"Running in" speakers

[ef37a]

Ok yes! I know, done to death in the past but some might like to know that I have modified my position on this (possibly!)

My Tannoy 5As were on wall brackets for a good 9 years in a room 12 by 12 by 8.5 feet. Carpet on boards and a couple of HM absorbers and some pyramid foam at the sides. They were angled in and about 900mm ctr to ctr.

The sound quality was, IMHO very satisfactory and the bass response 'there' but hardly inspiring. The speaker now sit on stands about 1.3m apart and I listen about 1.8m from them. The room is 14 feet by 10 by 8.5 (sorry for the mix of measures!) and they fire down the long axis.

I am now very surprised at the increased level and extension of the bass response. Could it be that all those years son was using the speakers, vastly more then I, that the cone suspensions have 'freed up' and now deliver another half octave? As the monitors are now used for all my sound sources including telly I am constantly surprised by the amount of LF 'stuff' going on? Some of it seems totally unnecessary and of course, totally inaudible to the average FSTV viewer.

Dave.

[Tim Gillett]

Dave, are you saying the change happened after the change in speaker and seating positions... or not?

[Hugh Robjohns]

Ok yes! I know, done to death in the past but some might like to know that I have modified my position on this (possibly!)

I'm pleased to hear that, Dave, but I fear your observation has nothing to do with 'running in' which is an effect occurring over a matter of hours or days, at most, certainly not years!

My Tannoy 5As were on wall brackets for a good 9 years in a room 12 by 12 by 8.5 feet..... The speaker now sit on stands (...in a...) room... 14 feet by 10 by 8.5.

Your first room was a squashed cube, and I'll bet the listening position was close to the centre of the room. This is the known worst case scenario where the inevitable standing waves tend to align and create a wide LF cancellation 'bass hole' in the centre of the room.

Your new room's dimensions are a lot more favourable, as is your listening position within the room. Standing waves will be better distributed and effectively weaker, resulting in a more even LF response at the listening position.

Could it be that all those years son was using the speakers, vastly more then I, that the cone suspensions have 'freed up' and now deliver another half octave?

I'd love to say yes, just to change your view on speaker running-in, but the reality is that you're just experiencing classic room mode interactions.

I am constantly surprised by the amount of LF 'stuff' going on? Some of it seems totally unnecessary and of course, totally inaudible to the average FSTV viewer.

There are a lot of rumbly things on TV... some very effective and appropriate, and some frustratingly not — like terrible voice-over mic popping on news programmes. Grrrr.

[ef37a]

Ok yes! I know, done to death in the past but some might like to know that I have modified my position on this (possibly!)

I'm pleased to hear that, Dave, but I fear your observation has nothing to do with 'running in' which is an effect occurring over a matter of hours or days, at most, certainly not years!

My Tannoy 5As were on wall brackets for a good 9 years in a room 12 by 12 by 8.5 feet..... The speaker now sit on stands (...in a...) room... 14 feet by 10 by 8.5.

Your first room was a squashed cube, and I'll bet the listening position was close to the centre of the room. This is the known worst case scenario where the inevitable standing waves tend to align and create a wide LF cancellation 'bass hole' in the centre of the room.

Your new room's dimensions are a lot more favourable, as is your listening position within the room. Standing waves will be better distributed and effectively weaker, resulting in a more even LF response at the listening position.

Could it be that all those years son was using the speakers, vastly more then I, that the cone suspensions have 'freed up' and now deliver another half octave?

I'd love to say yes, just to change your view on speaker running-in, but the reality is that you're just experiencing classic room mode interactions.

I am constantly surprised by the amount of LF 'stuff' going on? Some of it seems totally unnecessary and of course, totally inaudible to the average FSTV viewer.

There are a lot of rumbly things on TV... some very effective and appropriate, and some frustratingly not — like terrible voice-over mic popping on news programmes. Grrrr.

Yes Hugh, almost all the result of a bigger better room. I just wondered if the woofer resonance had dropped a bit over the years, and no, I have not really changed my mind on running in and even if that has happened a bit in my case it has taken a bloody long time to show itself!

Dave.

[Hugh Robjohns]

I just wondered if the woofer resonance had dropped a bit over the years...

No. If that was going to happen — and it does in some cases, honest — it would happen during the first few hours /days. It follows the familiar 'bathtub curve' of a brisk initial settling down, followed by a decade or two of stable performance, and then (often) surround failure and destruction.

In your case, it's just room acoustics 101.

[ef37a]

I just wondered if the woofer resonance had dropped a bit over the years...

No. If that was going to happen — and it does in some cases, honest — it would happen during the first few hours /days. It follows the familiar 'bathtub curve' of a brisk initial settling down, followed by a decade or two of stable performance, and then (often) surround failure and destruction.

In your case, it's just room acoustics 101.

Yes Hugh I did know that some speaker surrounds and spiders 'free up' after a bit of use. You may not be old enough to know the works of G A Briggs? (Wharfedale) but he suggests in his book on speakers and cabs that the speaker be connected to a low voltage 50Hz source for a few hours. But that was in about 1965. Surely speaker materials have improved since then?

Dave.

[Hugh Robjohns]

Ya cannae change the laws of physics Captain, or material science come to that! Yes, there are better glues, now, but the principles remain the same.

Possibly what has changed in some cases is the tolerances involved in matching drivers to cabinets in some designs... which is where the running-in reveals itself.

[Arpangel]

I’m thinking this "running in" thing, is just a psychological acceptance of a speaker's sound, and nothing to do with the actual speaker, and most people will already have speakers that they have got used to over time, and it’s this "adjustment" period that people find difficult, even though the new speakers may be considered "better"

[ef37a]

I’m thinking this "running in" thing, is just a psychological acceptance of a speaker's sound, and nothing to do with the actual speaker, and most people will already have speakers that they have got used to over time, and it’s this "adjustment" period that people find difficult, even though the new speakers may be considered "better"

I tend to agree Tony and since you have 'kept the thread alive' so to speak I would like to counter the reference to the "bath tub curve".
I am no statistician but I am sure that "failure over time" data model refers to a large collection of things, usually tested at their design limits (temp, volts, dissipation) such as ICs. Many will fail in the first few hours. Most will survive days or months and then a big jump in failures.
The process does not apply to bulk materials as far as I know?

There may be a drop in cone resonance in the woofer over time but that should only affect the bottom octave and in any case, IF I am paying £3k for a pair of monitors I expect the maker to free the suspensions up before I buy them! Hiss easy to do!

Dave.

[Hugh Robjohns]

Whatever... it makes no real difference either way. Speakers become 'run-in' one way or another. To most end users it doesn't matter at all.

It matters to me as a reviewer only because of the short period of time I have with some products, so it's something I'm aware of and deal with if it occurs. And I know it has and does, occasionally.

If you choose not to accept my comments and explanations, thats fine. Neither of us will be affected in any practical way by it.

Other popular but irrelevant things to argue about on Internet forums include: The Earth is flat. The Americans never landed on the moon. A dinosaur lives in Loch Ness....

... believe whatever your own (limited) experience implies and whatever you're comfortable with.

[James Perrett]

I am no statistician but I am sure that "failure over time" data model refers to a large collection of things, usually tested at their design limits (temp, volts, dissipation) such as ICs. Many will fail in the first few hours. Most will survive days or months and then a big jump in failures.

I'm surprised you say this Dave - especially as you were a service engineer in the early days of colour TV. In the shop where I worked we always assumed that a newly delivered TV would be faulty so it went straight to the service department (called Bert) who checked it and usually fine tuned the convergence and other adjustments. Probably 30% were properly faulty which ties in with the first section of the bathtub curve.

The only ones that were rarely faulty were the Japanese brands that we sold.

So the bathtub curve can be applied to both components and systems which are running under normal operating conditions.

[Drew Stephenson]

For anything mechanical you will have stuff that wears out causing end-of-life failure. Things like speaker cones are also generally glued together and those glues harden and fail over time. Rubber surrounds perish. Plastics exposed to sunlight disintegrate...
There's loads of evidence to support the bathtub model applying to a whole range of goods.

[ef37a]

No James, nothing to do with "bathtubs"!

I was in at the very first CTVs (PAL) broadcasts and if you took 50 TV sets off the lorry and just switched them on in the shop (BBC2 only of course!) ALL of them would have purity and convergence errors.
Nothing to do with "reliability" the errors were caused by the TVs swinging through the earth's magnetic field, iron bridges, OH power lines and all other magnetic sources. In fact it would have been statistically virtually impossible to find a set NOT out of whack! Of course once we had the tellies adjusted in the workshop it had to be done all over again at the customer's home and if wifey decided to change the room around..all had to be done again!

Yes, one or two TVs would not work but in truth we could never get enough at any one time to get much of an idea of failure rates (you had to put your name down and a wedge to get a CTV back then!)

By the time the Japanese had entered the UK CTV market purity and convergence problems had pretty much been licked. Philips, Ferguson, Grundig, Sony all worked pretty well straight out of the box and they had now developed 110dgr CRTs and even a 26" TV was a one (strong) man job.

Hugh, we all have "limited knowledge" no need for the dig.

Drew, such failures as you describe would not happen to a new product and since those that occurred over (a long) time were caused by very variable external effects the BT curve does not apply IMHO.
Dave.

[Drew Stephenson]

Drew, such failures as you describe would not happen to a new product and since those that occurred over (a long) time were caused by very variable external effects the BT curve does not apply IMHO.
Dave.

I think we're talking at cross purposes somewhere then Dave because to me they are exactly the kind of thing that applies in the final phase of the bathtub curve.
From wikipedia:
The bathtub curve has 3 regions:
The first region has a decreasing failure rate due to early failures.
The middle region is a constant failure rate due to random failures.
The last region is an increasing failure rate due to wear-out failures.

[Hugh Robjohns]

Hugh, we all have "limited knowledge" no need for the dig.

Not a dig, and you misunderstood my point.

I've had hundreds of speakers here, both to review and for my own use, over the last 30 years or so. That's a lot of experience of listening to brand new speakers, in direct comparison to known references. In comparison, your experience is limited... with all due respect. Thats all I meant.

Under these circumstances, changes of sound character in the early stages of use, if present, are very obvious and can't be attributed to 'getting used to new speakers'.

Perhaps the bathtub analogy was a poor choice and has confused you. I wasn't talking about the Mean Time Between Failure — the usual bathtub association and what you're describing with your legacy TVs.

Instead I was trying to allude to the way material characteristics change and settle down during initial use, then remain stable for a long period, before finally degrading and failing at the end of their working life.

If that initial settling change is substantial or critical to the way the thing works, or it takes a longer time than the factory test, you're likely to notice a 'running in' during initial listening.

If it's insignificant, not critical, or quick, you won't!

And now I'm off to no1 daughter's wedding, so signing off....

[ef37a]

Hugh, we all have "limited knowledge" no need for the dig.

Not a dig, and you misunderstood my point.

I've had hundreds of speakers here, both to review and for my own use, over the last 30 years or so. That's a lot of experience of listening to brand new speakers, in direct comparison to known references. In comparison, your experience is limited... with all due respect. Thats all I meant.

Under these circumstances, changes of sound character in the early stages of use, if present, are very obvious and can't be attributed to 'getting used to new speakers'.

Perhaps the bathtub analogy was a poor choice and has confused you. I wasn't talking about the Mean Time Between Failure — the usual bathtub association and what you're describing with your legacy TVs.

Instead I was trying to allude to the way material characteristics change and settle down during initial use, then remain stable for a long period, before finally degrading and failing at the end of their working life.

If that initial settling change is substantial or critical to the way the thing works, or it takes a longer time than the factory test, you're likely to notice a 'running in' during initial listening.

If it's insignificant, not critical, or quick, you won't!

And now I'm off to no1 daughter's wedding, so signing off....

Please give the bride and groom all my best wishes and commiserations to poor old dad's bank account!

My position stands. There has never been any proper investigation into the subject that I know of and Phil Ward has been sceptical in more than one review (he would be the very man to sort this out!)

But, again, even IF speakers "settle in" after a few hours use I still maintain the factory should do it, at least for the ones north of 2-3k!

Just to be clear? The TVs did not suffer a BT failure. They ALL had the same problem and it was well known.

Dave.

[James Perrett]

Just to be clear? The TVs did not suffer a BT failure. They ALL had the same problem and it was well known.

Maybe we had all the dodgy ones then because I definitely remember a significant number of failures of new and nearly new TVs (in addition to the routine adjustments needed).

[ef37a]

Just to be clear? The TVs did not suffer a BT failure. They ALL had the same problem and it was well known.

Maybe we had all the dodgy ones then because I definitely remember a significant number of failures of new and nearly new TVs (in addition to the routine adjustments needed).

What sort of era were you involved in CTVs James? As I said, I was there at the very start. Huge console models mainly 26" Bush and Pye. These were virtually all valve designs , not the most stable devices for line and field sync and amplitude! But I do not recall a significant number of actual faults. You have to remember that this was 'new technology' at least on the domestic scene and built to sell at a reasonable price (but a 26" CTV still cost as much as a very decent second hand car!).

The rot really set in when the rental market exploded and companies like Thorn (Ferguson) wanted cheap and easily repairable TVs. That prompted the design of the first (I think?) all transistor, 'modular' CTV the idea being that the field tech would start his day with a rake of 'modules'. The fly in that ointment was that it was that the "too bloody clever for its own good" chopper PSU caused 85% of faults and they were a B*****D! to fix in the field. Of the next least reliable module was the line output stage and they were no picnic to fix either!

The upshot was that after the third service call the tech was out of modules and had to go back to base to fix them. Day buggered!

A few years later Grundig came out with a semi-modular design but most of their faults were on the PCB Mother board!

One of the most reliable (and best picture) designs was a hybrid ITT/KB which retained valves for line OP, field OP and sound. Later they went all solid state and they were IIRC pretty reliable.

Dave.

[Arpangel]

I see an opportunity to post a rather "I’ll get my coat" joke, at this point, just to cheer things up.

What do you call a dog that lives on a submarine?

a "sub-woofer"

[James Perrett]

What sort of era were you involved in CTVs James?

I was working at the TV shop from 1978-1980 while I was at college. I was mainly a sales assistant but also fixed simple things like kettles. I did Saturdays and school holidays. PIL tubes had just started coming in as I remember it.

The rot really set in when the rental market exploded and companies like Thorn (Ferguson) wanted cheap and easily repairable TVs. That prompted the design of the first (I think?) all transistor, 'modular' CTV the idea being that the field tech would start his day with a rake of 'modules'. The fly in that ointment was that it was that the "too bloody clever for its own good" chopper PSU caused 85% of faults and they were a B*****D! to fix in the field. Of the next least reliable module was the line output stage and they were no picnic to fix either!

The upshot was that after the third service call the tech was out of modules and had to go back to base to fix them. Day buggered!

Yes, I saw quite a few of those modular sets in the workshop and PSU faults seemed common. The cheapest set we sold was a Thorn and it was quite popular. I don't remember many valves by the time I was there although there were still a few in boxes on the shelf.

[Arpangel]

What sort of era were you involved in CTVs James?

I was working at the TV shop from 1978-1980 while I was at college. I was mainly a sales assistant but also fixed simple things like kettles. I did Saturdays and school holidays. PIL tubes had just started coming in as I remember it.

The rot really set in when the rental market exploded and companies like Thorn (Ferguson) wanted cheap and easily repairable TVs. That prompted the design of the first (I think?) all transistor, 'modular' CTV the idea being that the field tech would start his day with a rake of 'modules'. The fly in that ointment was that it was that the "too bloody clever for its own good" chopper PSU caused 85% of faults and they were a B*****D! to fix in the field. Of the next least reliable module was the line output stage and they were no picnic to fix either!

The upshot was that after the third service call the tech was out of modules and had to go back to base to fix them. Day buggered!

Yes, I saw quite a few of those modular sets in the workshop and PSU faults seemed common. The cheapest set we sold was a Thorn and it was quite popular. I don't remember many valves by the time I was there although there were still a few in boxes on the shelf.

I seem to have wives that were part of the TV repair world, my current "partners" dad was a TV repair man, had his own business, in fact, my studio is in his old workshop, my damp basement!
My first wife’s father was a leading light in Radio Rentals, in the 50’s/60’s
I found loads of old valve TV components down in the basement, left over from her fathers days, all interesting stuff.