Any suggestions would be greatly appreciated here guys.
I've recently revived an old set of PA speakers which I'm using. The speakers were active with a passive originally but I've now converted them to both passive because they were basically trashed. The bass drivers and cabinets were fine, however, the horns were dead and the electronics that was in there was pretty much dead as well. I did manage to fit some cheap piezo horn tweeter same size replacements in there, but these things sound pretty horrendous in comparison to the horn drivers that were in there. I fitted an in line capacitor as well as some recommend, not even sure you have to do this even with piezo, but I did it anyway.
To cut a long story short I've now fixed the bullet horns and fitted some new diaphragms in them and they sound much better. I haven't fitted them yet though as I need some sort of high pass filter or crossover before I send any serious power to them.
Can anyone recommend me a cheap crossover, high pass filter or adjustable something or other that I can fit to protect them when I install them, please?
Another option I am looking at perhaps later is maybe fitting some larger horns in there like these.
https://www.amazon.co.uk/dp/B002DUJ...olid=3EAJ2PQM2B4KJ&psc=0&ref_=lv_ov_lig_dp_it
As I do like the sound of a larger compression horn, so that might be a better option rather than buying a crossover, but I expect Id need to buy a crossover for these anyway. And how that will affect the balance of the sound is another thing, maybe it would need an adjuster of some sort, but I do have an eq on my PA.
Anyway, the horns that are ready to go back in are the same type as this
Fostex FH27 – Thomann UK
Heres one speaker with the piezo fitted at the moment
I've recently revived an old set of PA speakers which I'm using. The speakers were active with a passive originally but I've now converted them to both passive because they were basically trashed. The bass drivers and cabinets were fine, however, the horns were dead and the electronics that was in there was pretty much dead as well. I did manage to fit some cheap piezo horn tweeter same size replacements in there, but these things sound pretty horrendous in comparison to the horn drivers that were in there. I fitted an in line capacitor as well as some recommend, not even sure you have to do this even with piezo, but I did it anyway.
To cut a long story short I've now fixed the bullet horns and fitted some new diaphragms in them and they sound much better. I haven't fitted them yet though as I need some sort of high pass filter or crossover before I send any serious power to them.
Can anyone recommend me a cheap crossover, high pass filter or adjustable something or other that I can fit to protect them when I install them, please?
Another option I am looking at perhaps later is maybe fitting some larger horns in there like these.
https://www.amazon.co.uk/dp/B002DUJ...olid=3EAJ2PQM2B4KJ&psc=0&ref_=lv_ov_lig_dp_it
As I do like the sound of a larger compression horn, so that might be a better option rather than buying a crossover, but I expect Id need to buy a crossover for these anyway. And how that will affect the balance of the sound is another thing, maybe it would need an adjuster of some sort, but I do have an eq on my PA.
Anyway, the horns that are ready to go back in are the same type as this
An externally hosted image should be here but it was not working when we last tested it.
Fostex FH27 – Thomann UK
Heres one speaker with the piezo fitted at the moment
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https://cpc.farnell.com/c/audio-vis.../speaker-crossovers?searchref=searchlookahead
Select the frequency you need and choose one.
Piezo do not need a crossover.
Select the frequency you need and choose one.
Piezo do not need a crossover.
There is no scenario in a PA application where a high frequency driver can be safely employed without a crossover and that includes piezos so this isn't just about protection it's a basic requirement. The most basic crossover is a single capacitor inline with the driver and that may be sufficient given what I see in the pics.. this doesn't look like a particularly high power speaker system, but it may also need an L-pad to match levels with the woofer. Look that term up, there are variable versions which are just high power potentiometers but an l-pad can also be constructed using power resistors once it has been determined how much attenuation is needed.
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Thanks Conanski, I was told way back when I bought the piezos that a crossover was not needed and they could be wired directly, but I put a capacitor on just as a precaution anyway. Good call for the L-pad I will look into it. Im am thinking of going for the larger horn now as well so it'll probably be more efficient than the smaller one thats in it, it'll need balancing out I expect.
Its not huge power we are talking here perhaps 150 watt each as that what the tweeter horns are rated at anyway, theres no value on the bass drivers but I expect they'll handle a little more, the PA I have is capable of 3x that, I just use it wisely. The speakers I have are big enough for my needs having 12" bass drivers.
If you decide to use the Fostex FH27 tweeters, and don't want to spend a lot of money on an elaborate crossover network, then I suggest you put a 2.2μF polypropylene capacitor in series with each tweeter e.g. 2.2 df Monacor MKP Capacitor
If you decide to use the larger mid/high frequency horns then use a larger value capacitor e.g. 6.8 fd Monacor MKP Capacitor
Regarding crossovers for piezo horns, here's some valuable information:
Frugal-phile | Piezo Tweeter Crossovers | J Risch
If you decide to use the larger mid/high frequency horns then use a larger value capacitor e.g. 6.8 fd Monacor MKP Capacitor
Regarding crossovers for piezo horns, here's some valuable information:
Frugal-phile | Piezo Tweeter Crossovers | J Risch
Thanks, thats very useful information. And good to know what capacitors to use.
I've found some cheap crossovers as well which may do the job.
2-Way Crossover 12dB, 8 Ohm, 250W, 2.5kHz
https://www.amazon.co.uk/gp/product/B003GSTV08/ref=ppx_yo_dt_b_asin_title_o00_s00?ie=UTF8&psc=1
I think I will at least try the larger horns. Over the years I have had experience with the wider type horn and I really like the sound they throw out. It'll take a little bit of modification to the front plate, but I think it may be worth the little bit of hassle it takes to do that.
I have to say though the piezo that I used for a temporary replacement is not much more than a glorifed door bell, and not even a good one at that. At least it was better than nothing.
Still looking for an l-pad, but I do have the eq to fall back on so long as the high pass filter is in place for the HF.
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First order crossovers should be avoided for PA use - they don't provide nearly enough attenuation of the lower range for the tweeters to survive.
I'd consider 12dB/octave as a minimum. 24dB/octave is preferred.
Chris
Chris is right, and that Amazon crossover could be bettered at a similar cost.
I suggest letting the bass speakers run 'full range' and using a 12dB/octave high pass filter on the mid/high horns.
Put a 4.7uF capacitor in series with the horn and a 0.6 mH inductor in parallel with the horn.
4.7 fd Monacor MKP Capacitor
0.60 mH Air Cored Inductor
See what the sound balance is like before worrying about an L pad.
I suggest letting the bass speakers run 'full range' and using a 12dB/octave high pass filter on the mid/high horns.
Put a 4.7uF capacitor in series with the horn and a 0.6 mH inductor in parallel with the horn.
4.7 fd Monacor MKP Capacitor
0.60 mH Air Cored Inductor
See what the sound balance is like before worrying about an L pad.
If attenuation is your problem as will be protection, take a leaf out of the Eminence book and place a 24volt 10Watt light bulb in series with the horn, after your crossover. When the power is low, the bulb is cold and low resistance. As it gets louder, the filament gets hotter and warmer until the resistance increases to protect the horn.
Cheap, fool proof and simple.
Cheap, fool proof and simple.
'Bettered', that is interesting. I might just try the cheap crossover for now and see where that goes, plus I dont have as much experience of tweaking loudspeakers as you guys. I ordered the larger horn as well, hopefully it'll give me the kind of result I'm looking for.
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And they seem to know how to produce some serious sound from live equipment so not a bad tip. I've actually seen this bulb trick elsewhere but still researching it myself, but no doubt it seems like a very neat method of protection. Im just sticking to the basic crossover set up for now.
Great tips on the capacitors though, those will be noted not just for now but for future also. Got a very old set of epos loudspeakers here as well which have never had their capacitors changed, but do they actually need it, they still work. Those are speakers with their bass wired direct as well and are one of my favourite sounding designs, so I am keen on the minimalist crossover approach.
I'd be really surprised if that cheap horn sounds better than the original bullet tweeter you have, I was going to suggest you not bother but was too late.
And speaking of bullet tweeters, I suspect that the original design of these speakers utilized a "fullrange" woofer driver with the bullet adding sparkle on the topend which means it should be crossed at 5-8khz and no lower. Do you still have the original crossovers? If so can you post some pics of them? Or maybe tell us what model the speakers are, maybe there are some specs online we can lookup.
That is a very good point actually, that has got me thinking, so thanks.
No, I don't have the original crossovers anymore. The speakers when I got them were pretty much fried, and the components of each were slightly different anyway as one was active and the other just meant to be a passive slave off the active I think. Everything was basically burnt out and I gutted the speakers to what they are now, the electronics were scrapped, unfortunately, but they were in a bad state.
It was a while back since I stripped them and I can't even remember what they were wired like. They did have quite large potentiometers on them as well not sure if it was for the overall level of the slave and master. I basically took all the switches and pots out as those were seriously corroded as well.
What you say about them being bass straight wired could well have been the case with the treble unit for added sparkle. I have been using them like that with the piezo and it worked ok, sounded better running instruments/vocals through them than they did with a CD for instance though, that would really show the limits of those cheap p horns. The bullets will have more clarity if I can get them set up in the speakers correctly again.
Separately, I have found some other spare crossovers here which are 2.5khz 250 watt, which I played with yesterday with the bullets. I found Using the crossover on the bass perhaps does take a little bit away from it so I may just go back to straight wiring it, as you suggested. The bullet tweeter doesn't project as much as I thought it may but you could well be right perhaps its just for extra sparkle after all.
I do really like the idea of trying those larger horns though. From memory even some of the very old designs I used to use with that larger type horn I enjoyed the sound of. Gave a real honky type projected treble which I found quite entertaining and raw with certain music and could scream at you quite ferociously when played at louder levels. Plus if I get those other crossovers they'll bring more horn sound into the mix as they cross over a little lower 4.5khz. That's my theory anyway
How/if I get the balance the drivers yet is another thing.I bought one horn, for now, to see how it goes. It's just a bit of fun this project and it's not costing me a huge fortune, and maybe I'll get more enjoyment/life out of these old speakers yet.
I see those larger horns can cost around 130 on Thomann, but they may be better quality than the ones I'm looking at. I see the bullets can cost near the £70 mark as well from them. I just paid a couple of pound for new diaphragms and they're fine now.
Monacor MHD 152 – Thomann UK
that's 130 for horns each, yet they sell complete speakers for similar money, or even less.
the box PA 110 – Thomann UK
My speakers are Peavey ES12A and M originally, these are photos after I gutted them though, with the cheaper piezo horns in.
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The first point that has been missed entirely by the above post is power. The Peavey in that box is at best a 100wrms driver. Power wise, you are well in the clear as long as you don't do anything silly. Secondly, you have NO idea of the response of that woofer and it could have a horrendous upper frequency response.
For safety and possibly the 'best' result, try eminences off the shelf PXB2:3k5 3.5khz crossover. Its decent quality and won't be overpowered by anything that the woofer would survive. 12db low pass and 18db high with tweeter protection. Also has a spot to put a resistor in for HF attenuation
Secondly, the 2.2 uf cap is not as bad as it sounds, the rolloff is very high(good) but shallow. It could potentially work with the mid range hump many of the small horns get while providing ENOUGH protection to work with that rather low power 12" driver. You won't kill a 1" horn in a 100w cab when used with a 2.2uf cap unless you run HF tones at full volume all day.
In all honesty though, without ANY testing whatsoever, your result will be average unless super lucky. You'd probably be better off using an eminence coax 12 with its own purpose designed crossover(all off the shelf)
You could also use a fane or eminence dual cone etc.
For safety and possibly the 'best' result, try eminences off the shelf PXB2:3k5 3.5khz crossover. Its decent quality and won't be overpowered by anything that the woofer would survive. 12db low pass and 18db high with tweeter protection. Also has a spot to put a resistor in for HF attenuation
Secondly, the 2.2 uf cap is not as bad as it sounds, the rolloff is very high(good) but shallow. It could potentially work with the mid range hump many of the small horns get while providing ENOUGH protection to work with that rather low power 12" driver. You won't kill a 1" horn in a 100w cab when used with a 2.2uf cap unless you run HF tones at full volume all day.
In all honesty though, without ANY testing whatsoever, your result will be average unless super lucky. You'd probably be better off using an eminence coax 12 with its own purpose designed crossover(all off the shelf)
You could also use a fane or eminence dual cone etc.
hmm, thanks, all noted. I'll have a play here and see how things go. Those crossovers you mention do look decent, I will consider those. I've built speaker boxes and speakers before in various forms auto and home, but I've never really always loved the process or always the results either. These are just something I'm playing with at the moment. From an instrument point of view (guitars and processors plugged in) even with the replacement cheap piezo horns in they sounded really good and seriously rocked loud with a large PA behind them, however listening to some music from a decent source shows they are not great sounding speakers, yet the big cones (big ish anyway) can shift a bit of air, so just seeing if they can take a bit of tweaking. As I said its a bit of DIY fun thats all, perhaps without going too much with spending. And it keeping some old gear alive and that.
I've been using Beyma FD250 crossovers with 500W RMS speakers for wedding events and so far no issues. The capacitors on the crossovers are rated 200V and the coils are over 1.5 sqmm wire, so they withstand abuse when needed. They even work with P7000 Yamaha amps without problems. The first ones were rated 100V and one time I burned a capacitor and a Compression driver coil. These have 3 attenuation settings and horn correction EQ for the HF drivers. Mine are working with the highest attenuation setting.
Very neat crossover those and with the attenuation settings and horn correction EQ for the HF drivers. But just a quick search shows that theyre not cheap, getting up to a off the shelf PA speaker price, which is all designed to work well together, like they already sell in Thomann. Buying those for the little bit extra would probably be better than me trying to refurbish my old dogs, but then again what fun would that be in this throw away society. Plus these newer speakers a mostly ABS, plastic now or whatever, sure they weigh a lot less and makes transportation a lot easier, but I still think you cant beat wood.
Beyma FD250 professional passive crossover (per pair) for sale | Bax Music
You were pretty spot on with both counts here I think Conanski.
The new horn arrived today and I did a bit of fiddling with the spare crossover I already had here. First of all the new large horn did sound worse than the bullet IMO, at least with the crossover I have at 4.5khz, despite its high db figure 102db at 1w/1m it was actually a fair bit quieter than the Fostex bullets that I have, but it sounded kind of naff as well, a bit nearer to the piezo sound even, but not as plasticity.
Finally the other thing I did was straight wired the bass bypassing the crossover for the bass and just using it for the tweeter as a high pass filter. And it is the best the speakers sounded so far.
I do have more crossovers coming tomorrow these do go lower a 2.5khz, not a huge difference to the 4.5s but there'll be a bit more going to the horn, whether it'll be a good thing or not is another matter.
Big disappointment the big mid/treble though, none of the big honky projection I was expecting, but then again the crossovers I have don't exactly bring much mid into play either, they are more toward the sparkle end.
So are you thinking then that crossing the bullets I have now any lower maybe not such a good idea?
To be honest what I heard today Im pretty much tempted to solder and seal them all up and just use them as they are. It sounds pretty good actually for a mouldy old PA speaker, but I might not be able to resist trying the other crossovers tomorrow
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