# Building speakers with vintage drivers and horns



## tanchiro58 (Aug 4, 2008)

Hello Everyone,

I am Newbie in this forum and planning to build my own speakers for two channel as well as HT. I also have on hand three pairs of vintage drivers (two pairs 12 inches Stephen Trusonic and a pair of Pioneer 12 inches coaxial driver) and a pair of JBL LE175 horns. They all have 16 ohms. 

My questions are based on what I have should I build a pair of Open Baffle speakers (I need to specifically say that the drivers would be in a closed baffle except the pair of horns and midrange JBL LE5-2s) or what is your suggestion? Any help and instruction would be appreciated.

Many thanks,
Tan


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## BoomieMCT (Dec 11, 2006)

Do you have T-S parameters for these drivers or any means to test them?


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## tanchiro58 (Aug 4, 2008)

Hi BoomieMCT,

What do you mean by T-S parameters? :scratch: Is that the DCR of the woofer for example? 

Thanks,
Tan


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## BoomieMCT (Dec 11, 2006)

Thiele Small parameters. It is a way to compare drivers and estimate their performance in different enclosures. By no means comprehensive, it does let you answer some questions quickly.


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## JCD (Apr 20, 2006)

tanchiro58 said:


> Hi BoomieMCT,
> 
> What do you mean by T-S parameters? :scratch: Is that the DCR of the woofer for example?
> 
> ...


Wikipedia has a pretty good summary of what the T-S parameters are.. Linky Dinky.

Besides being able to draw some basic generalities about the sound of the driver, they also help to determine the ideal enclosure volume for the specific driver. So, if you're going to build some speakers using these drivers, you would REALLY need to know what these TS parameters are if you're going to build a non-open baffle system.

BTW, those JBL horns look to be pretty good purely based on the current market value for them. I'm seeing $800 for a pair (Link). I'd serious consider using those and some other high quality woofer for your system. I'd seriously consider finding some place to professionally recondition the drivers. Their magnets may need some recharging as well as some other "stuff". 

I also found this discussion on another forum discussing the driver. 

So, here comes the bad news -- it looks like you have an awesome driver, but designing and building a good speaker system from scratch can be a little difficult unless you've got some experience/patience/money/special equipment. To add to that, I've heard that horn systems can be more difficult to get right as well. I don't know why, just have seen it around. However, when they are done right, it's supposed to be magic.

What does this all mean? I don't know. Just throwing it out there.

JCD


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## tanchiro58 (Aug 4, 2008)

Hello JCD,

Thanks for your links.

I fully understand that I need T-S parameters to build a non-open baffle speakers. The problem is how to build the crossover and cabinets to match with those horns and drivers even though they have superior sound compared to conventional speakers nowadays. The truth is after listening to those vintage speakers I could not resist myself to have ideas how to build them. Therefore, I need more information of anyone who happens to collect and know them.

Many thanks,
Tan


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## JCD (Apr 20, 2006)

So, I may be a little confused about what you're looking for at this point, but I'll tell you what I'd probably do if I found myself in your shoes.

Crossover -- go active. It takes all of the hard part out of designing a proper crossover and is from EVERYTHING I've read/seen vastly superior to passive crossovers. An analog purist would probably buy something from a brand like Ashly. Someone without this hang up might be inclined to get something like the Behringer DCX 2496. That piece of equipment is a tweekers paradise

Building the Box -- those horns don't need a box, but you will need the TS parameters for the other drivers. Those horns go fairly low, so I'd consider getting a fairly large woofer driver. Something in the 10", 12" or 15" range that goes up to ~1000Hz. Maybe something like this would do. If I was independently wealthy, I'd want to buy more than one. Building a box for this driver should be fairly straight forward since the TS parameters are readily available.

Once the box is built, all you'd have to do is mount the horn on top of the box and you should be good to go. 

This horn may not reach the upper octaves like you'd want, so you may want to procure something for that. It'd be better if you could find another horn to handle these upper octaves, but I'd probably try without first to see how it sounds. As we get older, we lose the ability to hear these octaves anyway.

By running down this path:

you won't have to buy a lot of the testing equipment (you'll still need some), 
you won't have to learn about how to design a crossover (trust me, that is one dark and arcane subject) and 
you'll end up with a good sounding system (most folks will always prefer an active crossover to a passive).

JCD


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## BoomieMCT (Dec 11, 2006)

I'll disagree with JCD's comment that active x-overs are "vastly superior". Better, yes, but much more costly and the difference is lost on most people. They are _immensly_ easier to set up though (that I agree 100%) compared to the "dark arts" of passive x-over design (which has a learning curve but is not quite arcane).

I'm still trying to understand exactly what you are asking. You listed a bunch of parts you have. Are you trying to find a way to use them to build a whole 2-channel speaker system? If you are a novice I would shy away from OB. OB is very cool but is harder to set up properly then enclosed systems. If you are dead-set on it (and I wouldn't blame you if you are) I would read as much material as you can on the subject on this board as well as going to audiocircle's OB forum and reading that. 

I would also agree that if you don't know what you are doing, don't mess with the design of the horns. Horns are tricky to make and you will, most likely, not be able to improve on them at this point. If you do go active you'd just need to make something that does the highs (where you opt to cut off the lows for the horns). Easy peasy - do it all sealed and forget about it.


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## tanchiro58 (Aug 4, 2008)

Hello JCD and BoomieMCT,

Thank you very much for your comments and suggestions.

The truth is I love very much the sound of vintage horns and speakers especially JBL, Jensen and Altec Lansing with Alnico magnets if they are set up right with my two channel system which I actually have own now.

BoomieMCT is right. The only way I can build is an enclosure baffle for the woofers but open baffle for the horns and midranges. The thing is how do I build the crossovers to take the speakers to the level of superior sounding.

Best, 
Tan


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## BoomieMCT (Dec 11, 2006)

tanchiro58 said:


> BoomieMCT is right. The only way I can build is an enclosure baffle for the woofers but *open baffle for the horns* and midranges. The thing is how do I build the crossovers to take the speakers to the level of superior sounding.


I'm not sure what you mean by the bolded part above. If it is a horn, it's not open baffle.


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## OB1 (May 3, 2009)

Do you guys have any idea where to get some vintage drivers? I have one Stephen tru sonic 112fr and would like to get a match of this, so i can build my open baffle.

Any ideas will be appreciated. Thanks


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## tanchiro58 (Aug 4, 2008)

BoomieMCT said:


> I'm not sure what you mean by the bolded part above. If it is a horn, it's not open baffle.


I went to CES this year and saw some open baffle design with a horn as a tweeter since vintage horn sound less brighter than conventional tweeter even the vintage tweeter like JBL 075 (bullet tweeter) or 077 tweeter.

My intention is a horn and midrange would be in a open baffle part and the woofer would build in the separate cabinet.

Thanks for your suggestion,
Tan


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## jackfish (Dec 27, 2006)

I'd try AudioKarma and Zilch specifically.


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## ampire (Nov 27, 2008)

JCD said:


> So, I may be a little confused about what you're looking for at this point, but I'll tell you what I'd probably do if I found myself in your shoes.
> 
> Crossover -- go active. It takes all of the hard part out of designing a proper crossover and is from EVERYTHING I've read/seen vastly superior to passive crossovers. An analog purist would probably buy something from a brand like Ashly. Someone without this hang up might be inclined to get something like the Behringer DCX 2496. That piece of equipment is a tweekers paradise
> 
> ...


Does that crossover need a amp for each driver? Or does it do high level? I am confused how it works.


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## JCD (Apr 20, 2006)

ampire said:


> Does that crossover need a amp for each driver? Or does it do high level? I am confused how it works.


Each speaker needs a different amp. Well, that's almost right -- each "channell" get's it's own amp. For example, in a typical 2 way MTM, you would need an amp for the tweeter and one amp for the mids.

That would mean that for a typical 2 way speaker, in a 2 channel system, you would need 4 channels of amplification instead of the normal 2 with a passive crossover. With a 3 way speaker, you would need 6 channels of amplification.

One benefit is that you can match the amps to the drivers being used. For example, you won't need a lot of power to amplify that horn, so you could easily go with a 20watt amp. In fact, I know someone who uses an 8watt SET tube amp for the HF horns in his Altec VOTT system. Because those horns are so efficient, and he went active (if I remember correctly, active provides an extra 3db over passive systems) he can hit ear exploding levels of sound.


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