|
Dual 15" mid/highs upgrade |
Post Reply 
|
Page <123> |
| Author | ||
mini-mad 
Old Croc 
Joined: 13 July 2012 Location: london Status: Offline Points: 6903 |
 Post Options
 Thanks(0)
 Quote Reply
 Posted: 17 June 2018 at 2:25pm |
|
|
Haven't come across a 15 that sound nice (to my ears) for vocals yet.. I'm not saying they don't EXSIST I'm just saying I have always preferred the sound of a smaller driver for midrange... but that's for the heads up!
|
||
|
If it sounds like a gorilla is trying to escape, turn it down.
|
||
 |
||
|
toastyghost
The 10,000 Points Club 
Joined: 09 January 2007 Location: Manchester Status: Offline Points: 10919 |
Post Options
Thanks(0)
Quote Reply
Posted: 17 June 2018 at 2:29pm |
|
Depends on how they're used… |
||
|
||
|
Jack_The_Ripper
Registered User 
Joined: 04 March 2018 Status: Offline Points: 214 |
Post Options
Thanks(0)
Quote Reply
Posted: 17 June 2018 at 2:42pm |
|
|
Hemisphere and Elliot...
Thanks guys I thought the RCF MB15N405 would be a better option, compression driver wise maybe the 18 Sound ND3T would be better : I'm not sure i'd wanna put anymore than 150 watts continuous average power (what people call RMS) into the compression drivers and 3,000 watts average power into each pair of dual 15" RCF MB15N405 drivers because I play techno and some of the tracks look to have as little as a 1.5db-2db crest factor due to being very heavily compressed. I don't fancy selling the mid/highs and trying to find or getting some made a pair of dual 12" cabs I can't be doing with the hassle. Edited by Jack_The_Ripper - 17 June 2018 at 2:44pm |
||
|
||
|
Jack_The_Ripper
Registered User
Joined: 04 March 2018 Status: Offline Points: 214 |
Post Options
Thanks(0)
Quote Reply
Posted: 17 June 2018 at 2:43pm |
|
Actually the JBL SRX725 sound very good in the midrange to be honest.
|
||
|
||
|
Conanski
Old Croc
Joined: 26 January 2006 Location: Ottawa, Canada Status: Offline Points: 2537 |
Post Options
Thanks(0)
Quote Reply
Posted: 17 June 2018 at 4:57pm |
|
I have a set of double 15+2 cabs that get used the same way(always with subs)... just had them out yesterday on a parade float. These boxes are easily the smoothest sounding I have, none of my 1" exit boxes come close particularly at higher output levels. In my case the boxes are loaded with mid/bass drivers that don't have much output below 60hz, 3" VC, short xmax(Kappa Pro15) and it only takes 2 parametric filters to produce flat response up to the 1khz crossover with the CD. I know there is lobing with 2 large "mid" drivers like this but honestly it's not obvious, the increase in output is easily worth it. I bought these cabs unloaded specifically for this type of use, a big CD is wasted on a single mid/bass driver IMO. My only complaint is the weight.. at 150lbs my cabs are a handful, I'd love to swap in neo drivers but I can't justify it for the amount they get used. |
||
|
||
|
ceharden
The 10,000 Points Club
Joined: 05 June 2005 Location: Southampton Status: Offline Points: 11776 |
Post Options
Thanks(0)
Quote Reply
Posted: 17 June 2018 at 5:56pm |
|
|
Yes, 2x15" + 'HF' cabs are never going to be as good as 12" or 10" versions in terms of midrange. However, with careful driver choice, including the compression driver and horn it is possible to get perfectly acceptable and very useable results.
I look after two local installs both of which use different cabinets and drivers but both with the same 2x15" + 2" configuration. Some key points from my experience: * It is essential to use a compression driver with a minimum 3" diaphragm. The two examples I work with have DHA1a and DE85. 1.4" or 2" exit. * A BIG horn/waveguide with a cut-off frequency well below 1kHz. Again, I'm talking something with a 500x300mm mouth. * The two above points allow you to run a crossover frequency in the 1-1.2kHz range * A 15" driver with a smooth response to well beyond 1kHz. I suspect the suggested MB15N405 is very similar to the MB15H401 ferrite driver which I've found works very well in this application * Bi-amp with a decent LMS, phase align the 15" and HF. |
||
|
||
|
Jack_The_Ripper
Registered User
Joined: 04 March 2018 Status: Offline Points: 214 |
Post Options
Thanks(0)
Quote Reply
Posted: 17 June 2018 at 6:25pm |
|
|
The crossover point in the cabs as standard is 1.8khz but I was thinking about 1.5khz crossover frequency on my dbx Driverack PA2. Phase alignment is something i'm not knowledgeable in but i'll try and learn about it. At the moment the passive crossover is a quasi 3-way the lower 15" driver and top 15" driver operate at seperate frequencies. When it comes to bi-amping should I take out the passive crossovers and just connect the two 15" drivers to pins 1+/- and 2+/- and the compression driver to pins 3+/- and 4+/- and use 4 core 4.0mm speakon cables?
|
||
|
||
|
ceharden
The 10,000 Points Club
Joined: 05 June 2005 Location: Southampton Status: Offline Points: 11776 |
Post Options
Thanks(0)
Quote Reply
Posted: 17 June 2018 at 6:38pm |
|
|
For best results you need to remove the passive crossovers and run on separate amps.
Unless you're running long distances, 4mm cable is probably unnecessary. 2.5mm should be fine. You should aim to get the crossover frequency as low as your compression driver and horn can safely support. |
||
|
||
|
Jack_The_Ripper
Registered User
Joined: 04 March 2018 Status: Offline Points: 214 |
Post Options
Thanks(0)
Quote Reply
Posted: 17 June 2018 at 7:20pm |
|
|
The minimum reccomended crossover frequency for the 18 Sound ND3T is 1khz. Should I use Butterworth 18db/oct or Linkwitz Riley 24db/oct slopes? By the way speakon cable length I have 6.0mm Van Damme Tour Grade for the four double 18" subs which are being run one sub per channel on two Proline 3000 amps. I have 4.0mm Van Damme Tour Grade speakon cables that I bought for the mid/highs (again 2 core, obviously i'll need two new 4 core cables to biamp). The cables are all 5 metres long from speakers/subs to amps.
Edited by Jack_The_Ripper - 17 June 2018 at 7:24pm |
||
|
||
|
Hemisphere
Old Croc
Joined: 21 April 2008 Status: Offline Points: 2272 |
Post Options
Thanks(0)
Quote Reply
Posted: 17 June 2018 at 8:28pm |
|
Isn't there a piece of software you can run to analyse the crest factor of a track? High pass the whole thing as it would be in your system then analyse it the sections which look the most dangerous to you to see what the risks really are. Bound to exist, probably as freeware, as it's such a basic piece of vital information. Obviously running the tracks into clip would mess with that readout, but when running a track into clip it's usually the frequencies below 100Hz which are clipping, unless you've got an MC screaming into the mic or something equally silly, but you should, if your DSP has the option, limit your mids and highs a lot more strictly than your bass, as they really sound awful in clip. A continuous maximum amplitude sinewave has a crest factor of 3dB, as a point of reference. Music doesn't play continuous maximum amplitude signals for more than a few milliseconds because it counterintutively causes the program material to be perceived as less loud than if the notes have a few ms of 'bite' followed by a drop in amplitude (though the amplitude of the same notemay then be ramped up again, but still invariably following an ASDR envelope if it's to remain even slightly musical, and I do mean musical by techno standards. Zoom right in on the signal if you're not sure, and filter out the freqs below 100Hz first. You shouldn't even need software to see the signal isn't half as compressed as you're thinking. 1.5kw per driver sounds sensible in any case and will give good results, if that's the plan you have for amps. More than that will mostly be ploughed into power compression + associated risks. I guess if you don't know what's going to be playing through your system and you let some DJ on to play some idiot ear-breaking system-breaking sustained clipped signals above 100Hz sort of music you might be in trouble, but that's what RMS limiters are for.
Edited by Hemisphere - 17 June 2018 at 8:33pm |
||
|
||
|
Conanski
Old Croc
Joined: 26 January 2006 Location: Ottawa, Canada Status: Offline Points: 2537 |
Post Options
Thanks(0)
Quote Reply
Posted: 17 June 2018 at 8:39pm |
|
|
||
|
||
|
Timebomb
Old Croc
Joined: 11 October 2004 Location: Lancaster Status: Offline Points: 2716 |
Post Options
Thanks(0)
Quote Reply
Posted: 17 June 2018 at 9:00pm |
|
Audacity and "RMS Calculate" plugin works, there both free, its quite easy to add highpass or lowpass to give the band of program material you want to analyse. you will need to highlight the section of the track you at looking at and normalise so it peaks at 0dB. Ive been testing some heavy bass dance music and it rarely drops below 8dB crest factor
|
||
|
James Secker facebook.com/soundgearuk
James@soundgear.co.uk www.soundgear.co.uk |
||
|
||
|
Post Reply
|
Page <123> |
| Tweet |
| Forum Jump | Forum Permissions You cannot post new topics in this forum You cannot reply to topics in this forum You cannot delete your posts in this forum You cannot edit your posts in this forum You cannot create polls in this forum You cannot vote in polls in this forum |
Topic Options
mini-mad wrote: