radio speakers for Astro Spectra

[rangerfourever]

Guys any thoughts on a good speaker for 800 trunk Astro Spectras....the "butcher" shop that put in our squad radios used Galls specials that are great for my cell phone kit but have terrible audio on our trunk system. I know we can get Spectra or MCS speakers but cost is a factor any thoughts

thanks dave

[misawatech]

I'm getting into this with our fire guys now. They want to know if I can install normal car stereo speaker in the chiefs vehicle so they are hidden in the rear hatch.

In addition to the cable problem with openeing and closing the hatch but I can probably figure that out. I am more concerned that car stereo speakers, normally rated at 70 or more watts, cannot be driven by the astro. I'm trying to fgure out the normal output of the audio now. I'm also looking for some speakers that I can try before saying it will work.

I think it is a safe bet that cars stereo speakers cannot be driven by the astro. If I find out more I will post

Fred

[Pj]

Guys any thoughts on a good speaker for 800 trunk Astro Spectras....the "butcher" shop that put in our squad radios used Galls specials that are great for my cell phone kit but have terrible audio on our trunk system. I know we can get Spectra or MCS speakers but cost is a factor any thoughts

thanks dave

I'd find out why (first) they are not using the Motorola speakers. I'd hate for you guys to get the audio PA circuts fried from a custom hack job and Moto refusing to honor a flat rate price in sending them in for repair.

I'm getting into this with our fire guys now. They want to know if I can install normal car stereo speaker in the chiefs vehicle so they are hidden in the rear hatch.

In addition to the cable problem with openeing and closing the hatch but I can probably figure that out. I am more concerned that car stereo speakers, normally rated at 70 or more watts, cannot be driven by the astro. I'm trying to fgure out the normal output of the audio now. I'm also looking for some speakers that I can try before saying it will work.

I think it is a safe bet that cars stereo speakers cannot be driven by the astro. If I find out more I will post

I'd tell them tough. It has been done, but I think guys have used isolation transformers and the such. You can get smaller speakers that will fit in tighter places, but if they are overly concerned about astetices in a working field vehicle, they have too much time on their hands.

But, its their equipment...if they want stuff to be done in a not-so-good way, have them sign off on it.

[misawatech]

I'd tell them tough. It has been done, but I think guys have used isolation transformers and the such. You can get smaller speakers that will fit in tighter places, but if they are overly concerned about astetices in a working field vehicle, they have too much time on their hands.

But, its their equipment...if they want stuff to be done in a not-so-good way, have them sign off on it.

I agree wholeheartedly. It is not necessarily a field vehicle that they are concerned with. It is our chief 1 and chief 2 vehicles that they want to pretty up.

They're not concerned about the space. They know they can find speakers for the provided spaces. They want something that can be hidden in these compartments and to the best of my knowledge Moto doesn't make a recessed speaker.

My whole concern, as you stated, is I can probably make it work but then what happens in a few months when the circuits fry? If we go forward I am definitely going to have them agree to modifications.

I was thinking of trying it on an old spectra first just to see if the radio can drive the car speakers

You know I was just thinking. Don't the standard Moto speakers have everything mounted in the faceplate? I wonder now if I could just mount that section in the hatch area just as if it was a car stereo speaker. For that matter, if the space it the same as most of your door speakers I should be able to take out the guts of a Moto speaker and install it into the door/hatch. I'm going to have to go chekc this out tomorrow.

[HumHead]

I'll try to answer some of this, for the benefit of both posters without hijacking the original subject of this thread too much further.

Most /\/\ speakers have a nominal 8 ohm impedance (there are a few 4 ohm). You can connect pretty much any speaker, including a car stereo speaker, a /\/\ speaker, or anything else, without any worry as long as it presents the appropriate impedance to the amp, and does not cause either side of the amp's ouput to be pulled to ground.

Using a speaker with a higher impedance will not harm the radios's audio PA, but will cause much lower audio output levels because the amp will deliver less current to the higher impedance load. Using too low of an impedance (including a dead short) will draw too much current and could toast the amp.

The power rating on a speaker says nothing about how much power it takes to drive it. The power rating merely specifies the amount of current that the speaker's voice coill can safely handle before the wire in the coil melts. (Given how fast and loose car and home audio manufacturers play with their specs, their numbers are always a little suspect anyhow.) The actual speaker sensitivity is usually provided as the dB SPL level produced at 1 meter when the speaker is driven with 1 watt. Good luck finding that spec for /\/\ or most car stereo speakers.

Bottom line- you are fine using any speaker you want, as long as you get the correct impedance and do not short it to ground. However, you may not be very happy with the way that it sounds. One of the reasons that /\/\'s speakers work so well is because they sound so bad They are designed strictly for the range of the human voice. They do not reproduce high frequencies very well, and the bass is non-existent. If you try to use a full-range "hi-fi" type speaker, you will probably find the sound "muddy" and find that you will have to turn it up louder in order to understand it, particularly over road noise. You may also start to notice PL hum and DPL buzz that were not reproduced by the "low-fi" communications speakers.

You are correct about the construction of the /\/\ speakers. I have panel mounted them before by taking the two halves of the housing apart and sandwiching a panel, with an appropriate cutout, between them. Depending on the thickness of the panel, you may need longer screws to reassemeble the enclosure. Resist the urge to just leave the back cover off, your intelligibility will suffer if you do.

[EVModules]

I'm with Humhead.

With creativity, you can try looking "up", yes mount them in the headliner using the sandwish technique but look first. On some vehicles, there's not enough space between the liner and the roof while others have plenty. Definitely don't mount where the backside touches the metal roof. We've been using the smaller speaker (part # unknown) from an outfit from Arizona and it really works for space issues. Sometimes "B" pillars were used too!

Other than that, been hooking up to factory AM/FM radio speakers for years whenever a dept requested it. We used the front speakers, one for each 2-way radio and adjusted the fader to all rear. No problems reported on audio quality.

[Will]

The Spectra and Astro Spectra have the same speaker requirements.

8 ohms, 10 watt minimum power handling.
The factory speakers are 8 ohm, 20 watt rating.
The speaker leads MUST NOT be grounded anywhere, or you will burn out the audio IC in the Spectra.

Look at the HSN8145, HSN 9008, HSN9326 type speakers, I am not sure which one is 8 ohms.

Also see this topic http://batboard.batlabs.com/viewtopic.php?t=65555