PA sound system

[technofreak]

For midtops - stay away from 15" drivers, they're not the best for midrange. Yes, they can be used with some serious 1,4/5" or 2" CD crossed over at kHz or even less, but using a single 12" or double 10" or 8" and 1" CD is much cheaper and gives better results for money.

Infact, in my opinion, horn loaded 6" is the best for 300Hz to 3 kHz, with 12" or 15" (horn loaded or not) below 300Hz down to 80 Hz or so, and proper subs below.

A versatile and good sounding option would be fullrange cab w/ direct radiating 15" from ~50...300Hz, 6" horn loaded up to 3kHz and 1" CD above that. This should give approx. 125 dB cont. over it's bandwith (compare w/ ~120...122 dB cont. of typical 15" + CD active cab, e.g. "industry standard" RCF ART series) and can be used standalone for smaller discos, spoken word and backround music, and combined w/ good subs for bigger events.

[Darksoulslayer]

hey guys, well, i'm not saying i'm right or wrong ,just wanna thrown a few things around, it seems you guys do know wot you talking about so i hope i'm not going to offend any 1, i'm cuurently a live-sound engineer and also do car sound and the occasional home audio thing, i have not built a PA system yet, but if i were going to there's a few things i would think about,

my first thought is the very low freq. the lower the freq the more power you need to drive it and you need a amp that will control the driver excursion at all DB's and freq (slew rate? i think) and then the said freq will need the x-amount of distance to fully develop its natural
wave form that would give it even more body.........

amplification, well, 1 thing i have learned from car audio is that the more power the beter for the simpel fact that distortion is when an amplifier goes from ac to dc or the other way around, you will not blow a speaker from a 100 or 200 watts rms more than spec, but it needs too be distortion free, but you can blow a speaker of a 100watts with 50watts of power if the amp is distorting, i always amplifie my speakers with atleast 1,6watt amplifier per 1 watt speaker giving you 60% headroom for any discreptensies in the media played, you will still need to use youre ears for over excursion of the speakers but as long as youre not clipping the amps or sending a hot signal from you mixer you should not have trouble....

well,i said wot i thought, i could be wrong, but thanx anyway

[grecon]

As a TH newbie I would be interested to hear all the details about jbells 44hz TH and slot loaded/horn top as "pa on the cheap" is one of my favorite subjects!

[djk]

A quick search shows up:

jbell's set of four tapped horns

[grecon]

Thanks, but I was referring to the 44hz TH in post#26 with the MCM 55-1740 and his slot loaded/ horn tops that use the same driver.

[grecon]

Still wondering if Jbell would like to share some info on his 44hz TH using the MCM 55-1740 as well as his top cabs using the same driver

[jbell]

grecon

just saw your post. Yea, I'll start a thread on it once I have pics, plans, etc drawn up. I'm at work, and don't have all of my stuff in front of me, so this is from memory... (which is questionable sometimes)


I've gone through a few different cabinets on the 55-1740 driver for subs, trying to find the best combination of size / output. The one I think I'm happiest with is this one. (2pi, 2mh choke added, 2 drivers in series, 50v input) The series drivers gives me some confidence that I'm not going to smoke my drivers, and allows me to run up to 4 cabinets on an amp channel. MCM admits the xmax is a typo on that driver and that it's not 4mm, but really longer. MCM won't tell us exactly what it is, but I've measured mine going way past 6 mm, so I'm comfortable using that as xmax.

I started to reply with the top info as well, but it's too easy to confuse things without a pic, so I'll double check my sub info, and draw up my top later.

watch for a post on it in the near future.