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SPL - Sound pressure level


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can anyone do this in real terms.....

 

looking at all these new speakers they all list SPL which must be important

 

some list it as 14 db

 

others go for a number (eg 97 (1w - 1m)

 

is that the same measurement ?

in real terms what is the difference between a 97 and a 124 (if same)

 

 

help please!!!!!!!?????

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Will it go loud.....

 

SPL is a way of telling how loud somthing will go....

 

Typical values are 85-89 dB for bookshelf speakers, 87 to 92 dB for floorstanding models, with high efficiency pro and disco speakers in the 93 to 100+ dB range

 

Baiscly the bigger the number the loud it will go....

 

all you need to know is on this link

 

Speaker SPL - How much power do you need?

 

enjoy

 

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The sensitivity of a speaker is given as 1w @ 1m (which is calculated as 1m distance doesn't necessarily give accurate results when measuring. Working on the basis that 3dbA increase takes twice as much input power you can work out the rough estimate of how loud you can go.

 

So a 99db/1w/1m speaker would give:

 

1w - 99db

2w - 102

4 - 105

8 - 108

16 - 111

32 - 114

64 - 117

128 - 120

256 - 123

512 - 125

1024 - 128

2048 - 131

 

So, the reason why people seek the best sensitivity is because ultimately it'll decide how loud you can go. A 106db/1w/1m bass-horn will always have the ability to play louder than a 100db/1w/1m reflex box (+6db for any given input power). In fact, in many cases it'll just be unachievable regardless of how much power you can put in.

 

Of course this is very simplistic, there has been no regard for power compression or heat losses and at the upper end of the scale these factors play a large role in determining the max SPL a speaker will produce.

 

unfortunately these are often calculated using different methods (white noise bursts at 1khz, swept sine waves, etc) and unless they state which method was used you'll only ever be comparing apples with oranges.

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Just to add to what Marky said (sorry, didn't read the link):

 

The numbers that Marky gives are efficiency figures and are normally an indication of how loud a speaker will be 1 meter away for 1 watt of input power. (Obviously the speaker will get louder than this figure as you put more watts in, or sound quieter as you move further away.) These are a good figure to use for comparison.

 

You may also come across maximum SLP (Sound Pressure Level) type figures. These are normally figures of well over 120dB and are the loudest that it is possible to get the speaker to go when it is distorting like f:cense:k and smoke is coming out of it. This figure doesn't mean much in the real world.

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yep sadly most of the cheeper speakers with large SPL numbers just sound rubbish when pushing these levels....

 

so a large SPL is not the be all and end all.......

 

if you want to be able to tell what the DJ is playing and not just make people deaf you need a combination of good speakers good amps and also good wiring, its funny how many people over look the quality of the cable's they use and it makes so much diference to the final sound you will be suprised..

 

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Thanks Marky..... i am thinking that it helps......

 

so to clarify

 

a speaker with a 96 SPL (in the 1w-1m) range, when driven at 300w would have an SPL of approx 121 (given what that web page says).....

 

this is not as good as 124 SPL for continuous usage (as the SRM450's claim) but not so shoddy.........

 

think i understand http://www.dj-forum.co.uk/html//emoticons/sterb188.gif

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dont forget all these numbers are based on an empty room....

 

having the best sounding speakers in the known universe wont help you if they are hidden behind 200 screaming kids...

 

placement of speakers and general common sence will turn an ok disco into a top class act...

 

speakers like the 450's should be on stands at arround head height or mabe a little more so that people at the back of a dance floor can hear it too

 

if you ran the 450's on the floor then you would find your self turning them up more to try and compensate......

 

 

 

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Also a lot of speaker companies measure the SPL in a "Half-Space" environment, which will boost the figures they publish.

 

For example Turbosound and HK Audio use Half Space measurments for giving their Specifications, compared to other makes that do not use Half Space you can start to see that even some supposedly high end speakers are not as high end as they first appear.

 

Also some quote Peak SPL running the speaker at Peak Power, others quote Peak SPL running at full RMS power.

 

Always check the small print to ensure the figures given are comaparable to others.

 

Same for AMp outputs, some use old Japanese testing standards which are far outdated compared to the reformed Jap standards, this is simply to give the impression their amps are more powerful, but at the end of the day they are not cheating you, it;s up to you to know the differences of the tests they perform.

 

 

 

I think in this day and age there should be ONE standard for testing audio outputs, and all companies should be forced to stick to it and quote all test figures accordingly... at least everyone would know what their buying.

 

 

Regards,

 

Phil Hulton

HeadlineDJ

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QUOTE
I think in this day and age there should be ONE standard for testing audio outputs, and all companies should be forced to stick to it and quote all test figures accordingly... at least everyone would know what their buying.

 

Agreed http://www.dj-forum.co.uk/html//emoticons/thumbup.gif - it's a minefield out there http://www.dj-forum.co.uk/html//emoticons/headphone.gif

 

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QUOTE
this is simply to give the impression their amps are more powerful, but at the end of the day they are not cheating you, it;s up to you to know the differences of the tests they perform.

 

...but its also up to the manufacturers to tell us how they conducted their tests in the first place and the methods and environment they used.

 

How many sub manufacturers do you know that don't state whether the frequency range their speaker will play to is the f3, f6 or f10 point? It's far too many imo.

 

How many people really believe that they'll get useable 40hz performance from their 15" + 1.5" horn mid/tops box because they are advertised as being 20-20,000hz freq response?

 

Half space is an entirely reasonable and real-world measurement to use as it will generally be the worst-case that a speaker will be used in. Unless you're skydiving with it of course.....

 

Lots of basshorn manufacturers fail to mention that optimum performance will only be achieved when they're used in multiples of 2 or 4 in a stack... and of course everyone knows that an 18" driver will give better bass performance than a 12" one, right? right.... :unsure:

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QUOTE
and of course everyone knows that an 18" driver will give better bass performance than a 12" one

 

And this is another minefield.... Just cos you have 1 18" bass, or 4 12" bass in a cabinet doesnt mean its louder.

 

Bass frequencies on a larger diameter cone go lower, because the cone doesn't return to the center position as fast as a smaller cone. This is why an 18" cone has a deep thump, but a 12" cone is a nice tight bass.

 

For a standard sized venue, a 15" or possibly a 12" bass driver is ok. An 18" would be too bassy.

 

If your outside in a field then a 18" driver will have a better SPL than a smaller driver.

 

It is a case of trying the speakers in diffent situations an see what sounds and works best for you.

 

I use a 15" driver each side on my small & Medium rigs, But i use a pair of 18" cabinets on my Big rig, and the Nightclub and outdoor setups use at least 2x 18" drivers for sub bass, a pair of 2x12" drivers for bass, then various horns and cones for the top and mid.

 

By using 18" cones for sub bass, and 12" for bass i get a nice tight punchy bass, with the deep thump you can actually feel.

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Hope this helps... http://www.dj-forum.co.uk/html//emoticons/thumbup.gif

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I have across my 4 cabs a total of 8 15" drivers.

 

The subs are dual 15"'s so this helps as it couples the drivers and adds a 3db boost to the efficiency of the drivers if thery were merely single driver cabs.

 

Also I'd prefer to use a dual 15" over a single 18" as the bass is much tighter and as stated the coupling helps increase efficiency.

 

Positioning is also rather important especially for subs with them bein omni-directional.

Stages and subs can give some very odd effects, and also is one of the causes why many bands and some DJs blow subs, as they can cancel out and then the person drives them harder to get more ouput and thus in turn cancels out even more so, result, they end up blowing the drivers or blowing their amps.

 

This is fairly uncommon due to the actual outputs used by many people, but in larger installs and setups it can be a very real problem.

 

Regards,

 

Phil Hulton

HeadlineDJ

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Actually the '18" better than 12"' comment was meant with some irony (damn you, lack of irony smilie http://www.dj-forum.co.uk/html//emoticons/tongue.gif )

 

One of the best performing subs is actually the LAB sub which runs on 2 x 12" drivers on a big horn. Unfortunately they were designed to be used in blocks of 4 (needing 2kw per cab) so a bit unwieldy for the kiddies disco http://www.dj-forum.co.uk/html//emoticons/rolleyes.gif

 

Horns do seem to have a directional element to them, you can definately tell when you are off axis with them.

 

As to the tightness of a 15" over an 18", much of that will be down to the nature of the voice coil as much as cone size. It is possible to make an 18" tighter and punchier than a 15" but as most 18 applications are bass reflex and bandpass boxes, the 'mush motors' (higher cone weight, smaller diameter magnet/VC assembly, boomier sound - sometimes described as 'warmer') tend to be more prolific.

 

The Precision Devices 1850 and Void V18-1000 are examples of 18" drivers that have a good tightness to them and are more suited to a horn loading than BR or BP. Unfortunately they like about 2000wrms @ 8ohms each to really make them work!!

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But the damping factor of the amp is really only an indication of how well the amplifier can control the movement of the cone. Most modern day amps have more than adequately high damping factors, and even though this reduces as you get a lower impedance, even at 2ohms (or lower if you're lucky enought o own Crown Macros or similar) they have more than enough for PA requirements. Damping factor is one of the audiophiles most over-used and under-understood terms.

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Like i said, PD are one of if not the best cone manufacturer in the world (personal opinion http://www.dj-forum.co.uk/html//emoticons/tongue.gif ) and there BRITISH !!!

 

Check this out Prestige Series - PD2450

 

It is a 24" 1000W @ 8 Ohm driver!!!! http://www.dj-forum.co.uk/html//emoticons/biggrin.gif

 

Not really practical for us lot, but WOW factor 10/10 http://www.dj-forum.co.uk/html//emoticons/tongue.gif

 

The PD 1850 is a lurvly speaker... i have 2 in my Turbosound bins.

 

but the void 18 is no longer made... http://www.dj-forum.co.uk/html//emoticons/014.gif

 

I have been installing PD for a while now and i must admit... they are much better sounding and made than most other manufacturers. I only use the Eminence stuff for budget, and replacing blown drivers in older kit - unless the customer wants to pay for the quality of a Precision Device in their speaker (and lets face it, most DJ's dont see the point of paying the extra £££ over something they know i.e. Eminence.

 

PD Rulez !!! http://www.dj-forum.co.uk/html//emoticons/thumbup.gif http://www.dj-forum.co.uk/html//emoticons/cool.gif

The only UK number 1 record to contain in its lyrics the title of the song which knocked it off number 1 was... Bohemian Rhapsody by Queen (lyric: "Mamma Mia")!

 

The Forums Computer Nutter and expert!

 

 

Discos, Lighting and Sound Reinforcement in and around

Oxfordshire, Wiltshire, Gloustershire and Buckinghamshire etc...

 

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The 2450 was (iirc) made for a marketing promotion and to be fair is not really very practical due to high moving mass. A 1850 should outperform it in most applications but as you say the wow factor is good http://www.dj-forum.co.uk/html//emoticons/biggrin.gif Have you ever been to The Fridge in Brixton? they've got some old (I think) EV 30" or 32" drivers in a reflex cab surrounded by metal caging. Look fantastic but soundwise.... http://www.dj-forum.co.uk/html//emoticons/sad.gif

 

The Void 18 is still alive and kicking as far as i'm aware - a lot of people I know are still using them as they're slightly easier to drive for the amp than the PD and abit cheaper. PM me if you'd like to know where to get 'em from. I use PD, Beyma and P-audio drivers and although they're not so well known or established the p-audio's are superb. They also have a very good neo magnet range which work very well (I use them in my mids) and you save 5-6kg a driver.

 

They also do a big 18 to rival the void and PD and is fairly interchangeable with the regular loadings of the V18 and 1850.

 

 

Actually on the subject of Void, have you seen their Basys system? 2 15" bins, 2 mid tops plus a Void 3 way amp to drive the lot. Around 1.5k all together and said to sound beautiful. I think they go for about £1500 all in which is a bargain, a one-stop-shop and you don't have to worry about sorting other pieces. Only downer is the cabs are mdf rather than birch ply but i could live with it....

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