FM vs AM volume/reception

[Hullabaloo]

Does anyone else find a volume level drop between FM and AM in their cars? When I switch from FM to AM i usually need to increase the volume by a reasonable amount to reach the same loudness (such that turning back to FM with same level is way too loud).

Possible causes? DC5S head unit or inglass antenna?

At first I thought maybe it was a characteristic of inglass antennas but my friend's s15 also has factory head unit and inglass antenna and he doesn't suffer from any volume drop between FM and AM (we tested cars next to each other using same radio stations).

[aaronng]

Characteristic of AM radio. While AM radio has less fidelity than FM, when reception is low, you only lose volume with AM rather than audio quality with FM.

[Hullabaloo]

Characteristic of AM radio. While AM radio has less fidelity than FM, when reception is low, you only lose volume with AM rather than audio quality with FM.

I wouldn't have thought much of it until when sitting in my friends s15 and he showed me the volume level was exactly the same.

[aaronng]

I wouldn't have thought much of it until when sitting in my friends s15 and he showed me the volume level was exactly the same.
If your DC5S has an internal antenna while his S15 has an externally mounted one, then of course your DC5S' AM reception will be poorer (less volume).

[Zdster]

If your DC5S has an internal antenna while his S15 has an externally mounted one, then of course your DC5S' AM reception will be poorer (less volume).

Just a thought/question. Can they put a booster on the antenna (like they can do on tv aerials) to boost the signal/volume?

[aaronng]

Just a thought/question. Can they put a booster on the antenna (like they can do on tv aerials) to boost the signal/volume?
You can. But it would be the same as just increasing the volume. Since AM radio works by using amplitude modulation (hence AM), you're not getting a clearer signal using a booster, but only a louder signal.

[Hullabaloo]

his S15 has in-glass antenna as well. After doing some looking around on the net I've come to think that this problem is quite common and there are several reasons why this might be the case.

1) The 'volume' of the AM station is affected by signal strength at your receiver, far more than FM stations.

2) The two systems use largely seperate electronics in your receiver and differences in these can cause level variations.

3) There is a lot more compression applied by FM music stations than by AM talkback stations and this will give the impression that the FM is louder, because the average level of the signal is greater, due to compression.

Since his car and mine were parked next to each other I would dismiss 1) and 3) and think that maybe his electronics has a booster for just AM maybe?

Also, I don't find that the quality of the AM signal is better or worse in his compared to mine.

[aaronng]

Since his car and mine were parked next to each other I would dismiss 1) and 3) and think that maybe his electronics has a booster for just AM maybe?

Could be. I've compared an Astra and my Euro. Granted the Astra had an external antenna but my AM volume was about 1/2 to 3/4 of the FM volume while the Astra's are the same for both AM and FM.

[Hullabaloo]

Update: I've found out that radios use "antenna trimmers" to boost AM signals. Generally these can be adjusted. Does anyone know how I could find out if/where it would be on my dc5s? Would this be a question to post in the integra forum or audio forum?

[ACTI0NMAN-1]

i find i get better AM reception with my hids on than FM

[Eclipsor]

Update: I've found out that radios use "antenna trimmers" to boost AM signals. Generally these can be adjusted. Does anyone know how I could find out if/where it would be on my dc5s? Would this be a question to post in the integra forum or audio forum?

It may simply be a better/worse tuner design. The range for the quality of parts and circuit design is huge for radio tuners. You can build one at home with a $10 Dick Smith kit. Or spend as much as you want to a certain degree. Better oscillator design, better designed amp stages and the quality of the individual parts used.

Possibly whoever designed the dc5's radio just didn't match the gain very well on the am and fm circuits.

I doubt your dc5 has any sort of adjustability on the tuner. At least externally. If there is any adjustabilty it is probably set internally at the factory. Most of it is probably digital anyway.

My fairly cheapo JVC headunit has adjustable volume offset for all of the sources.