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Are Speaker Manufacturers just "optimistic" ?

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dekra54 View Drop Down
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    Posted: 09 August 2017 at 6:34pm
Good Evening :)

I'm playing with Hornresp/WinISD for the last few weeks and simming numerous drivers and cab types. And from the beginning i wondered how the manufacturers are able to make cabs with those high specs for example a single 15" with 40-330 at 135db max. . Do they have some black magic drivers? Or are the just very optimistic( lyingGeek ) in interpreting the plots ? ( which are seldom availaible ... ).

Greetings from a curious beginer

Dennis


PS.: I know you can you can sim everything to death but its quite fun and you don't have to spend much money ;) )




Edited by dekra54 - 09 August 2017 at 7:10pm
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Pasi Quote  Post ReplyReply Direct Link To This Post Posted: 09 August 2017 at 7:13pm
Everybody lies.

- Dr. House
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Elliot Thompson View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Elliot Thompson Quote  Post ReplyReply Direct Link To This Post Posted: 09 August 2017 at 8:16pm
Lots of manufactures use peak figures in order to catch those solely driven by SPL. There are also processing methods that limits the bandwidth for the sake of more SPL. 

Best Regards,
Elliot Thompson
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Hemisphere Quote  Post ReplyReply Direct Link To This Post Posted: 09 August 2017 at 8:18pm
Which 15" speaker are you talking about? It's not impossible to achieve 135dB at 1 metre with a 15" driver, depending on the loading, but even with a reflex enclosure it's not entirely out of the question.

I just simmed a PD155.N01 in a 100 litre reflex cabinet tuned to 45Hz. With 2800w (rated max input) it's 134dB at 175Hz, but the WinISD sims are a bit lower than the manufacturer's response plots, and at 175Hz it can probably take a bit more than 2800w anyway, so it will definitely achieve 135dB or even more. (Edit: That's with approx -10dB at 40Hz by the way, so it would just barely fit the specification you mentioned)

But that's unusual for a 1x15 reflex.

I find it's best to assume the manufacturer is being 'creatively honest', by which I mean they'll have found a metric by which their claims actually stand up to scrutiny, but the chances that this metric will be intuitive or relevant to the customer are very low

The worst offender being 'peak musical power output' (PMPO), which has been steadily phased out from marketing materials, although LG are regularly releasing systems with approximately this specification attached, which to the best of my understanding means the absolute maximum theoretical instantaneous power flow that could be driven through an amplifier, for any period of time (1ms or whatever) in a controlled test bench environment. In reality the speaker will never drive that much power, and people publishing  PMPO generally don't publish any dB ratings at all.

Beneath that, and much more common, you'll have manufacturers measuring the maximum peak SPL  measurement with white noise or music program. So a design may be 95dB average efficiency across almost the entire range, but have an anomalous spike (as a product of the driver, or the tuning, or both) of 100 or 102dB sensitivity, and it's that sharp spike that gets recorded for the specifications.

There are a few manufacturers with optimistic claims which also publish purported response plots, Mackie for example. You can often see in their published plots that there's a visible peak of 3-5dB, and that's the figure they reference. 


Edited by Hemisphere - 09 August 2017 at 8:30pm
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dekra54 View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote dekra54 Quote  Post ReplyReply Direct Link To This Post Posted: 09 August 2017 at 8:44pm
First thanks for your detailed reply :)

As far as i remember it was a 15" from EV in a bandpass enclosure but dont quote me on the exact model.

So they are doing it like the internet providers which are telling you up to 50mbi/s but you're getting maybe 16... ( Quite common here in germany). But what you are saying confirms my assumtion and i don't have to worry if my design just goes for example from 45-150 at -3 with a theoretical max db of 131 and still keeping the driver in the "save" xmax. Which leads me to a question regarding your design with the 155N01. How do you achieve a power handling of 2800W in that kind of frequency range without ripping the driver ? In my designs i have always problems to stay in a safe range of xlim/mech Confused


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Post Options Post Options   Thanks (0) Thanks(0)   Quote Hemisphere Quote  Post ReplyReply Direct Link To This Post Posted: 09 August 2017 at 9:01pm
The PD155.N01 is an exceptional driver. It has 10.5mm xmax and it takes a lot of power to get it moving. Oversize magnet, 5" voicecoil. It's a 15" neo but it still weighs 9.5kg. If it was a ferrite or ceramic driver it could be double that.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote dekra54 Quote  Post ReplyReply Direct Link To This Post Posted: 09 August 2017 at 9:09pm
Yes i wanted to buy this one for exactly the reasons you mentioned but unfortunately it wasn' tavailable at the time i needed them ( now it's discontinued Shocked ) and instead i bought the 1550 (which i think is the ferrite version but with a lower xmax of 8.2)
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Hemisphere Quote  Post ReplyReply Direct Link To This Post Posted: 09 August 2017 at 9:22pm
I can't believe it's discontinued either. Bluearan's website suggests they can still get it on order though.

It's confirmation if ever you needed it, that people just don't recognise quality when they see it. 

It wasn't cheap - about 300 GBP, but with amp prices dropping as fast as they are (iNuke 6000W amp for 350 Euros), you can use a driver like that to get literally double the output of a cheaper driver.

An American bloke at the diyaudio forum was recommending a Faital Pro 15FH500 for compact sub applications the other day, but per US prices it's only about $100 cheaper than the PD155.N01. So you could pay $580 plus 2x enclosure costs, or $390 + 1x enclosure material/assembly costs, and get approximately the same result (actually 1x PD at max input = +1.5dB of 2x Faital) . The PD would probably sound better too.


Edited by Hemisphere - 09 August 2017 at 9:29pm
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Post Options Post Options   Thanks (0) Thanks(0)   Quote dekra54 Quote  Post ReplyReply Direct Link To This Post Posted: 09 August 2017 at 9:28pm
Maybe they are collecting orders to get the ~50 MOQ for a custom order?
I just compared the 1550 and 155N01 and there the same exept (at least if I am not mistaken) for the xmax and weight of course.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Hemisphere Quote  Post ReplyReply Direct Link To This Post Posted: 09 August 2017 at 9:48pm
they can't be the same driver. The N01 has a 5" voice coil. 1550 is 4". Also, if it's 12.8kg ceramic and 9.5kg neo, it suggests a stronger magnet on the neo. The only other thing that could make up significant weight is the frame, but aluminium just isn't that heavy.

Edit: Plus anyway the frames, at least, look almost identical.


Edited by Hemisphere - 09 August 2017 at 9:53pm
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dekra54 View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote dekra54 Quote  Post ReplyReply Direct Link To This Post Posted: 09 August 2017 at 9:53pm
Doh' Youre right.  accidently had two tabs with the PD1550 and looked at these LOL better go to bed now....


Edited by dekra54 - 09 August 2017 at 9:56pm
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Mircea Bartic View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Mircea Bartic Quote  Post ReplyReply Direct Link To This Post Posted: 10 August 2017 at 11:44am
I can confirm. Almost everybody lies.

As a manufacturer, it's even easier to lie without being caught when you sell Active speakers.

This phenomenon is starting to appear with the raw speaker manufacturers. Cough ,Eminence,  cough , BMS, Cough, etc. LOL
general manager & head designer at nexus-acoustics research
http://www.facebook.com/nexus.acoustics.research

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