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Horrible feedback howling trying to set up DS02/DM02
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 Posted: Saturday Nov 5th, 2011 07:27 pm
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schford
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I am pulling my hair out :(

I just cannot get a decent volume at the gate without introducing horrible howling. I tried setting the trimmers on the DS02 but to get rid of the howling it ended up sooo quiet.

Then I tried the tuning - I set paramter 86 to 4 - but now the thing just howls at me :-(

I am giving up for the night - am I doing something wrong?

Stuart



 Posted: Sunday Nov 6th, 2011 05:47 am
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ident
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Are you hearing the intercom howling using Keypad to Door station, or local phone to Door station or Remote Phone to intercom?
If keypad, which keypad are you using, KP04, KT03 or KP03

What wires are you using for the cables to the Door station? and how far it is?

How far is the door station from the keypad (if you are using the keypad) If they are next to each other then there will be positve feedback between the two



 Posted: Sunday Nov 6th, 2011 03:40 pm
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schford
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Hi :-) Thanks again for the help.

The howling is local house phone to door station - that's the only one I have tried so far as that would be the one we mainly used I think.

The system is set up as follows - we have the main Comfort unit in our utility room. From there I have KA and KB and Mic out and Spk In on a pair of twisted each in a shielded CAT 6 UTP (the one with solid core) cable. This runs under the house for probably 10 to 15ms max and is then connected to some armoured solid CAT 6 cable. This runs under the drive and up into the garage where the KA and KB are connected to the SEM and the Mic ou and Spk in to the DM02. That cable is probably 8ms long.

The DM02 is connected to the DS02 via Shielded Cat 6 cable for 5 m this then connected to armoured CAT 6 which runs the last 4m to the Door Station.

Cheers

Stuart



 Posted: Sunday Nov 6th, 2011 03:56 pm
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schford
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After having a little play around with the rheostats on the back of the DS02 - I now have that at a reasonable volume (though still a little quiet but no howling but now cant hear it on the hosue phone lol :-)

I'm sure I am just missing something obvious.



 Posted: Sunday Nov 6th, 2011 04:05 pm
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schford
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Significant progress has been made :-) I wound back both the rheostats in the DS02 and have made most of the alterations in tuning - its not quite perfect but a bit more fiddling and I think I will be there :-)

Last edited on Sunday Nov 6th, 2011 04:15 pm by schford



 Posted: Sunday Nov 6th, 2011 04:39 pm
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schford
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Could someone explain the difference to me between (85)AFE KP MIC GAIN and (86)AFE KP SPK GAIN - I have read the manual about 4 times now - I think it means they both increase the volume at the Door Station - is that right?

With the Mic boosting it first then the SPK boosting it second?

Thanks

Stuart



 Posted: Sunday Nov 6th, 2011 05:22 pm
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schford
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Got it working perfectly - then screwed it into the back box and it howls - arrrrrr I am pulling my hair out :-)



 Posted: Monday Nov 7th, 2011 01:03 am
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The AFE KP MIC Gain increases the gain at the KP Mic (to get louder volume at the other end ie the DP)
The AFE DP SPK gain increases rge gain at the KP Speaker, so they arre completely different effects

You should not adjust these AFE KP and MIC gains as you  are not using  the KP to DP intercom, you are using Local Phone to DP

I am not sure which manual you have, the Tuning Parameters Adjustment Guide can be downloaded from http://www.cytech.biz/tuning_parameters_guide.html?category_id=99

I suggest you save your current settings and reload the original default Tune Parameters settings as these should work for Local Phone to Door station

Do File Import > Configuration Items  and select the default template def34.cct, then select Tuning Parameters.

Then fiddle with the trimmers on the DS02 to reduce any howling. If you find the volume low when listening to the phone you should reduce the volume of the phone to DP path (ie the DS02 Speaker trimmer) rather than increase the volume of the  DP to Phone path (DS02 Mic)  as the system will reduce volume to prevent howling

Keep the tuning parameters constant and adjust the DS02 trimmers so you avoid adjusting multiple things at the same time

The DS02 has its microphone in a rubber boot which helps provide accoustic isolation. make sure that is in place



 Posted: Monday Nov 7th, 2011 07:07 am
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schford
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Hi Ident :-)

Thanks for your help - again!

I think the manual is a little confusing it says I should change 85 and 86 - quote below!! Incidently the figures shown below seem to be wrong as well for range you can use. eg 83 will only go upto 7 and 84 can only be 3 or 4.


"Local Phone to KP/DP (Figure 2 and 3)
Local Phone AFE IN (Parameter 83) Range = 00 (min) 20 (max). Default 4
Local Phone AFE Out (Parameter 84) Range = 0 (max) to 4 (min) Default 4
KP/DP Mic AFE IN (Parameter 85) Range = 00 (min) 20 (max). Default 7
KP/DP Speaker AFE Out (Parameter 86). Range = 0 (max) to 4 (min) Default 2"

I'll reset it and start again - could you let me know how to check the rubber boot on the DS02 - what is that? I dont recall seeing a rubber boot.
Thanks :-)

Last edited on Monday Nov 7th, 2011 08:18 am by schford



 Posted: Friday Nov 11th, 2011 05:49 am
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The min and max values described in the document refer to the possible values but the software restricts them to a more limited range so that the extreme values which would not work cannot be programmed
The rubber boot for DS02 is actually enclosed so it would not be visible. I was thinking of DS01




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