PA speakers help ... - diyAudio
Go Back   Home > Forums > Live Sound > PA Systems

PA Systems A forum for discussion of all parts of a sound reinforcement or DJ system: loudspeakers, mixers (desks) etc.

Please consider donating to help us continue to serve you.

Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving
Reply
 
Thread Tools Search this Thread
Old 10th July 2012, 08:09 AM   #1
diyAudio Member
 
east electronics's Avatar
 
Join Date: Jan 2006
Location: Athens GREECE
Default PA speakers help ...

I own 4 of these as seen in the pictures bellow .Usually working in small venue or open area for a crowd of 800 people max ( depending on the application with subs or not )

I run them at about 500W per speaker Inside exist a passive crossover between woofs and tweeters

the original speaker can be found either as sound king F2215 or audiomaster F2215

Original 1.75 drivers inside failed quite often and actually not form coil issues but from mechanical pov I replaced them PSD20028S from eminence

After that had no driver issues but the middle of the speaker was kinda weird emphasis somewhere in 2K required serious equalization to produce a listenable result . I had in mind that this was an xover issue but run it like that with absolutely no probs from failure aspects

last night decided to listen to them active used a xover from behringer 2 way and out of the blue the speaker become very rich and balanced no equalization needed both controls at 0db an cross them at 3.2 KHZ

------------------------------------------------------------------------

Question 1
I dlike some advice if the xover frequency is ok ( sounds ok to me and also have the impression that i could go even higher without producing a problem in the high mid or in the mid generally

Question 2
If i decide to run them active do you recommend any aditional safety measures in the HF driver such is a lamp (s) or a capacitor or is it enough to connect directly the HF driver to the amplifier ?


any other ideas are welcome

here is some pictures of the speaker , the woofers and the drivers

thanks for your time

kind regards
sakis

Click the image to open in full size.


Click the image to open in full size.


Click the image to open in full size.


Click the image to open in full size.
__________________
SERVICE ΕΝΙΣΧΥΤΩΝ ΚΑΙ ΙΑΠΩΝΙΚΩΝ ΜΗΧΑΝΗΜΑΤΩΝ ΗΧΟΥ www.eastelectronics.gr
  Reply With Quote
Old 10th July 2012, 02:44 PM   #2
diyAudio Member
 
east electronics's Avatar
 
Join Date: Jan 2006
Location: Athens GREECE
some forum trouble ??? seen my post ...posted twice ?
__________________
SERVICE ΕΝΙΣΧΥΤΩΝ ΚΑΙ ΙΑΠΩΝΙΚΩΝ ΜΗΧΑΝΗΜΑΤΩΝ ΗΧΟΥ www.eastelectronics.gr
  Reply With Quote
Old 10th July 2012, 09:20 PM   #3
diyAudio Member
 
Join Date: May 2010
I'd be a bit surprised if you were actually seing a flat response from the speakers with the crossover set at 3.2 KHz. It would be interesting to know what the slopes were, too.

Get an RTA mic, that the speaker outdoors and start moving the crossover frequency up and down to see what the flattest response is that you can get without EQ. Then apply EQ to get a decently flat response. That would be your starting point to adjust the EQ for individual venues.
  Reply With Quote
Old 11th July 2012, 12:39 AM   #4
dangus is offline dangus  Canada
diyAudio Member
 
Join Date: May 2004
Location: Vancouver Island
You should figure out how the original crossover is wired. Try and set up a sound card and run something like Speaker Workshop to measure the electrical and acoustic response. It's useful to plot the electrical response of a crossover; that will graphically show the value of the Zobel. At the very least, play some pink noise and use a smartphone or laptop or tablet running RTA software to see the response.

Light bulb limiters are a good idea on the tweeter. I tried a couple of automotive tail lamps with both filaments wired in series. When a live PA produced some excruciating squeals using a Kaoss Pad, the bulbs lit up. Someplace, though, I've got the part number of a bulb which is actually used in commercial speakers.

For what it's worth, somebody told me that 16 ohm compression drivers were tougher, so I got the 16 ohm version of the PSD2002, then wired a 15 ohm 20 watt resistor in parallel, which lets me a) feel how much real power is going to the tweeters, and b) makes for a more resistive load so the crossover hopefully works better. The crossovers are old Altecs, with the caps replaced by Solen film capacitors.
  Reply With Quote
Old 11th July 2012, 05:56 AM   #5
mdocod is offline mdocod  United States
diyAudio Member
 
Join Date: Dec 2011
Location: Black Forest, CO
Send a message via AIM to mdocod
A PAIR of 15" drivers covering the same frequency range, if used above ~700-800hz will suffer from off axis destructive coupling kicking in noticeably as shallow as ~10 degrees off the design axis. For usefully flat response at 20 degrees off of the design axis, they would have to be crossed no higher than ~400hz, or potentially configured as a 2.5 way. Furthermore, very few 15" drivers have much useful response above ~1200hz anyway, you start running into cone break-up modes on most 15" drivers centred ~1500hz or so.

There's a reason for the mantra "less is more" in this industry. The reality is that, a well thought out set of compact, easy to move TM's with a single 10-12" midbass driver and a good CD that can hand a low crossover point, backed correctly by subs, will trounce all over most of the big TWW with 15" drivers you see.

The best thing you can do, is perhaps put them back together, pad the tweeter a bit to make them more tolerable, then sell them to the first unsuspecting victim with cash.

I'm not sure it's worth the cost of upgrading these things to usable status.

Regards,
Eric

Last edited by mdocod; 11th July 2012 at 05:59 AM.
  Reply With Quote
Old 11th July 2012, 09:41 AM   #6
diyAudio Member
 
east electronics's Avatar
 
Join Date: Jan 2006
Location: Athens GREECE
Quote:
Originally Posted by mdocod View Post
A PAIR of 15" drivers covering the same frequency range, if used above ~700-800hz will suffer from off axis destructive coupling kicking in noticeably as shallow as ~10 degrees off the design axis. For usefully flat response at 20 degrees off of the design axis, they would have to be crossed no higher than ~400hz, or potentially configured as a 2.5 way. Furthermore, very few 15" drivers have much useful response above ~1200hz anyway, you start running into cone break-up modes on most 15" drivers centred ~1500hz or so.

There's a reason for the mantra "less is more" in this industry. The reality is that, a well thought out set of compact, easy to move TM's with a single 10-12" midbass driver and a good CD that can hand a low crossover point, backed correctly by subs, will trounce all over most of the big TWW with 15" drivers you see.

The best thing you can do, is perhaps put them back together, pad the tweeter a bit to make them more tolerable, then sell them to the first unsuspecting victim with cash.

I'm not sure it's worth the cost of upgrading these things to usable status.

Regards,
Eric
..... ok then all of these speakers made by peavey or Jbl configured as 2X15" +1-2" HF are to be thrown away .... sorry don't really get it ...
__________________
SERVICE ΕΝΙΣΧΥΤΩΝ ΚΑΙ ΙΑΠΩΝΙΚΩΝ ΜΗΧΑΝΗΜΑΤΩΝ ΗΧΟΥ www.eastelectronics.gr
  Reply With Quote
Old 11th July 2012, 10:21 AM   #7
diyAudio Member
 
picowallspeaker's Avatar
 
Join Date: Apr 2007
Eric is right , as he exposed the knowledge acquired and used for 'home reproduction' .
The fact is that for 'live' applications , opposed to sound 'reproduction'
the listener might be more focused on the feeling rather than on the perfectness and so on ...
Also in free air environment the characteristic of sound dispersion are different
and the 'masking' due to nasty interactions might be less audible , since
it might not be associated ...well , it's a matter of dB/decay and distance ,so
the 10-20-30 dB masking might decay in a few time and distance .
For an 'hifi' home user those boxes may appear coloured ,lifeless ,stupidly big
but for a 'pro' user those might be the minimum usable for a live jig .
The benefit from biamplification is also readily recognized from the ears/brain
as a step from passive , as there is a little incremental in dynamics .
The protection cap on the tweeter should then have a value about 2 octaves below the cutoff point , so a 150-200 uF should be ok
  Reply With Quote
Old 11th July 2012, 11:04 AM   #8
diyAudio Member
 
east electronics's Avatar
 
Join Date: Jan 2006
Location: Athens GREECE
well i am sorry to say that so far the information i got so far is hardly usable

150 -200 mfd in series with a HF driver will prevent nothing except DC from amplifier in case of failure

in the PA business exists way too many speakers like the above and many of them from trusted manufactures like the ones and many more mentioned above

hifi or home use was never in question in this post

other than that its a common practice in 2 way speakers to cross the HF high enough to preserve safety and a ""natural gap" in high mids

will set up active in my next gig
set up will be 4 of those speakers running with
PSA 31500 2X575W rms @ 8R times 2 for the woofs ( class H )
PSA 31300 2x 300W rms @ 8R for the HF drivers ( class AB )

active x over behringer and so on

in between since this is going to be DJ set up and will have free time i might as well RTA the system to see how will it work

thanks so far though
kind regards
sakis
__________________
SERVICE ΕΝΙΣΧΥΤΩΝ ΚΑΙ ΙΑΠΩΝΙΚΩΝ ΜΗΧΑΝΗΜΑΤΩΝ ΗΧΟΥ www.eastelectronics.gr
  Reply With Quote
Old 11th July 2012, 12:45 PM   #9
mdocod is offline mdocod  United States
diyAudio Member
 
Join Date: Dec 2011
Location: Black Forest, CO
Send a message via AIM to mdocod
Quote:
Originally Posted by sakis View Post
..... ok then all of these speakers made by peavey or Jbl configured as 2X15" +1-2" HF are to be thrown away .... sorry don't really get it ...
A TWW w/15" drivers done properly is a very rare breed. I suspect it's possible that there might be some very fancy variations out there at very high cost that pull it off well (2" compression drivers with very low crossover points as a minimum, some baffle step loss in a .5 way would be even better since most people position these things out far from boundaries).

The "hifi" approach here, should not be ignored, it applies to all levels of sound reproduction. We are seeing the same principals, applied on a larger scale, at large events around the world. Producing an effective line or point source, and coupling the bass properly means that everyone in the crowd hears something fantastic. You can pretend like what they are doing is voodoo, or learn what's going on that makes it so right and implement it yourself.

For the most part, this TWW w/15" woofer configuration of drivers was put together to appeal to the masses. They look big, and sound big, so lots of them were sold. The sales of this configuration, was, unfortunately, not driven primarily by sound quality, but rather, a false perception in the buying market.

I have nothing to gain here by telling the sad truth. I can run the simulations, and see the flaws in these designs clearly. The only I thing I intend for here, is that, someone who has reached out this far, get the best advise I have available.

Sorry, it's a pile of rubble unless serious cash and research, perhaps the aid of simulation, and ideally, measurement, is sunk into it.

Regards,
Eric
  Reply With Quote
Old 11th July 2012, 02:19 PM   #10
diyAudio Member
 
east electronics's Avatar
 
Join Date: Jan 2006
Location: Athens GREECE
WELL ok

there is a lot of things that you say and i understand and presumably also correct still your missing the point though

the point is that simply these are the given facts the point here is how to achieve the best from this system as is ... i am not willing to replace or invest one euro to this system still though my target is to get the maximum in aspects of quality /power / durability ....

so any advice is welcome taken ...the given facts

kind regards
sakis
__________________
SERVICE ΕΝΙΣΧΥΤΩΝ ΚΑΙ ΙΑΠΩΝΙΚΩΝ ΜΗΧΑΝΗΜΑΤΩΝ ΗΧΟΥ www.eastelectronics.gr
  Reply With Quote

Reply


Hide this!Advertise here!
Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
PA speakers help ... east electronics PA Systems 8 12th July 2012 08:17 PM
5.1 DIY kit with on PA speakers (or good & small DIY kit with PA speakers) ? jm_kzo Multi-Way 54 22nd April 2009 07:54 PM
Built differences between Guitar Speakers and PA Speakers? agadis PA Systems 7 24th September 2007 08:22 AM
PA Speakers Petrix Multi-Way 4 11th November 2004 09:25 PM
New PA speakers! Nappylady Multi-Way 0 9th September 2003 04:23 PM


New To Site? Need Help?

All times are GMT. The time now is 04:53 AM.


vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2014 DragonByte Technologies Ltd.
Copyright 1999-2014 diyAudio

Content Relevant URLs by vBSEO 3.3.2