How loud can I go?

[Ronksley]

How loud can I go?
Normally listen at nine o clock and maybe go up to 11 or even 12 if I want it really loud and the neighbours are out and take 12 as being the limit to avoid damaging speakers
But with AV amps how does this relate as they just display -dbs on a linear scale
I have three AV amps set up with speakers as listed below all just used Stereo, the JPW sub takes the Stereo inputs from amp and then these go onto mini monitors
With the Sony and Teac -50db Yamaha -36db is loud but comfortable and just about neighbour annoying if listening to something loud, most of the time I listen to classical but do listen to some old indie metal or techno stuff every so often
So how do I know what -dbs on these av amps that are sensible loud volumes avoiding possible speaker damage ?

Speakers
Sony STR-DB795 QS
Dennon SC M50
Mordaunt-Short MS20i Pearl

Teac AG H550
JPW Mini Monitors

Yamaha RX-V459 DAB
JPW Sub and Mini Monitors

[walpurgis]

That's like asking 'how long is a piece of string?' You won't know how loud your speakers can go until you blow them up!

You can often (I won't say usually) hear when a speaker is straining, as the bass driver will be reaching the limit of its cone travel and start distorting. But not always. It can just melt its voice coil without warning. Even more likely with mid and treble drivers, you'll get no warning before they pop!

[Pharos]

I wouldn't take any notice of vu type meters on an amplifier.

Maplin sells a decent SPL meter and that is at least useful for in room measurement.

The efficiency of, and maximum power I/P which your speakers specify, are crucial to, and define, the maximum spl you can obtain from them.

Lastly, as an old gitte with damaged hearing, I would advise care in the spls you listen to; 80dB for extended periods can damage hearing.

In about '96 I measured 113dB at 30 feet from my ATC SCM 100As, (this is crazy), and most sound engineers have seriously damaged hearing. I max now at 85dB, and only on peaks, on odd occasions.
Although LF and HF are heard more easily at higher levels, it is much more sensible to improve the equipment to get more penetration into the recording.
Do not risk HF loss and also hyperacusis.

[Ronksley]

Maplin sells a decent SPL meter and that is at least useful for in room measurement.

Yes I should get a SPL meter

Spent my teens going to as many gigs as I could afford, that was in the eighties PAs were loud and guitar amps played so loud feedback was the norm, have slight tinnitus these days and cant here above 14khz. The tinnitus gets worse after I have been turning the stereo up.

Did melt the tweeter magnets of a pair of little Wharfedales I had, only work out what was wrong when I took them apart, the magnets appeared to of been bonded on somehow.

[Yomanze]

It's also crossover dependent. For example, a super-gentle 1st order crossover on the Tweeters is more likely to result in them blowing at higher volumes whereas 2nd, 3rd or 4th order crossovers have steeper slopes (less of the signal reaching them). My Royd RR3s use "modified 1st order" crossovers, and if I played these at party volumes it'd only be a matter of time before the tweeters went, especially as the datasheet recommends that 2nd order crossovers minimum are used.

[Macca]

How 'loud' it sounds depends on how much distortion is present on the signal. So with a really powerful amp and very capable speakers you will deafen yourself before you ever think that you need to be turning it down.

Position of the volume control on the amp is irrelevant. Most amps will be at full out put around half way round in any case. the dB scale on some amps is also meaningless since you don't know what their reference is and even if you did it will differ from one amp to another.

Most domestic home cinema amps will start clipping way before that, so it will sound bad and most people will turn it down at that point anyway. There is always an exception like a pal of mine who would whack his system up into severe distortion for entire listening sessions. He now has tinnitus as a result. But you do have to be pretty daft to do that. It won't happen by accident unless your amps have some very serious reserves of clean power.

[Arkless Electronics]

There is no way of doing it other than using an oscilloscope to check for clipping (or in rare cases some amps have a clipping indicator).

Volume control position is completely irrelevant as is any sort of display on the amp. A SPL meter is also useless for this.

The most common problem is tweeters blowing and this is usually because the amp is not powerful enough for the volumes being used and is clipping. This causes ultrasonic distortion at a power level which will blow the tweeter. At such high frequency all this distortion is fed to solely the tweeter and a tweeter on it's own will usually only handle say 10W even if the speaker says "200W power handling" on the back. This is why a clipping indicator can be useful.

The other speaker blowing issue is the more intuitive "too much power". This can blow any drive unit but bass drivers are the most likely. As pointed out by others above, there is not much you can do beyond common sense and having bit of "mechanical sympathy" by listening out for a speaker under distress, "end stops" being hit by woofer excursion etc...

It is generally far safer to use an amp rated at say 200W into a speaker rated for 50W than to use an amp of 20W into a speaker rated at 200W. Yes this is counter intuitive... but correct.

An add-on clipping indicator is not particularly difficult or expensive to make but the problem is it must be adjusted for a particular amp which needs test gear...

[YNWaN]

It's entirely as AE writes above.

[Pharos]

I disagree with AE about the sound pressure level meter, quite apart from ear protection.

If you have a specification of maximum spl for a speaker, its use can be a guide, but I agree with what as has been said above; if a speaker is able to produce a high spl without distorting, it is hard for the ear to determine.

[petrat]

The most common problem is tweeters blowing ...


You should know, Jez :rofl: Have you got them fixed, sorry, replaced yet?

[Arkless Electronics]

I disagree with AE about the sound pressure level meter, quite apart from ear protection.

If you have a specification of maximum spl for a speaker, its use can be a guide, but I agree with what as has been said above; if a speaker is able to produce a high spl without distorting, it is hard for the ear to determine.

You're wrong to disagree... It would be as much use as a chocolate fire guard.

[Arkless Electronics]

You should know, Jez :rofl: Have you got them fixed, sorry, replaced yet?

Beware of coming back from a live pub gig, half cut, with ears still ringing from said gig, noticing neighbours are out and deciding to REALLY crank it up :doh: :steam:
I've not even looked at them since then... but the 105/3's will live again if there is any way possible, short of spending lots of money, as they are the best speaker I've ever owned by a long way.... in fact I can't think of any speaker at any price that I would replace them with! Your amp will be ready in a day or two BTW.

[Ronksley]

Beware of coming back from a live pub gig, half cut, with ears still ringing from said gig, noticing neighbours are out and deciding to REALLY crank it up :doh: :steam:
I've not even looked at them since then... but the 105/3's will live again if there is any way possible, short of spending lots of money, as they are the best speaker I've ever owned by a long way.... in fact I can't think of any speaker at any price that I would replace them with! Your amp will be ready in a day or two BTW.

I once got back from a gig and somehow programmed a CD I had bought of the band to repeat on tracks 4 and 14 both with lots of bass my old house mate still brings it up to this day I slept till the afternoon and that was twenty years ago ho hum

I feel ok avoiding distortion with records I know but with online sources that are already buggured up with limited bandwidth / compression etc I fine it hard to work out whats going on
think I am going to struggle to blow anything I only live in a two up two down front room is only 12 foot square ? The main problem I have is not being able to hear high frequencies some stuff just feels muddy because of this. I know the Teac could do some damage those poor little JPWs.

[Macca]

David you probably sussed this already but those JPW mini monitors are not up to much. I had some for a while, with sub, not the worst speaker I've owned but in the bottom 5. I've no idea why people all over the forums rate them. Your Mordaunt Shorts are in a different league but they are still a bit small and easy to overload. I've lived in loads of 2 up 2 downs and I know you could get away with something a lot bigger and better in there.

[Minstrel SE]

I just find the sweet spot to compensate for inefficient speakers but I usually listen at very low volumes with the volume control well below 9 o clock.

I have exprienced white noise in here through PA speakers and loud volume is not pleasant to me in the home environment. In my small home I dont need loud volume and unfortunately most of us have neighbours to think about. Those are 12" drivers with a very high efficiency and I can get the feel of some real bass at very low volumes

I think if I didnt have neighbours I could get into the mentality of much louder volumes in a proper music room.

Also I dont want to drive Royds hard as no spare drivers are available. I experiment with sound and can have four speakers running in here on two L/R channels from the same amp....all at very low volume and just finding that sweet spot

There is music that demands a good bit of volume but that tends to be headphone time for me.

Best wishes
Martin

[Ronksley]

I just find the sweet spot to compensate for inefficient speakers but I usually listen at very low volumes with the volume control well below 9 o clock.

I have exprienced white noise in here through PA speakers and loud volume is not pleasant to me in the home environment. In my small home I dont need loud volume and unfortunately most of us have neighbours to think about. Those are 12" drivers with a very high efficiency and I can get the feel of some real bass at very low volumes

I think if I didnt have neighbours I could get into the mentality of much louder volumes in a proper music room.

Also I dont want to drive Royds hard as no spare drivers are available. I experiment with sound and can have four speakers running in here on two L/R channels from the same amp....all at very low volume and just finding that sweet spot

There is music that demands good bit of volume but that tends to be headphone time for me.

Best wishes
Martin

get rid of your neighbours by moving of course headphose are not an option to me

and reply to Macca I have better speaker in my bedroom Castle Wariscks Raurks Epilogues
I have no one in next door so can crank it up
I really rate the JPWs cheap and cheerful

[Macca]

get rid of your neighbours by moving of course headphose are not an option to me

and reply to Macca I have better speaker in my bedroom Castle Wariscks Raurks Epilogues
I have no one in next door so can crank it up
I really rate the JPWs cheap and cheerful

Epilogues are a top speaker. We cam disagree about the JPW :)

[Pharos]

"You're wrong to disagree... It would be as much use as a chocolate fire guard. "

My strategy or disagreeing?

Have you heard of the concepts of arrogance, and humility?

[Simon75]

Interesting reading about people's experience of listening to music at loud volumes. I'm 41 and I've more or less stopped listening to music through headphones due to concerns that it was causing damage to my hearing, this despite the fact that I only every used them at home and what I considered to be low to medium volume levels for limited periods maybe a few times a week. Currently I am listening to music through a pair of tannoy precision 6.1 standmounts, if I listen to maybe 40 minutes at 9oclock or above I would experience some discomfort later in the day. At the moment I am learning to appriecate listening to music at a volume I would consider sub optimal in the past. I would love to have a set of floor standers but do wonder how much use the average listener gets from them, that's assuming that like me most people live in built up areas with neighbours in close proximity.

[Pharos]

The trouble with headphones is that they can produce high spls without any indication that they are doing so by distorting, and the young with their 'phones are at serious risk currently because of this.

Tinnitus and hyperacusis becon.

[RothwellAudio]

of course headphose are not an option to me

Why "of course"?

[Arkless Electronics]

"You're wrong to disagree... It would be as much use as a chocolate fire guard. "

My strategy or disagreeing?

Have you heard of the concepts of arrogance, and humility?

I'm aware of the concepts and consider them hugely over rated actually. Have you heard of the concept of knowing what you are talking about before posting myth as fact?

[Barry]

I'm aware of the concepts and consider them hugely over rated actually. Have you heard of the concept of knowing what you are talking about before posting myth as fact?

Not a very constructive remark Jez.

I do however agree that the use of sound level meters, and the interpretation of the measurements made, is not for the noviciate.

I have 'played' around with a Maplin SPL meter - I found it of doubtful accuracy and limited to frequencies < 5kHz. But for what its worth when set up 4.2m away from the centre line between my speakers (Quad 57s) and at a height of 0.75m (level with my ears when sat in my chair), I obtained the following figures: -

Speech at normal conversation level: 55 - 60dBA

Late night listening (= '6' volume setting on a Quad 44): 60-70dBA

"Belting it out" (= '10' volume setting on Quad 44): 70-80dBA

"Shaking the floorboards" (= '14' volume setting) ~ 85-90dBA

[Arkless Electronics]

Not a very constructive remark Jez.

I do however agree that the use of sound level meters, and the interpretation of the measurements made, is not for the noviciate.

I have 'played' around with a Maplin SPL meter - I found it of doubtful accuracy and limited to frequencies < 5kHz. But for what its worth when set up 4.2m away from the centre line between my speakers (Quad 57s) and at a height of 0.75m (level with my ears when sat in my chair), I obtained the following figures: -

Speech at normal conversation level: 55 - 60dBA

Late night listening (= '6' volume setting on a Quad 44): 60-70dBA

"Belting it out" (= '10' volume setting on Quad 44): 70-80dBA

"Shaking the floorboards" (= '14' volume setting) ~ 85-90dBA

Add in the directionality versus frequency, power handling versus frequency, power handling versus time, the inverse square law applying to sound from a point source (or approximating a point source) and the differing reflectivity/absorption of rooms and I think we could say that gauging safe power handling for a speaker using a SPL meter would be pretty useless...

The best protection I know of is that once used by KEF in their "S-Stop" technique. I believe B&W had something similar....

[Macca]

Well I like to play at a decent volume and I've never blown or damaged a speaker in 30 odd years so it can't be that easy to do.

[Barry]

Well I like to play at a decent volume and I've never blown or damaged a speaker in 30 odd years so it can't be that easy to do.

Me neither, but then I've always used an appropriate amp for my speakers: one that has a maximum peak output voltage of < 30V.

[Ronksley]

Why "of course"?
yes why of course ?
Not sure just never consider headphones as an option and assume that much use would further damage my hearing
I just like speakers and the way noise comes at you and washes over you I think listening with the whole body is better than just using ears

[Simon75]

I certainly enjoy listening to music on headphones however I do ultimately think it's best enjoyed from a
good set of speakers. Isn't music itself performed aloud?

[Pharos]

"I'm aware of the concepts and consider them hugely over rated actually. Have you heard of the concept of knowing what you are talking about before posting myth as fact? "
Yes AE, the first part is fairly evident now I think about it.

I stand by what I said, and I do analyse my thought processes not only in electronics, but in all else.

With a manufacturer's specified maximum spl O/P for a speaker, an spl meter is of use in knowing whether or not one is approaching the maximum limit of I/P power to a speaker.

I have formed the impression that you overate yourself and also are rude.

[walpurgis]

Dennis. I'd suggest you and Jez 'debate' this no further. Thanks.

[RothwellAudio]

It may be useful to consider the failure mechanisms for loudspeakers.
Firstly, a voice coil could get so hot that the wire literally melts, like a fuse. The wire isn't very thick, so melting it isn't impossible. The heat tends to build fairly gradually and dense music with lots of sustained bass is likely to have a strong heating effect on woofers. Tweeters have thinner wire than woofers but generally don't have to cope with a lot of heat. But an amp could go into ultrasonic oscillation or be fed from a pre-amp generating ultrasonic frequencies which would fry a tweeter fairly quickly and you wouldn't even know (because it's ultrasonic) until it's too late.
Secondly, the voice coil could get very hot but not hot enough to melt the wire. Instead the voice coil former and the glue holding it together get so hot that the voice coil looses its shape doesn't move backwards and forwards cleanly in the gap it's meant to fit, and it scrapes or even gets stuck.

A second type of failure mechanism is due to transients forcing the cone to move - or attempt to move - too far. In this case wires can be snapped rather than melted.

Anyway, I don't think there's a reliable way to measure or calculate anything that will tell you which spot on the volume control's travel is the safe upper limit. My advice if you like your music loud is to use high efficiency speakers, maybe 96dB sensitivity or more. Don't put a pair of BBC LS3/5As on the end of a 500W amp and wind the wick up as far as it will go :doh:

[Simon_LDT]

It's a bit of common sense though... surely? (without getting technical of course)

I know odd things can happen but if one uses a decent powerful enough amp/s for the speakers and listens within a sensible level in regards to it's size then there shouldn't be a problem. Like Andrew mentioned above with the BBC 3/5a's.

Also, it shouldn't matter about db settings on amps as they will all be different anyway. Always trust the ear first and foremost, if it sounds too loud - it probably is! My current (and forthcoming) pre don't have any level settings or fascia markings, other than an indicator on the dial. I know where my preferred listening level is for all formats, be it CD, LP and whether it is a modern compressed mess with DR6 or an older DR13.

I know I like to crank mine when the neighbours are out and I know it's loud but not too loud that it causes fatigue or ringing in the ears (if ringing happens, it is blatantly too loud imo).

[Arkless Electronics]

The problem is the logarithmic nature of human hearing... this is why it can be easier than one may think to blow drive units. 1Watt is actually pretty loud but if you want it to sound twice as loud then you need 10W. You can see where this is going... The 10W sounds good and rockin out loud but you think "just a bit louder"... and what sounds to you just that bit louder has now gone from 10W to 70W...

[Arkless Electronics]

"I'm aware of the concepts and consider them hugely over rated actually. Have you heard of the concept of knowing what you are talking about before posting myth as fact? "
Yes AE, the first part is fairly evident now I think about it.

I stand by what I said, and I do analyse my thought processes not only in electronics, but in all else.

With a manufacturer's specified maximum spl O/P for a speaker, an spl meter is of use in knowing whether or not one is approaching the maximum limit of I/P power to a speaker.

I have formed the impression that you overate yourself and also are rude.

Try analysing it and coming up with the correct conclusions then... I've explained in a previous post just why one very definitely cannot use a SPL meter to determine max safe volume. As to the personal insults well you know what you can do pal. I shall add you to my ignore list as I'm sick of reading utter rubbish presented as "insightful" (ha) fact.

[Simon_LDT]

The problem is the logarithmic nature of human hearing... this is why it can be easier than one may think to blow drive units. 1Watt is actually pretty loud but if you want it to sound twice as loud then you need 10W. You can see where this is going... The 10W sounds good and rockin out loud but you think "just a bit louder"... and what sounds to you just that bit louder has now gone from 10W to 70W...

True, didn't think about it like that (just turned mine down a notch haha) :D

[Macca]

Do manufacturers ever specify a 'maximum spl'? I've never seen this. Only maximum power handling. Which manufacturers give max spl figures? And do they specify at what distance? Otherwise it is pretty meaningless.

[anthonyTD]

Most reputable speaker drive unit manufacturer used to state Max SPL figures as well as Max power handling, one could easily establish then for eg, if a drive unit had a maximum SPL of say 114 db, and a sensitivity of 96 db per watt, per mtr, then well,,,I am sure most will understand where I am coming from on this...:eyebrows:
Distortion, and paticularly certain aspects of distortion can be a tel tale sign that something is too loud, however, when you have an amp that has lots of clean power, then it can be quite easy to reach SPL levels not only damaging to the drive unit, but to long term human hearing too!
Do manufacturers ever specify a 'maximum spl'? I've never seen this. Only maximum power handling. Which manufacturers give max spl figures? And do they specify at what distance? Otherwise it is pretty meaningless.

[Macca]

So this was something that used to happen back in the dim and distant then? Can't say I have ever seen drive units, reputable or otherwise, quoted for max spl.

[Arkless Electronics]

Do manufacturers ever specify a 'maximum spl'? I've never seen this. Only maximum power handling. Which manufacturers give max spl figures? And do they specify at what distance? Otherwise it is pretty meaningless.

Some do yes. It is pretty meaningless unless very tightly specified though and even then there would need to be a standard for comparing different speakers.
It can usually be assumed that any such measurement will be taken at 1M, on axis (usually tweeter axis), and in an anechoic chamber. The signal used for testing is critical as well of course! Do you use music? If so what track? Averaged out over what time?
Single frequencies are useless as the practical power handling of a speaker varies massively with frequency. Pink noise is probably the best signal overall.

When one reads that a speaker has a power handling of say 100W it is a very, very loose approximation! Even the woofer will probably handle nowhere near that much if it is a continuous sine wave and the tweeter maybe 10W or so (I'm picking "typical" figures out of the air here so please pedants don't bother looking up the tweeters used in your own speakers to report back that "my tweeters can handle 18.4W" etc). The specified figure can usually be taken as using fairly uncompressed music and not either dub reggae or a penny whistle solo but something that represents "typical music" and spreads the load in a "fair" manner between the drive units. It is also assumed that no clipping occurs of course. Due to thermal time constants it takes a while for a voice coil to heat up and therefore a woofer may take short bursts of say 500W for a second or two even though 30W continuous may blow it. All this is taken into account in giving what is really only a generalised estimate of safe power handling... It is so generalised that one company may give a figure of "100W power handling" for a speaker that another manufacturer would claim only 50W for and a third would claim 150W... It is that "unscientific".
Very often the phrase one sees is "suitable for use with amplifiers up to 100W"... extrapolating from the above, this does not mean the speaker will take a continuous 100W. It means that on this mystery generic typical music track a 100W amp could reach 99.9W (not clipping;)) ON PEAKS, individual kick drum beats, brief crescendos etc, with little chance of harm. It is "cheating" in many respects as it also takes advantage of the peak to mean ratio of the uncompressed music... the output of the amp may well be averaging, over several seconds or a minute, only 10W or so.

Very rarely one may see a more rigorous specification given... usually something like "The speaker is specified as being able handle 100W of unclipped "A" weighted pink noise when applied to the speaker in a regime of 5 seconds on followed by 10 seconds off and for a total test period of 30 minutes at 20C ambient temperature".... something on those lines would be the most scientific specification of power handling I've personally seen. Now try using that to decide just how loud you can safely blast out that AC/DC album... Good luck with that;)

[RothwellAudio]

... and a sensitivity of 96 db per watt, per mtr, then well,,,I am sure most will understand where I am coming from on this...:eyebrows:

Yes, I think so. If you put one watt in and stand 1 metre away you'll hear 96dB. If you put two watts in and stand 1 meter away you'll hear 192dB. If you put two watts in and stand two metres away you'll hear 384dB. The poor buggers standing 3 metres away were vapourised before you had time to turn round :lol:

[Arkless Electronics]

Most reputable speaker drive unit manufacturer used to state Max SPL figures as well as Max power handling, one could easily establish then for eg, if a drive unit had a maximum SPL of say 114 db, and a sensitivity of 96 db per watt, per mtr, then well,,,I am sure most will understand where I am coming from on this...:eyebrows:
Distortion, and paticularly certain aspects of distortion can be a tel tale sign that something is too loud, however, when you have an amp that has lots of clean power, then it can be quite easy to reach SPL levels not only damaging to the drive unit, but to long term human hearing too!

It's far more commonly quoted for single drive units than for speaker systems of course and for obvious reasons! If where you are going here is to agree with phar-off then yes if you have an anechoic chamber, a calibrated measuring mic, a source of a test signal (usually pink noise) and can set the mic up precisely on axis at one Meter then it is possible to do it. Now try it in a normal reflective room, using music as the signal, with a pair of multiway speakers rather than a single drive unit and a typically only +/- 20% accurate SPL meter.... Absolutely no way in a month of Sundays will you get any sort of meaningful measurement whatsoever....

[Pharos]

I feel it relevant to state regarding AE's post 34, that he is not being objective.

He dismisses my posited use of an spl meter, which I still feel will give some approximation.

He has posted that I have insulted him, when in fact I have not, but have merely asked him questions, and stated my impression of his opinion of himself, and his thinking, and without insulting him.

By contrast you will see that he has actually insulted me.

I have always sought intellectual rigour in all I do, and I always ensure that others' feelings are respected, and such behaviour is so violating to that ethos that I think I probably should not post on the forum.

[walpurgis]

Dennis. I may be wrong, but my feeling is that neither you nor Jez have been exactly 'diplomatic' towards each other. Rather than my going into an analysis of what has been said, I'd suggest perhaps your finding other threads to contribute to for the time being might be best. Same applies to Jez if it avoids perpetuating friction.

Only you can decide if you should post on the forum, but there is no reason why you should not that I can see. So please carry on.

[Arkless Electronics]

Dennis. I may be wrong, but my feeling is that neither you nor Jez have been exactly 'diplomatic' towards each other. Rather than my going into an analysis of what has been said, I'd suggest perhaps your finding other threads to contribute to for the time being might be best. Same applies to Jez if it avoids perpetuating friction.

Only you can decide if you should post on the forum, but there is no reason why you should not that I can see. So please carry on.

Didn't read it due to ignore list.
Face to face over a few pints is very different to the nuances carried by mere punctuation and specific choice of words on a forum.... I'm sure Dennis and I would no doubt get on great if we met up at a bake off etc. I guess we're both people who missed our calling with the diplomatic service!
Will remove from ignore list tomorrow.
Don't give up on the best forum around Dennis
Peace and love,
Jez.

[anthonyTD]

:eek::lol:
Yes, I think so. If you put one watt in and stand 1 metre away you'll hear 96dB. If you put two watts in and stand 1 meter away you'll hear 192dB. If you put two watts in and stand two metres away you'll hear 384dB. The poor buggers standing 3 metres away were vapourised before you had time to turn round :lol:

[anthonyTD]

Not realy agreeing or disagreeing with either of you Jez,:scratch: just my usual ramblings!:D
It's far more commonly quoted for single drive units than for speaker systems of course and for obvious reasons!
If where you are going here is to agree with phar-off then yes if you have an anechoic chamber, a calibrated measuring mic, a source of a test signal (usually pink noise) and can set the mic up precisely on axis at one Meter then it is possible to do it. Now try it in a normal reflective room, using music as the signal, with a pair of multiway speakers rather than a single drive unit and a typically only +/- 20% accurate SPL meter.... Absolutely no way in a month of Sundays will you get any sort of meaningful measurement whatsoever....

[walpurgis]

https://www.youtube.com/watch?v=3n3aGIv1JdM

[anthonyTD]

:eek: Great!:lol:
https://www.youtube.com/watch?v=3n3aGIv1JdM

[petrat]

Your amp will be ready in a day or two BTW.

Sorry, Jez, just spotted this ... :thumbsup: