Amplifier Design - Extended Range Speakers

Bob Kagy · From: Lafayette, CO USA

There are a lot of good threads running on amps. I'd like to raise another issue.

I wonder why we don't see any products that supplement the big, woofer-like speakers with mid-range and hi-frequency tweeter speakers.

When I listen to CD's that have steel players (who may have recorded direct or with a miked amp), I listen through hi-fi equipment including extended range speakers, and of course the steels sound great.

Also, with the little experimentation I've done, speaker cabinets with extended range setups (woofer + mid-range + tweeter) seem, in my opinion, to give much more pleasing tone.

A poster some months ago referenced Bill Lawrence's website where an experiment was described in which Bill had added an inexpensive Radio Shack speaker with extended range to a steel guitar amp (I forget which), and seemed to be pleased with the results.

So, there are some obvious cost and directionality issues involved, but why not extended range speaker setups? In either combo amps or extension speaker cabs?

Opinions, comments?

Joe E · From: Houston Texas

Bob,

I agree that the PSG world could use a little revamping in the speaker dept. Awhile back I asked opinions on favorite spkr combonations. Only 1 or two mentioned multi range configurations. I'm in the process of designing some real Steel spkr cabs. I think the PSG world is ready for a great sounding cab. A few thoughts to date: A single cab, with a 15" and a 10", but in different portions of the cab. Completely seperate from each other. The other is a piezo type horn to pick up all the harmonics that are lost in the cone of a 15" spkr. A actual horn would be to bright for most tastes. With all these incorperated into one cabinet, a very full and clean sound SHOULD occure. I'm still doing some computeing to get the right combination. Oh yeah weight become a real factor.

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Joe

"76" Fender Artist S-10

[This message was edited by Joe E on 02 March 2000 at 02:08 PM.]

[This message was edited by Joe E on 02 March 2000 at 02:09 PM.]

DON ENGLE · From: INDPLS IN USA

Joe E about your real steel spkrs
i built a set with a 3 way crossover and put a volume pot on the piazzo tweeter to bring down the highs to a liveable level they
work great for me i play in stereo
quite often and on stage you can really feel the difference. on the weight theory i use 7/16 osb plywood covered with carpet from menards i also use aluminum cone
speakers i believe that makes alot
of difference i know it makes them lighter Don

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Joe E · From: Houston Texas

Great input. The piezo shouldn't need a cross over, and actually I'm experimenting the idea without crossovers first. The design of actual speaker dictates alot of where the drop offs are. EX: a 15" speaker may not effieciently produce freq's higher than 1000hz. And the sound above just dies out. The 10" speaker will actually go up to maybe 2500hz, but will only go down to 250hz. Now these freq's vary from model to model.

I'm interested in the overall smoothness of the cabinet. And how much overlap the components will have. Especially from 250hz to 800 or 1000hz.

What was the freq's of the crossovers and what was the order (1st, 2nd, 4th,Butterworth?)or 6, 12, 18db

[This message was edited by Joe E on 03 March 2000 at 06:44 AM.]

[This message was edited by Joe E on 03 March 2000 at 07:48 AM.]

Jack Stoner · From: Kansas City, MO

I have a pair of ported stereo system speakers I built using a D-120F (from a Fender Twin) and a 3" tweeter in each speaker. I've used them, at home, with my MosValve 500 amp as a practice amp til I got my 12" BW speakers built. I had to really boost the lows and cut the highs on my Transtube Fex to get anywhere close to a decent sound out of them. I didn't listen real close but it sounded like everything was coming out of the D120-F's. I know the tweeters work as there is sound coming out of them when the speakers are connected to my stereo system.

Although the speakers were designed for a stereo system (using JBL design specs) they do have musical instrument speakers in them. I'd have to be desperate to use them on a job with my steel.

Joe E · From: Houston Texas

With the design I'm discussing, the peizo or tweeter is there only to pick up the harmonics of the strings being played. The overtones or offsprings of the actual notes. You may not actually hear specific sounds as much as, it should add sparkle without getting to bright. They use this alot in acoustic guitar amps. But really anything that relies on the body of the instrument heavily for the sound will benefit.

Also the cabinet must be "tuned" to the speaker being used. Usually somewhere around 40-60hz. THis is done by changing the port or baffle size. The larger the port the lower the cabinet is tuned for. This will need to match the speaker specks. Also if the tweeter being used is of the paper varity, it will not have very much throw to it. Where as a peizo will carry quite some distance.

This should be great in a club or in a studio that mic's with two mic setup. One close and one back 12-18".

Bill Rowlett · From: Russellville, AR, USA

I put piezo's in my Session 500 years ago to help with 6-string playing. It didn't do anything for the steel tone and just made the normal amp hiss worse.

Bill

Joe E · From: Houston Texas

Your right about it picking up hiss. I don't use Peavy Amps but if there is any his this would bring it out. Maybe the newer PV's are a little cleaner. Not sure though. I try to use a power amp that when connected to the speaker and turned on with no input but the volume turned all the way up, you don't hear anything or very little.

As you add components you will fine the noisy components. Usually it's the FX units. (Try the bypass switch)

Rich Paton · From: Santa Maria, CA.,

Any JBL D series or F-series (With the aluminum center cap) has a rising output sensitivity with increasing frequency, which extends the upper usable freq., albeit at the cost of smoothness.

I once had a setup with a D130 15" and a pair of D110 " JBL's, the 10" units in their own open back cab.
The D110H's were in series with each other (Zt=16 ohm) and this load was in parallel with the D130H (Z=8 ohms) for a Zt of 5.33 ohms.

As a different approach, one lacking all the quirks of a crossover network and system interactions, what about using a smaller amp (8" or 10" speaker), along with the 15" black widow/Nashville 400 type setup most of you would probably be using? The smaller amp's eq controls would handle the matching to the bigger amp/speaker.

[This message was edited by Rich Paton on 04 March 2000 at 02:54 AM.]

[This message was edited by Rich Paton on 04 March 2000 at 02:55 AM.]

[This message was edited by Rich Paton on 04 March 2000 at 02:56 AM.]

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