Adding a tweeter? How?

[Moos3h]

Hi folks,

I run two Ashdown MAG cabinets with upgraded neo Eminence speakers and love 'em. Except sometimes, I just feel I'd like that super high-end you get from a tweeter.

Can I buy a tweeter and lob it in? Or am I going to need to faff with a crossover and such? I thought that there are some tweeters either had them built in, or didn't need them, due to their design?

Any help and recommendations would be GREAT!

Thanks,
James

[icastle]

It's piezo tweeters you need to be looking at if you want to avoid adding a crossover.

[Bill Fitzmaurice]

As the old saying goes, if you have to ask...
In any event midrange drivers work far better than tweeters, which don't start working until an octave higher than you want, and continue to operate an octave higher than you need. Either way the installation is simple if you know what you're doing, but might as well be rocket science if you don't.

[stevie]

As icastle says, adding a single piezo is by far the easiest way to go - and shouldn't cost you more than a fiver. It's not going to be a perfect solution because it probably won't be quite loud enough, but it will give you that bit of tizz you are after. Just stick one on the top of your cab to see what you think. You'll need to try it wired in phase and out of phase to see which is louder.
Adding a proper tweeter is a lot more complicated, easier to get wrong, and costs more.

Edited April 5, 2012 by stevie

[Moos3h]

Thanks Stevie - that was a really helpful answer.

Could/would you recommend a particular one (Piezo)?

[stevie]

Sorry, I haven't dealt with piezos for years, although I'm aware that there are quite big differences in the brands. The Fitzmaurice cab builders use them a lot and will no doubt be able to advise you. Dave Perry could be your man.

[brensabre79]

I used to have a tweeter box that i used with my old Acoustic 1x18" 4 piezo tweeters in it. It was 70s technology though, and not really a great solution, not sure if these are still around anyway.
Like Bill says mid range would probably be better. I wouldn't go hacking up your Ashdown cabs either. Your best option would be to look at getting a new cab that better suits your needs to be honest - perhaps one that uses the Eminence Neo drivers plus a midrange and tweeter if you need it.
Or if you're brave you could look at building something that uses the Eminence drivers you have, a crossover and a tweeter. You'll need a cabinet design that suits the speakers though or you'll be in a world of nastiness!

[Moos3h]

Thanks - I'm thinking I'll do what Stevie says and find a piezo tweeter, wire it up outside the cab and see if I like it. If I do, I'll chuck it in the cab.

If it doesn't sound right to my ear then it's only a few quid lost.

I've contemplated changing cabs but in all other respects (size, weight, overall tone) I'm very happy with these.

[stevie]

Alternatively, you could also have a word with Ashdown. If they did a tweetered version of the cab they will no doubt be happy to sell you a tweeter and x-over for you to fit yourself. That way, it would still look like an original Ashdown cab. Unlike most, Ashdown spares prices are quite reasonable.

[Moos3h]

That's a genius idea! Will see if I can do that

[Bill Fitzmaurice]

[quote name='Moos3h' timestamp='1333621364' post='1604305']
Thanks - I'm thinking I'll do what Stevie says and find a piezo tweeter, wire it up outside the cab and see if I like it.
[/quote]It's not that simple. First off you need at least two piezos series wired to withstand the voltage swing, a single unit won't do it. And while piezos are advertised as not needing a crossover that's not actually the case, for professional use they most definitely require filtering, and there are no 'off the shelf' filters for piezos, you must construct one yourself.
True many manufacturers do just toss in a single unfiltered piezo, but only because that's the cheapest way, not because it's the right way.
The right way to get better high frequency response without tearing into your cabs is the fEarful headcase.
http://greenboy.us/fEARful/

[stevie]

Paddy stopped cutting the hedge as the big car drew up beside him and an English visitor enquired:
"Could you tell me the way to Balbriggan, please?" Paddy wiped his brow.

"Certainly, sor. If you take the first road to the left.... no still that wouldn't do..... drive on for about four miles then turn left at the crossroads...... no that wouldn't do either."
Paddy scratched his head thoughtfully. "You know, sor, if I was going to Balbriggan I wouldn't start from here at all."

Edited April 5, 2012 by stevie

[Phil Starr]

[quote name='Bill Fitzmaurice' timestamp='1333629354' post='1604514']
It's not that simple. First off you need at least two piezos series wired to withstand the voltage swing, a single unit won't do it. And while piezos are advertised as not needing a crossover that's not actually the case, for professional use they most definitely require filtering, and there are no 'off the shelf' filters for piezos, you must construct one yourself.
True many manufacturers do just toss in a single unfiltered piezo, but only because that's the cheapest way, not because it's the right way.
The right way to get better high frequency response without tearing into your cabs is the fEarful headcase.
[url="http://greenboy.us/fEARful/"]http://greenboy.us/fEARful/[/url]
[/quote]

"logical advice gets you in a whirl"

I wouldn't disagree with the factual basis of anything Bill has said but with his conclusion that it isn't worth making the attempt. Piezo's aren't great, They usually lack sensitivity, their frequency response isn't very flat and crossovers need a lot of knowledge not least because the manufacturers don't give out much/any information so you have to test the things to know things like their capacitance.

But and it is a big but they are cheap as chips and you don't need a crossover for them to work.

For less than a fiver you can try out a couple and see what it sounds like. They vary but will handle between 20 and about 35V which equates to 50-150W so two in series is a good precaution.

If all you want is a bit of tizz then this is a cheap way of getting it, I'd put them in a separate box, no need to spoil your cab.

The Ashdown route is going to sound better and Bill is right that if you want to change the sound of your bass markedly then look to a mid-range unit, Though this is going to pose much more in the way of design problems than a couple of piezos.

[bertbass]

One of these will let you know if it's a road that you want to go down and if no one else bids pretty cheap too.

http://www.ebay.co.uk/itm/One-BLUE-SOUNDLAB-PIEZO-SPEAKERS-TOP-BOX-2x-HORNS-4x-TWEETERS-new-/230766555536?pt=UK_ConElec_SpeakersPASystems_RL&hash=item35bac23190

[stevie]

On the piezo front, my web researches indicate that you need a unit with a CTS (Motorola) piezo element. It's not always easy to tell, as there are a lot of copies around. The Monacor MPT range seems to use them, as do these ones from CPC, which seem to be quite popular (and cheap): [url="http://cpc.farnell.com/_/mpt-001/piezo-tweeter/dp/LS02371."]http://cpc.farnell.c...ter/dp/LS02371.[/url]
There's no harm in using two, but because a bass guitar produces very little energy at these frequencies (unless you play like Markus Miller all the time), you are very unlikely to overload a single tweeter. Two would be more sensitive though.

Edited April 6, 2012 by stevie

[Phil Starr]

You could also try one of these [url="http://www.bluearan.co.uk/index.php?id=SKT902490&browsemode=category"]http://www.bluearan.co.uk/index.php?id=SKT902490&browsemode=category[/url] which unusually do have a L/C filter built in. They'll need a horn which you can buy for about £5 but they are standard screw in units. They don't need a series resistor like many piezos and an 8ohm resistor in series will give you a 3dB cut in sensitivity if there is too much fizz. They have the advantage of going a little lower as well.

[MoonBassAlpha]

If there's too much treble in a tweeter loaded cab, why don't folks just turn down the treble on the amp a bit? Seriously?

[guybrush threepwood]

Sorry to potentially hijack the thread, but I've been thinking about knocking up a cheap tweeter box using piezos, and I'm just wondering about the wiring... I'd wire 2 in series, as my amp is 525W, but I've heard about adding a 20-30 ohm resistor in series to kill any frequencies above 20kHz that could potentially damage the piezo. Does anyone know what power would this resistor need to be?

[Phil Starr]

[quote name='guybrush threepwood' timestamp='1333839910' post='1607333']
Sorry to potentially hijack the thread, but I've been thinking about knocking up a cheap tweeter box using piezos, and I'm just wondering about the wiring... I'd wire 2 in series, as my amp is 525W, but I've heard about adding a 20-30 ohm resistor in series to kill any frequencies above 20kHz that could potentially damage the piezo. Does anyone know what power would this resistor need to be?
[/quote]
The resistor is about protecting the amp rather than the piezo . They present a capacitative load to the amp which makes some of them oscillate and their impedance falls with increasing frequency which some don't cope with either. I use 5watt resistors and haven't lost one yet. Some piezos have the resistor built in. Check with the supplier if you can.

[guybrush threepwood]

Ok, that's great, cheers. So (one more thing) if I was to connect up a couple of [url="http://www.pyleaudio.com/sku/PSN1165"]these[/url], would the wiring go like this? ...+ connector -> resistor -> tweeter -> resistor -> tweeter -> - connector ?

[Phil Starr]

You only need a single resistor and as it is in series it doesn't matter where it goes. The big resistors are heavy enough to break a soldered connection so use a cable tie to fix it to something convenient, usually one of the tweeters. Make sure the connection between tweeters is + to - . plus to tip minus to earth if you are using a jack socket.

+ connector to resistor to +tweeter- to +tweeter- to -connector is one way

[guybrush threepwood]

That's great, cheers Phil