CDM1550 - external and internal speaker

[g8tzl2004]

If I connect an external speaker to a CDM1550 does the internal speaker automatically switch off?

I've checked the archives - there are some reports that the CDM1550 will automatcally detect the external speaker and disconnect the internal speaker. However, other comments indicate that you need to manually disconnect the internal speaker rather than using CPS to select an external or internal speaker.

Any thoughts?

Thanks

[Thomas]

With some CDM1250's I've owned in the past connecting an external speaker does not disable the internal speaker. Perhaps some of the newer radios operate differently in this regard. Anyway it's pretty easy open the radio and disconnect to speaker if need be. I kinda liked those CDM internal speakers, they have a nice soeund to them and are loud enough for most mobile applications.

[g8tzl2004]

Thanks Thomas.

Anybody know if later firmware CDM's can automatically disable the internal speaker when you connect an external speaker?

I've done more archive searching and read some comments that if you use a very low impedence external speaker the internal speaker may appear to switch off but actually its still working but very quiet??

I find I like the CDM RX audio better if you switch off pre-emphasis. Its much easier to resolve really weak DX signals which sound slightly muffled with pre-emphasis on!!! At least switching off pre-emphasis works ..unlike the HT1250 which is unusable without pre-emphsis enabled!!

[Bill_G]

I don't see how firmware would affect the accy port of a CDM. There is no mechanical switching or looped wire there. Nothing to make or break when a plug is inserted.

[escomm]

No, an external speaker will not disable in the internal speaker. To disable the internal speaker you must disconnect it inside the control head, HTH

[RFguy]

I suspect people "think" that the internal speaker is disconnected as the large external speaker is such low impedance compared to the internal one that most of the audio is comes from the external speaker. It makes it sound like the internal speaker is no longer operating.

[g8tzl2004]

Thanks for all the feedback.

I also just want to check that its 100% OK to use a 16 way accessory plug in the 20 way socket? Pins 1 and 16 are already wired up with an original Moto speaker.

[escomm]

Thanks for all the feedback.

I also just want to check that its 100% OK to use a 16 way accessory plug in the 20 way socket? Pins 1 and 16 are already wired up with an original Moto speaker.

yes, no problem. the outer 4 pins on the 20 pin connector are 17-20 on the layout.

[sataraid1]

I wish the CDMs had a simple jumper on the back like older radios. Disassembling the control head to switch the speaker is a pain, considering how flimsy they are and how poorly they fit together.

[g8tzl2004]

UPDATE: I connected the external speaker which works great. As RFguy indicated, it sounds like the internal speaker is disconnected as the external speaker is always much louder. If you put the external speaker under a pillow, you can then just hear the internal speaker!!

To be honest, I don't think I really need to disable the internal speaker as it sounds like its disconnected anyway!!

[SteveC0625]

UPDATE: I connected the external speaker which works great. As RFguy indicated, it sounds like the internal speaker is disconnected as the external speaker is always much louder. If you put the external speaker under a pillow, you can then just hear the internal speaker!!

To be honest, I don't think I really need to disable the internal speaker as it sounds like its disconnected anyway!!

I found the same thing with a CDM1250. I added an unamplified external speaker in the garage area of our ambulance station. The CDM is in the office. With the volume set just right for the office environment, the volume out in the garage is much louder, but just about right for that larger and noisier area.