cant help you myself but the people on http://www.speakerplans.com/forum/ should nkow there stuff.

Yeah visit that site and ask the question and you should hopefully get a lot of advice.

Is it important that you use those salvaged drivers?

Obviously if you were intending to use them to build a 3 way full range cab then you’d use the 15″ for bass the 10″ for mid and the high frequency driver as the treble. It seems a bit unlikely that this driver would be 600w though unless it’s some kind of inaccurate power rating that has been quoted.

Is the high frequency driver meant to be used as a compression driver with a horn, or is it like a bullet tweeter or peizo. If it needs a horn then you will need to make sure you get one that is suitable for that driver.

As for the actual cabinet you can use a program like WinISD http://www.linearteam.dk/ to design a cabinet around the drivers you have. It will help you match a drivers natural resonance to a specific speaker volume (as in area, not how loud it is) and design.

As you have mentioned you would need a crossover. The cheap route would be to build or get built a passive crossover that will sit inside the speaker to manage the frequencies that the speakers receieve. However this is not ideal, especially with low frequencies. A cheap active crossover would cost you about £75 and this would give you more control over the speaker but will mean you will need to use more amps to power the speaker. You could then have a seperate speakon connection on the speaker for each frequency, or, what would be more effective would be to have an 8 pole connection that you could then distribute inside the cabinet. You would need 6 of the poles… eg a – & + for each driver.

I may be getting a little too far ahead of what you want for the moement. So I wont say anymore. Best place it to ask on Speakerplans as there are some more clued up people on there than me and they will probably be able to explain it in more simple terms.

Good luck.

When you say 3 way crossover, do you mean an external active 3 way crossover (which will likely be a 19″ rackmount box with it’s own power supply), or do you mean you have a 3 way crossover design for fitting into the speaker box itself (this will likely be a small circuit board with a coil or two, a few resistors, and maybe some capacitors and maybe an L-Pad or two depending on design)?

I am assuming btw that the horn driver isn’t 600w as you posted, but is 60w (a 600w tweeter would be a good way to go deaf easily).

If the crossover is external, then you would be better served splitting the speakers up into seperate boxes (you need to align the drivers correctly to minimise phase distortion, and this is easiest done with them split :wink:) It will also stop you from running into too much intermodulation distortion, and will make the designs far more efficient (resulting in more bang for your watts…) You can put them all into one box, but you need to ensure that the drivers are aligned in both vertical and horizontal planes, and the calculations can be a pain to get right (the sweet spot can also move depending on the acoustics of the space they are used in). You will also run into summing errors in a 3 way box – especially at those power levels, because most multi way actives are 3rd or 4th order Linkwitz/Riley design, and you really need to use a 1st order Butterworth for anything more than 2 way….

I have some good designs floating around somewhere that I can try and find for you for single driver boxes – pm me if you do…

If it’s passive crossover, you have fewer options from the point of view of tuning – it can be done, but requires changing components to do it. But it does allow for easier multi driver box design. You basically have to get the signal to the right speakers, with the right bits filtered out… 😉

The most common passive is a 1st order Butterworth network, which uses a low pass filter (consisting of a capacitor, and an induction coil), which drives the low, and also feeds another filter pair (again a coil, and a capacitor), which feed the mid and high. Essentially a cascaded pair of 2 way Butterworth filters (the capacitor value, and the coil winding dictates the frequency of crossover).

The designs get more complex as you go up order (the example above is a 1st order, so a 6db/octave slope at the crossover points – you could make a 2nd order, which is 12db/octave, 3rd which is 18db/octave etc), and there are other more efficient designs (Linkwitz/Riley, Bessel etc) which add impedance attenuation and other fun things, but a 1st order Butterworth is best for a 3 way design because it’s the only one that doesn’t have summation problems from cascading filters (the others are usually used for 2 way boxes)….

I’ve not designed a passive box for a while, so this is the extent of what I can remember (and I can’t find my speaker book at the moment). There is a good page at True Audio that covers most of this however, and a few good links on ePanorama here and here.

Hope it helps…

As it happens, I wouldn’t know where to start with a passive crossover as I’ve never used them. Had you been doing it active then I’d be able to tell you how to wire things.

Seems like you have done your research anyway, eg fitting the 10″ inside a sealed box within the cabinet.

Good luck with it.

I might be completely wrong but from what it looks like on the Maplin website the tweeter is actually 85W (i.e you can feed it with 85W of power, a pretty sensible figure for a tweeter). I think the 600W its referring to is when you’ve got it connected to the IEC 268-5 crossover mentioned on the webpage, so if you’re building a cabinet with 2 drivers in it, u can feed the cabinet with up to 600W without burning out the tweeter. The Maplin description is misleading, probably on purpose to make the thing seem more powerful than it actually is.

85 watts is plenty for a tweeter – 600 is a little ridiculous on a single driver – even ceramic horn drivers (which tend to handle higher power than plastic/phenolic ones) don’t handle more than 200w each. I use a set of 2″ throat ceramics at the moment, and they are only about 80 watts each. And they are the only part that won’t need any upgrading next time I decide it needs to be louder (which will likely entail doubling up on lo, lo-mid, hi-mid drivers). The highs have power to spare, and will easily be loud enough.

Eminence are good drivers though – I use a set of gamma 12’s for hi-mids, and they have been worth their weight…

With the box and the crossover, I would still look at first order Butterworth design – you will get summing errors even with the 10’s sealed, as they are still using the same resonator to amplify themselves (the whole box is a bit like a guitar sound board in that respect – the resonators of the outer and inner boxes interact unless they are independent of each other). You will also need to be sure they are properly in phase too (which will likely be an entertaining experience if you are porting the bass section, but sealing the mid – the speaker/air impedances will be mis-matched, the port allowing for a better match than the sealed one.)

If you have another set of tweeters (the ones you salvaged), you would probably be better served building 2 pairs of ported full range cabs. That way, you would have an extra pair of speakers, and they would both be much more efficient (you could have the 2 boxes stuck together if you wanted, but the ports would make the tuning far easier). The 10’s can do a lot if you give them the right box design – you should be able to tune for a resonant peak of about 40Hz at the bass end, with a cross at about 4KHz to the tweeter. The crossover can be a more precise animal than a 1st order Butterworth that way too, and you don’t need to worry too much about summing and phase (2 pairs of full range, 2 way boxes can be arranged to sound right much more easily, and will require less experimentation to find the right cross point)…

For designs and info on crossovers (2 or 3 way), there are lots of good articles at Shavano music (including the calculations for crossover points, and schematics of different types).

The wiring of the crossover follows the basic rule: coils (inductors) filter out high frequency, capacitors filter out low. Impedance will be the value of the lowest impedance of all speakers The amp only “sees” one speaker as long as the crossover points are the same for both low pass and high pass filters, so with 3 8 ohm speakers, it will be 8 ohm (it may seem to be wired in paralell therefore making the load half, but the crossover makes them frequency specific – essentially presenting a single load to the amp.)

hey all. any help would be appreciated.

my amp broke in a year of me getting it and i luckily got it replaced at the store but i think its my loud speakers ohm that caused it to fail.
i been using some old speakers my mum gave me.

on the back of the 2 speakers it does say 8 ohm but when i look in at the circuitry on both separate loud speakers i see a bass, mid woofer, tweeter all in parallel. i know the bass and mid are both 8 ohm because its wrote on the drivers but the tweeter has no markings on it stating its ohm.

i don’t understand how each cabinet could be 8 ohm as it states on the back of them. if the tweeter was 8 ohm then the math is

mid – 8
bass woofer – 8
tweeter – 8

(8 x 8 x 8) / (8 + 8 +8) = 21.3 ohm that cant be right ?

if the tweeter was 2 ohm the hole cabinet would be 7.1 ohm . but tweeters are normally a much higher than 2 ohm. whats going on here have i got it wrong? was it the speakers that broke the amp? :S

amp spec
*Cambridge audio A5 60w per channel 8 ohm
*speaker impedance 6 ohm – 16

loud speakers
60w

Dunno-if-someone-has=put-this-already-but-the-12″-and-the-10″-drivers-
might-not-like-bein-in-the-same-box-together,gettin-in-each-others-way.
Might-be-worth-designin-seperate-boxes-for-each-on-WinISD-and-then-just
build-it-as-if-its-2-(3-countin-the-tweeter)-boxes-in-one-with-a-divider-in-between.

No – they’re 8 ohm because the boxes will have a crossover (passive) built into them – they only cover part of the avaliable frequency band (impedance is only slightly like resistance – mostly it’s not – the impedance ratings on your speakers are usually a nominal impedance at 1KHz – the actual impedance varies up and down the frequency spectrum – at low frequency it will be lower, and at high frequency it will be much higher).