multiple inputs into one speaker

topcop1833 · Post by **topcop1833** » Tue Jun 21, 2005 10:38 am

what would happen if say, 6 speaker phone ouputs were all wired to one speaker? again this speaker would be for output of speaker phones only, with the possiblilty of 2 or 3 lines "outputting" at the same time.

nmfire10 · Post by **nmfire10** » Tue Jun 21, 2005 10:51 am

Speakerphone like from a telephone, right?

topcop1833 · Post by **topcop1833** » Tue Jun 21, 2005 11:13 am

thebigphish · Post by **thebigphish** » Tue Jun 21, 2005 1:21 pm

zzzZAp. fizzle.

then the magic smoke would be out.

...and you'd be stuck replacing any of the cooked audio circuts on the phones.

Post by Pj » Tue Jun 21, 2005 4:59 pm

You basically need to balance all the lines coming in, and out to the speaker so you don't blow out everything.

Motorola actually has an audio transformer/combiner box for the spectra series radio's. I think list for it is around $600. However, a scamatic for it is available on MOL if you want to build one yourself. I think it supports upto 4 inputs to 1 speaker.

gws · Post by **gws** » Wed Jun 22, 2005 3:53 am

Check out http://www.bdenterprises.com/products/
They have a combiner that will take 6 speaker level inputs and produce an amplified single combined output.

Splat · Post by **Splat** » Wed Jun 22, 2005 5:31 am

PJ, I don't see that schematic. Got any type of model#? Thanks.

tvsjr · Post by **tvsjr** » Wed Jun 22, 2005 6:08 am

You might check these guys out too:
http://www.fleetradioproducts.com/products.htm

Cons: The owner showed up here and started "recommending" his product without bothering to mention that he was the owner of the company.

Pros: After I called him on it, he did apologize and revealed his true identity. I also talked to him and looked at his units at Hamcom (Arlington, TX), and they appear well-built and well-designed.

wa2zdy · Post by **wa2zdy** » Wed Jun 22, 2005 8:08 am

I looked at thopse websites and I admit, the fleet radio products units look good. A caveat though, especially for those folks here who are less technically inclined than others.

The manual they supply in pdf format discusses the need to be certain the speaker output sees a load no less than two ohms. That's fine, but then they tell the installer to use a VOM and measure the resistance of the total speaker load to determine that the load is indeed more than two ohms.

Ok, so who sees the problem with this?

As most of us know, the manual specifies the nominal impedance of the speaker(s), not the DC resistance of the coils. And the nominal impedance will NOT equal the DC resistance of the voice coil of a speaker. The DC resistance will likely be near zero ohms, or some percentage of an ohm. The nominal impedance is the average impedance at audio frequencies (AC, not DC.) (The impedance is nominal rather than specific as the specific impedance of the voice coil changes with frequency.) So this procedure in the manual is grossly incorrect.

Knowing the company puts something so incorrect in the manual - and this is basic AC vs DC theory - gives me pause as I try to decide if I want to order their product.

Caveat Emptor on this one.

tvsjr · Post by **tvsjr** » Wed Jun 22, 2005 9:09 am

Hey, ohms is ohms, right? You know you're discriminating against DC ohms...

I hadn't noticed that. Probably glossed over it (you know, automatic ******** filter in the brain). From what I could tell, the guy building/selling these is *not* the guy who did the actual design, which could account for some of the problems with the docs...

2112 · Post by **2112** » Wed Apr 05, 2006 9:47 pm

Can anyone advise if the Fleet Radio Products combiner (http://www.fleetradioproducts.com/4AMP-03B.htm) will work with a Uniden BC780xlt and two MCS2000's for inputs, and an amplified Motorola speaker and a Whelen SA314 (radio rebroadcast through a Cencom) for outputs?

Thanks...

pjb966 · Post by **pjb966** » Thu Apr 06, 2006 4:29 am

gws wrote:Check out http://www.bdenterprises.com/products/
They have a combiner that will take 6 speaker level inputs and produce an amplified single combined output.

This comes up NetMagic, Inc do you have any further info on this.

allcomm1 · Post by **allcomm1** » Thu Apr 06, 2006 7:34 am

We have used several of the Fleet Radio Amplifiers with positive results. They have been used with multiple MCS2000, ASTRO Spectra and XTL2500 and XTL5000 mobile radios. Seems like a well made product and the end users are happy with them so far.

gws · Post by **gws** » Fri Apr 07, 2006 2:03 am

http://www.bdenterprises.com/products/ appears to have gone out of business. I know they dropped the ba1 item last fall. The compnay was a small 1-2 man company. Looks like the fleet product will do what you need at a price similar to the ba1.

MSS-Dave · Post by **MSS-Dave** » Fri Apr 07, 2006 3:42 pm

Try here....

http://www.rdlnet.com/

I used the Stick-On brand of audio stuff at a major theme park here in Florida all over the place, one of which was a multi input mixer. They have CRAP loads of stuff for audio

Post by Pj » Fri Apr 07, 2006 8:42 pm

I thought that I had replied back in the day....I know it was posted in the ASTRO fourm... The scehmatic is under the ASTRO dual radio/dual receiver supplemental manuals.

2112 · Post by **2112** » Fri Apr 07, 2006 9:51 pm

2112 wrote:Can anyone advise if the Fleet Radio Products combiner (http://www.fleetradioproducts.com/4AMP-03B.htm) will work with a Uniden BC780xlt and two MCS2000's for inputs, and an amplified Motorola speaker and a Whelen SA314 (radio rebroadcast through a Cencom) for outputs?

Thanks...

I decided to take the the dive and picked one up. The gentleman that I spoke with was very helpful and professional, and provided a 10% discount because I happen to be a ham.

Will advise my findings...

aaknitt · Post by **aaknitt** » Wed Apr 12, 2006 8:12 am

If you want to roll your own check out the ARRL Handbook's "Expandable Headphone Mixer". I don't know if it's in the current edition, but I know it's in older copies. Might need a small amp on the output to drive a speaker but the basics are there...you can add as many inputs as you want.

Andy

2112 · Post by **2112** » Mon Apr 17, 2006 12:55 am

2112 wrote:
2112 wrote:Can anyone advise if the Fleet Radio Products combiner (http://www.fleetradioproducts.com/4AMP-03B.htm) will work with a Uniden BC780xlt and two MCS2000's for inputs, and an amplified Motorola speaker and a Whelen SA314 (radio rebroadcast through a Cencom) for outputs?

Thanks...
I decided to take the the dive and picked one up. The gentleman that I spoke with was very helpful and professional, and provided a 10% discount because I happen to be a ham.

Will advise my findings...

So, the combiner arrived quickly after ordering... a handsome, tidy, black affair that works very nicely with my setup. Very well-built and easy to work with. The only thing is that I had to switch out my amped Motorola speaker with a non-amped version. That's okay, though... the amp in the combiner more than handles my need for amplified speaker output.

Tech support was extremely helpful as well.