Midrange and Tweeter Compact Speaker

[shyamwestwind]

HI Everyone
I have a very efficient woofer section consisting of two passive woofer boxes with a very good bass throw of 650 W RMS, from each. I have an 800 W dB Sub woofer to give those real lows.
This means I have three speaker enclosures effectively giving an out put of 2100 Watts RMS.
What I have now for the "tops" are just two dB Opera Lyrics, powered of 275w RMS each. and the sound is very "shrieky" and I feel the need for some healthy MIDS
Can someone give me suggestions for a good Mid/Hghs Speaker System, preferably passive which can have the capabilty of delivering good clean sound from 100 or 150 Hz to 15 k, incorporating a mid frequency in the middle ? All in a single compact cabinet, maybe using a 15" , a 12" and a horn loaded tweeter ?
I just need two COMPACT speaker systems to handle about 700 Watts per enclosure, with mids and highs . I am not sure of how a mid horn handles but if they are good , then maybe those can be used.
Any suggestions?

[moonie]

G'day Shyamwestwind, just at a guess going by the specs you've given, you're not too far short of power on the top end, 400w per side should work nicely and brings a lot of standard speakers into consideration, if you're happy with plastic moulded boxes these are good
RCF - ART 322-i, if you prefer wooden enclosures Acoustic Sound Systems make a very nice box. BUT is it merely a question of EQ? [the "shrieky" ness]

[shyamwestwind]

Hi moonie
Actually it is the shriekiness thats bugging and I'm seriousl;y thinking of making a top with one 12" full range speaker of atleast 400 Watts and horn tweeters. I have the dB Opera 415 now (plastic bodied) and its too shrieky when you use it as tops, though it isnt too bad at small venues if you use only them without the separate woofs. I cross over at around 100 Hz.when I use them with the woofs
The dB Operas are only 275 Watts eaxh and dont have much of "throw" which is why I'm searching for a comfortable mids and highs combination with more power
Yes the wooden boxes make a lot of difference and I think I'll handle the weight for the sake of good sound !!
Any suggestions ?

[JohnG]

Hi Shyam,

"Throw" isn't really an appropriate word to use when talking of mid-range and high frequency units (or squawkers and tweeters if you prefer) only for Bass units (woofers). They have to move long distances to reproduce low frequency sound and we refer to the distance the cone travels as "throw". Bass units will be 18, 15, 12 or even 10 inches diameter. Depends on acoustic power needed at the venue and the extension (how low they go). We need high power amps to push those big cones backwards and forwards.

In building amps for speakers, the higher you go up the frequency range the less power is necessary as the size of the speaker needed to reproduce that frequency becomes smaller. So saying you want to use a 12 inch for high frequencies makes no sense. A 12 inch unit cannot create good high frequencies. Physics. A good mid frequency unit will be about half that size or less. So look for 10 inch but maybe even better an 8 inch unit or multiples of 8 or even 6 inch for mid.

A high frequency unit is even smaller. It's to do with the size of the wavelength of sound which reduces the higher you go. So a high frequency unit is likely to be just an inch or an inch and a 1/4 across. Stick 400 watts across that and watch it disintegrate in a puff of smoke. Great fun but kinda expensive! N.B. Don't stand in front of it when you experiment, it may go off like a bullet as it burns!!!! So too much power at mids and highs can be a BAD thing.

A couple of hundred watts is all that is usually needed to power a mid frequency driver and maybe 50 for HF. Shriekiness is either due to poor equalisation or more likely to the devices being overdriven which is saying the same thing but in another way.

So a better way to produce more mid and hf volume might be (note might be) to buy another pair of the Operas or something similar and use them in addition to what you have, but don't drive them as hard. i.e. don't turn them to full power.

I personally use active units and just add more cabinets as the venue gets bigger, daisy chaining them ,which is easy with active units. I have two active subs (35Hz to 120Hz) but much of the time only really need one, and five light active units with 10 inch LF/MF drivers and 1 inch HF (I think) (85Hz to 18.5KHz), mostly I use just 3 units. (One as an on stage monitor). I know that the music type I support doesn't need anywhere near the SPLs that are used for rock etc. so I think my total (RMS) is probably less than a thousand. If I need to do a really big venue then I hire an extra pair (or two) of active cabinets for the night.

The few professionals I know use this approach, just adding more cabinets (LF, MF and HF), as more acoustic power is needed.

But then of course others may differ.
Hope that helps.
Just my 2p worth.
JohnG.

[gibbo]

One other thing, Shyam, you already have a full range speaker and you won't really get the sound you want by adding "midrange and tweeters". You have to wrap your head around this fact; it's not mids and highs you want, it's LOWS, mids and highs. The subs are only producing sub-harmonic frequencies ie: below 100hz per your set up which equals very low frequencies that sound like "doof doof" rather than lows/bass. You probably have a big hole in your sound from about 100 to 300 hz which is where you'll get the warmth that'll balance out the perceived "shriek". I've used the Operas many times and when they're set up properly they sound great. It sounds like either an eq problem or you're over-driving the horns, you probably need to make the 15s work harder and back off the horns. The 15s will usually always sound warmer than 12s.
Download a freeware real-time frequency analyser (RTA) for your pc or borrow a hardware one from somewhere and check out what frequencies your speakers are actually outputting in the real world (ignore the specs and find out what they're really putting out, I guarantee you'll be surprised).
You should definitely be able to get a good sound out of them without going to the huge expense of buying new speakers (not to mention the weight!).
I have 3 different PA configurations for different sized gigs and I can get a good sound out of any house system we use. It's all about correct setup, eq, and signal chain.
Good luck, Dave.

[JohnG]

I suspect Dave may be right here Shyam.