Tweeter/horn way too loud

[LITTLEWING]

I've never been a massive HF unit in a bass cab fan and my old style Ampeg BA-115 100 watt combo's one seems way too over the top in relation to the 15" speaker. I like to have the treble up to give my bass a full range of sound and then use the guitar's tone control to suit each song as required but it sounds like a wasp nest with a football match going on inside. Right now I've taken the positive wire off and disabled it so I can have the treble up full to get the voice I want without the nasty crisp packet in a cinema scenario.
Any ideas what I can do to either turn the unit up or down via a control or maybe fit a switch with say three settings to suit?

[JPJ]

Have a word with the chaps at Blue Aran. I'm sure they'll be able to recommend/supply a suitable attenuator that you can fit to tame the beast

[Bill Fitzmaurice]

Insert an LPad between the crossover and tweeter. Google it.

[LITTLEWING]

Thanks chaps, just emailed Bluearan. Catch a reply after the weekend I guess. I looked at a few things that Google threw up and so many scary things emerged like overheating L pads and in-line caps not doing much due to mind-numbing science involving high ohmages and stuff...got frightened and went to bed.

Also doesn't appear to have a crossover, the pos. and neg. come straight off the speaker terminals to the tweeter/horn.

Edited January 13, 2017 by LITTLEWING

[Dan Dare]

If no crossover, tweeter has to be a piezo. They're about the only ones that are immune to low frequencies and can be used in that way. They're also cheap 'n nasty in the main. I second Bill's suggestion, altough you may have to do a bit of experimenting to find the right capacitor/resistor values. Unless you're pushing serious current into it (which you won't with a low powered combo), you don't need to worry about overheating. Obviously, you need to use sensibly rated components - 100v or so.

[Bill Fitzmaurice]

If it's a piezo you can't use an LPad. Read this:
http://www.baysidenet.tv/catalog/pdf/piezo.pdf

Note that not all piezos are alike.

[LITTLEWING]

Cheers Bill, that article is most informative. Think I'll just leave the wire off. Lol !!!


I hate HF units with even more passion now......

[Bill Fitzmaurice]

There is a right way and a cheap way to load bass cabs with tweeters. Care to venture which method is the most commonly employed?

[Dan Dare]

[quote name='Bill Fitzmaurice' timestamp='1484345585' post='3214920']
If it's a piezo you can't use an LPad. Read this:
http://www.baysidenet.tv/catalog/pdf/piezo.pdf

Note that not all piezos are alike.
[/quote]

Didn't know that Bill. Thanks. May have been being unjustifiably cruel to piezos.

[Phil Starr]

Thanks for that link Bill, when I was experimenting with piezo's I had to work out the capacitance and impedances myself.

For the OP the capacitor resistor circuit does work and takes out some of the harshness. Start with a 5uF capacitor in series and a 10ohm resistor im parrallel with the tweeter.

I had some of the old Motorola piezos which sounded OK. Bill will know but I think CTS may have taken on the Motorola plant when they stopped production. They weren't widely available over here when I checked quite a few years back. The cheap Chinese made piezo's are definitely inferior both in sound and reliability. I decided in the end that a conventional horn driver and crossover were always going to sound better.

[Bill Fitzmaurice]

[quote name='Phil Starr' timestamp='1484409190' post='3215285']
I had some of the old Motorola piezos which sounded OK. Bill will know but I think CTS may have taken on the Motorola plant when they stopped production. They weren't widely available over here when I checked quite a few years back. The cheap Chinese made piezo's are definitely inferior both in sound and reliability. I decided in the end that a conventional horn driver and crossover were always going to sound better.
[/quote]Motorola piezos were dismissed back when they were the only game in town, to some extent rightfully so, because they were never properly employed. Motorola sold their piezo business to CTS, and they were still disrespected until a few years after CTS went out of business. That changed when NOS Motorola and CTS piezos started to command premium prices, often ten times that of the Chinese versions. Then the same people who had never endorsed piezos changed their tunes, and said that the NOS Motorola and CTS were fine but the Chinese brands were junk.
I still have some NOS Motorola and CTS on hand. Some Chinese brands, notably Goldwood, work better.

Piezos properly employed work just as good as compression drivers. But to get piezos to work well they must be used at least in pairs, as they lack the voltage capacity to be run singly at high volume. They also must have a real crossover, one that employs a resistor to offer the crossover a resistive load. That resistor can't be 8 ohms to use an off the shelf 8 ohm crossover, as the insertion loss is far too high. There's no off the shelf solution, it must be custom configured.

I have yet to see a single commercial manufacturer who properly employs piezos.