Building a set of PA speakers, any help appreciated.

[Centauri]

The amp size suggestions I made before would be good match for the capabilities of the drivers mentioned, but would probably be more than you need - your suggestion of 250/400W would probably be fine.

In this case, some of the lower powered Eminence drivers could save a bit more cash. For the sub(s), if you wanted to go 15", and where there is not a big demand on this area, the stamped frame Kappa15 can give lower bottom end than the cast versions and they sound quite nice. Again, for the mids, the pro version is probably not warranted, and even the Gamma12 might be a possiblity.

If you like pinkmouse's suggestion of two top boxes per side, which would be quite usefull, then even the Beta10 in each could do quite well (as well as adding to 4 ohms for better use of the power amp).

Cheers

[Centauri]

As a further note, I usually tend to steer away from 15" + horn combinations, as most 15" speakers have performance issues trying to get to high frequencies (there are exceptions like the EV 15L for instance), which requires using 2" compression drivers and crossover points well within the vocal range - two aspects I have grown to dislike. For jazz especially, I would be aiming for clarity.

Cheers

[5th element]

This all sounds more positive as time goes on

I was also under the impression that the pro units would sound better then the cheaper versions. Do they all sound similar but can just handle more power? Im after a good sound too not just SPL.

Im not sure that a lack of bass would be the problem, maybe four 12" speakers would be better, two used for smaller venues and four used at larger gatherings.

By the sounds of things they use two monitors with 15" for all of them.

Ill have to wait and see what they use now and what they will require. But untill then you lot have given me lots of good advice and food for thought on what drivers to use.

Cheers Matt

[SineEra]

Please see my post in Paulinators thread on hifi PA.
IMHO and 20 years of PA'ing for all types of bands, mainly jazz now, a parametric with variable Q and +/- at least 18db pref 24db is needed to get adequate control over horns particularly with a sax, trumpet.
This followed from an early eighties article in Internal Musician and Recording World where Maryland as state of the art PA suppliers had calculated that with FFT analysis a five channel parametric could virtually guarantee to sort out all PA/venue issues.

The systems mentioned are definite overkill for most venues if the audience still want to hear themselves talk.

Simon

[Cal Weldon]

Originally posted by pinkmouse
In that case, I would go for a pair of 15" plus horn boxes passively crossed over, driven by a 2x300w amp. Keep it simple and small. If they need some more bottom end, you could build a couple of extra 15"s at a later date.

If you build the top boxes wedge shape, you could build a couple identical extra as monitors.

I agree 100%. The tried and true is still is a very good starting point and offers easy expandability.

I always thought, the fewer the drivers AND the fewer different drivers you use, the better. My system is dual 15's in one cabinet and single 15 with comp tweeter through big horns in the other cabinets. Is very nice to listen to whether you are 15 feet or 150 feet away

As my friends keep telling me...

K.I.S.S.

Cal

[sreten]

The pro versions are about handling lots of power, and they
also have parameters which restrict excursion at low frequencies
to achieve power handling, a high power 10" doesn't do bass.

Sound quality is a moot point and a contentious issue,
as is power handling and sound coverage.

IMO 50W stereo valve for the tops would be more than
enough with high efficiency and sound very nice to boot
- but unfortunately most second hand valve kit is mono.

So I'd say a 100W per channel powered desk would be fine.

Vertical 4 x 8's + vertical tweeter array can sound nice with
a good horizontal spread. Presumably due to BSC the ones
I've come across are quit wide and not deep, but this is
a route to superior midrange.

As is the Peavey 6x6, used in a 2 x 3 array, with the left and
right pairs angled underneath a largish quality treble horn,
though this unit is really a top unit only designed to be used
with an additional bass cab, or on its own for vocals and guitar
etc only, not keyboards.

I'd suggest midrange quality is an issue here over the
more normal "rock" requirements of earsplitting SPL's.

4 Audax AP210G6's would be 6ohm, around 98dB/W
and with 5mm excursion (+/- 2.5mm) compare more
than favourably with a 100w 15" PA bass unit,
without the midrange being all over the place.

£13 each when 5 or more from Maplins.
I'll let you work out the alignments possible.
Rated as a 100 Watts they'd be fine IMO.

Once you decide your not going to use the typical rise in
midrange output of a PA driver, or put 300W through it
their major advantages begin to dissappear.
The typical rise is 10dB or more and for small cabinets
if you add baffle step it typically reaches around 15dB
or more, any wonder a typical unit with simply a piezo
added in parallel sounds awful ?

Food for thought ?

Just seems to me your still building a "rock" PA.

sreten.

[pinkmouse]

Interesting idea sreten. A couple of things that would worry me about the AP210 drivers though, are the power handing and the general robustness.

I know that Audax are usually pretty conservative about power rating, so the rated 50W, ( from what I remember!), might well be OK, but the APs use plastic baskets, so I would worry about them being thrown in and out of cars and venues. From what I remember, the magnet is pretty heavy, so it might not take much of a knock to missalign something.

But I do still like the concept though, I will start thinking about other possible drivers!

[5th element]

I am also interested in sretens idea too, that sounds like it would sound much better with jazz. What was the idea to do a line array with horn to the side running vertically like a ribbon would?

I also dont think my uncle will "throw" anything around but I take your point about the poly basket. The nice thing about the audax units is they are cheap. Using vifa's or peerless drivers would cost a whole heap more.

[pinkmouse]

A line array would give yuo nice horizontal dispersion, but you would need to bear in mind the directivity of the horn. It would need to have the long axis horizontal to give matching coverage. A 2x2 array might give the most compact box, with the horn on top, or maybe an MTM, again a design that could be used as a monitor wedge, because dispersion is not so imprtant in the near field, the fact that the horn was the wrong way up would not be a problem.

[sreten]

Originally posted by pinkmouse
Interesting idea sreten. A couple of things that would worry me about the AP210 drivers though, are the power handing and the general robustness.

I know that Audax are usually pretty conservative about power rating, so the rated 50W, ( from what I remember!), might well be OK, but the APs use plastic baskets, so I would worry about them being thrown in and out of cars and venues. From what I remember, the magnet is pretty heavy, so it might not take much of a knock to missalign something.

But I do still like the concept though, I will start thinking about other possible drivers!

Power Handling :

I sold some sealed box speakers around 20L using an 8" 50W
Audax bass unit from Maplins to an utter party animal years
ago. As far as I know they are still going strong after years
of full graphic bass boost, extra bass button and house music.

Robustness :

You can always regard the plastic chassis as having some shock
absorbing properties, they can't get bent like cheap steel chassis.

sreten.