solid state amps. I find this to be the case with many vintage speakers (Tannoys, Klipsch, Quad 57s etc etc), they only gain that naturalness, ease and body when partnered with kit similar to which they were obviously originally voiced with.
 
My recollection may be unreliable, but I think the Maxims were to be accompanies by a transistor amp based on the design that Leak nicked from its inventors. How well the combination worked, though, I have no idea.
 
Jim Audiomisc said:
My recollection may be unreliable, but I think the Maxims were to be accompanies by a transistor amp based on the design that Leak nicked from its inventors. How well the combination worked, though, I have no idea.
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I’d forgotten about that! The Goodmans Maxamp 30. There was a matching tuner too and the whole lot could be lined up in a row like some kind of ‘60s pre-ghetto blaster. I don’t think the amp ever had much respect, the first wave of transistor amps were not well liked at all and certainly failed to match up to the beautiful valve amps of the era. The Sugden A21 and Quad 303 being the first UK solid state amps with any lasting credibility, and they both arrived a few years later towards the end of the decade.

PS I know nothing of the connection to Leak you speak of, nor the accusation that Leak had “nicked” any designs. Care to elaborate?
 
Martyn Miles said:
I believe Harold Leak copied the Tobey - Dinsdale amplifier for his first transistor amp.
It’s on the Internet somewhere...
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I read that Harold Leak threatened to destroy the designers with counter claims and legal costs if they stood up to him.
 
What intrigues me is that these Goodman's mini monitors use metal as the baffle material. I recently acquired some Radford monitors (not mini at all) which are a three way design using Goddman's drivers. The baffle for the two smaller units, which is in a separated section of the cabinet, also use metal as a baffle material and I had not come across that before. Was this quite common back in the 60's or was it a technique favoured by some manufactures/designers?
 
Nagraboy said:
I read that Harold Leak threatened to destroy the designers with counter claims and legal costs if they stood up to him.
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You are correct.
The Tobey-Dinsdale design Harold Leak stole was used by Truvox as well a Goodmans.
Not a very nice character was Mr. H Leak...
 
Yes, the letter makes the episode clear. FWIW I met Dinsdale in the 1980s when I gave a talk on the new-fangled 'Audio CD' at Dundee Uni. He asked some questions from the audience, but although he remained keen on LP they were polite, not dismissive. Good engineer and decent bloke.
 
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