Conference hips::uk_audioo

    The lack of bass is probably because of the boxes your front speakers
    are in.  I suspect your old car had the door speakers mounted actually
    in the door which gave a good bass isolation between the front and
    rear of the speaker.
    
    Lots of people have poor sound in their cars because of the way
    the car manufacterers have placed the speakers.  Door speakers mounted
    near the floor are somewhat less than optimal for balanced sound
    because of the directional quality of higher frequency sound and
    the fact that your ears aren't mounted near your ankles or knees!
    
    This is certainly true in my Daimler, all four speakers are mounted
    in the doors, but the position for the rear passengers is far better
    than for the front.
    
    You could try placing speakers higher up in the front or if your
    rear speakers are powerful enough and you don't carry rear passengers,
    putting most or all of the music through them.
    
    If your car is basically noisy then I suggest headphones and throwing
    your speakers away.  But really, a firm in Oxford sells a kit for
    soundproofing your car to get rid of engine and road noise, it is
    quite cheap and easy to fit (they say) and that would improve your
    sound immediately.
    
    When I went to get an audio system for my last car, a Jaguar, the
    person there said "you will want a powerful amplifier for a big
    posh car like that".  I replied that as the car was very quiet to
    drive (ie virtually no engine or road noise), I would not need a powerful
    system.  I went somewhere else then.  I changed the single unit
    door speakers for B&W two-way units and settled for a Pioneer 9080
    and ???? amplifier for the rear speakers.  Power output was about
    25W max but I was deafened at half volume-ish because my ears were
    not being shut down by the noise of the car.  Jaguars are heavy
    because of all the sound proofing in them.  Their bodies are almost
    as rubbish as other cars and they bend in accidents but they are
    QUIET!
    
    Nick.
    
    
    
    

    Hello Nick,
    
    I was toying with mounting the front speakers into the door frame,
    but I don't think there is enough space behind them because of the
    door check strap, when the door is shut.
    
    My car is fairly quiet (compared to those that I have used), although
    the exhaust note is usually apparent.  There is a quiet resonance
    from around the instruments when the engine is cold.  I have no
    doubt that it would sound like a fairground to you after the daimler!
    
    I might just try lining the plastic boxes (in which the front speakers
    are mounted) with plastic metal to strengthen things.  The tray
    is held on the door with a simple catch and a single PK screw.
                            
    Here is the problem:    
                            
    			| �- Door frame
    			|       
    		    ----|   
   Plastic box -�   |\- |            
    		    | \    �- Speaker         
    		    |  |||      
    		    |  ||| () �- Door check strap, 
    		    | /          when door closed                  
    		    |/- |            
    		    ----|             
                        |    
                             

    As you can see, if the speaker were mounted in the door, it would
    intefere with the check strap. 8-(

    Rob.

 On a somewhat less hi-fi note, does anyone know what the SW B line does on
Pioneer amps, or what assetion level the MUTE line is ? 

 What I am trying to do is to connect a personal CD player up to it so that I
can use that in the car.

		 Alan
		~~~~~~

    SW B - No idea
    MUTE - 0 volt = music
           5 volt = mute'd

     Hi,
     
     The front soundstage in my car is currently created by separate midrange 
     and tweeters.  The oval midranges mounted high at the front of the doors 
     and the tweeters atop of the dash.  The sound is excellent, don't get me 
     wrong...
     
     However, I feel the tweeters are a little too sensitive, the result as an 
     extreemely open and bright sound.  I would like to lower their output by 
     a couple of db.
     
     I am looking to perhaps use a resistor in series in the tweeter feed.
     
     The detail:
     The tweeters are Kenwood KFC-T101's (rated 4 ohms).  The midranges are 
     Infinity 462 (4x6 inch) Single-cone full range speakers (rated also 4 
     ohms).  The signal to these is split low from high by a Realistic 2-way 
     crossover, at around 4khz (although that is for 8 ohm speakers).  
     
     These are driven by a Kenwood KAC-720 amplifier, rated at 70w 
     peak/channel and 35w RMS into both channels for 0.5% THD.  
     
     
     Any suggestions to the rating and quality of components would be 
     appreciated.  Can one get higher quality resistors to reduce the 
     unavoidable increased degredation of the signal to the tweeters?  What 
     rating 1ohm, 2ohms?
     
     I don't think that I need worry about the amp having to drive a difficult 
     load, it's a little beast (you should see the big beast for the back!).
     
     I am willing to run with educated guesses and to try it and see.
     
     Thanks in advance,
     Robert.
     
     p.s. I will be entering into the Sound-Off competition at GTI 
     International, at the Road And Research Centre, Crowthorn on 11th May.  
     Wonder how much better the best will be?

     To answer my own note.  I gained help from the AUDIO_ENGINEERING 
     conference in the states (topic 66).
     
     The 8-Ohm crossovers do not function quite correctly when used with 
     mainly 4-Ohm car speakers.  Hence a dip in sensitivity mid-range, leaving 
     the treble sounding harsh.
     
     Solution:
     Bought a pair of Kenwood 4-Ohm 4khz crossovers - �24.

    
    Robert, have you got any info/catalogues about in-car speaker
    networks?  I've just ripped the dash off my Volkswagen (they bolt
    things together too well if you ask me!) to install a new aerial and
    alarm and figured while the dash and trim is off I'll fit a new stereo 
    to save me doing it all over again in a few weeks.
    
    Any help on where to get speakers/crossovers/fairly reasonably priced
    amps would be appreciated.  Don't know how much I want to spend at the
    minute, not sure on the prices of seperate units...could do with a CD,
    but that can wait 'til later if I can only afford a tape/tuner now. 
    Might be tempted to go for a CD/tuner, but I'd really like a tape as
    well.
    
    Any ideas as to the best set-up?  It's a Santana I'm fitting it in, so
    there's plenty of space for things and the cabin's quite big.  The
    doors are a bit limiting as there isn't much room between the panels
    and the internal trim.
    
    Sorry I've asked a lot of stuff in here, I'm just a bit lost as to
    where to find stuff!
    
    Chris.
                                            

     Yo Chris!
     
     The weary spender's guide to starting a really good Car Hi-Fi...
     I am no expert, but have read quite a bit and spent the last 3 years (60+ 
     hours effort!) working on it.  Make lots of mistakes too!
     
     
     Speakers - Tweeters:
     I heard some KEF tweeters in a Cavalier demo car at GTI International w/e 
     before last.  They were really well installed, are only about 1 inch in 
     external diameter.  They sounded really clear, yet not harsh.  
     
     Although the salesman did mention that 'acoustic damping film' had been 
     put over them because they were quite bright.   ??????
     
     They are �55 a pair.  My Kenwood KFC-T101's were �60 a pair.  You can pay 
     up to �120+ for tweeters, but these both are really good, low cost (in 
     relation) examples.  
     
     Assuming you'll go for a 2-way front setup...  Am not really up on 
     Midranges or small bass drivers which you could put in the front.  Steer 
     clear of anything smaller than 4 inches in diameter, 6 inches would sound 
     great in the front.  Do love my Infinity 4x6  @�40  although not much 
     bass from them.  

     I'd just get some good front speakers first.  Don't be tempted to buy a 
     few rubbish speakers for the back just to complete things.  The rear can 
     be concerned with only really low (sub) bass, and a little rear fill.  
     Otherwise you get sound originating from behind you, as I currently get 
     to a small extent.
          
     Crossovers:
     The Kenwood HPX-400 4-ohm crossovers are well made.  They cost �22 for a 
     pair to run my front speakers.  The crossover is at 4khz, remember to 
     match this frequency to the mid and tweeter you choose.  Belive me it's a 
     lot better when you get it right!
     
     Source:
     Hmm, there are so many good Front ends, the sort of price for modest, 
     good equipment:
     	  	CD/Tuner      	�300    Check out Sony's kit.
     	  	Radio/Cassette	�150-�400
     	  				Kenwood have a well reviewed �150 
     	  				deck.
     	  	Radio/Cassette/CD Changer
     	  			�400-�600
     	  				Sony make techtonic front ends.
     	  				Alpine are in the high end of the 
     	  				market but reputed to sound superb.
     
     Kenwood currently appear to have the edge on Cassette quality over all 
     but Alpine, who are close.  Unless you go over �400 for a Radio/Cassette.
     Kenwood's CD's are of Sony manufacture with their markup already added, 
     check out Sony and Alpine.
     
     To audition, I recommend Sextons Car Audio.  They have a great attitude, 
     average prices, and give suberb after-sales help.  � hour from Reading at 
     47 Western Avenue, Woodley.  Tel. (0734) 442049
     
     Installation:
     They do installations, but I guess you will be doing it yourself over 
     paying �20 per hour labour.  I haven't seen the quality of their 
     workmanship, but expect it to be average to good.  If you are looking for 
     Mercedes standard then Car Audio Labs member dealers are the ticket, but 
     at a very large price premium.
     
     If you do it yourself, get some decent speaker cable from the start- 
     @�1.50/m  it'll cost �25 for the whole car, but it will be worth it.  
     Also get a good power supply line to the set.
     
     Don't know the Sanata's doors or rear shelf.  Generally mounting into 
     Medium Density Fiberboard (MDF) smooths the sound and gives a good tight 
     base for the speakers (therefore solid, tight bass).  It's cheap from 
     places like Hicks.  Thickness is very important with large (over 6 inch) 
     speakers - go for about 3/4 inch thickness.  You can cover with Acoustic 
     cloth to hide your investment!
     
     Think for at least a week where the front speakers can go.  Let me know 
     if you want to know more about placement.
     
     Think to the future then looking for a head unit, look for a pre-out line 
     output to drive amps in future.  You will get a removable quick-release 
     cage with most head-units these days.
     
     Gosh, I'm out of time....
     What do you think?
     
     Cheers,
     Robert.
     
p.s. How's the grant.

    
    Ta very much Robert, knew you wouldn't let me down, guess I'll have to
    pay you a visit next time I'm in DP... =;*)
    
    I've got to consider *very* carefully what I'm gonna fit and how, 'cos
    the stuff I get's got to last a long time!  The grant next year won't
    help matters, but while I've got a bit of cash to spend on the car I
    will!  (I'm a Poly student on an industrial placement for those
    unfamiliar with my habits etc... =;*)  ).
    
    Thanks again for your help, I'll get back soon.
    
    Chris.

Hi,

I recently changed my Kenwood Radio/Cassette to a new Denon model.  My 
Kenwood had a round 5-pin din connector for the line output.  The Denon has 
two pairs of phono sockets, one for the front, one for the rear.

In order to connect this to my pair of amps, I required some phono leads.  
On being quoted about �35 for a pair of 2 metre shielded interconnects, I 
decided to visit the local Maplins shop and make my own.

I bought what looked like their best shielded OFC copper signal cable, 
priced high at �1 per metre.  This has a pair of wires shielded inside a 
full sleeve and braiding.   Each end I terminated with a soldered gold 
plated phono plug.

On hearing the new front end, I have nNOT been impressed by the bass 
response.  It's sort of there, but not as it was with my old Kenwood 
source.  Pitch stability and clarity is quite improved to a really 
impressive level.   This is merely a source upgrade, and my amp and 
speakers have not been changed.


Now this Denon 707R costs over �300, has no on-board amps for that price, 
and received a very good review for it's tape ablility.  It also sounded 
outstandinly good at a recent car hi-fi exhibition (In-Car 92).

I am returning the unit to the dealer tomorrow because the auto-reverse 
mechanism seems to have the head slightly out of alignment when playing in 
the forward direction.  I will see if the new unit sounds any different 
with respect to low bass.

I really am suspecting my home made signal lines.   Especially since I read 
the following in the manuals:

    Kenwood KRC-545L	Audio preout level/impedance 300mV/180 ohms
    Denon DCR-707R	Audio preout volt               1V/10 k ohms

       Both manual specs state cassette response is 40hz-16khz, pretty     
       ordinary for a decent in-car unit.

I have balanced the input trim on each amp to allow for the difference in 
input signal level.  Could the impedence of the cable I have used 
be a problem, altering the sound?

Is there a standard impedance, to which all line level signal cable will be 
close to?   Would you attempt to obtain any other cable ir just swallow and 
pay the man and hope 1.5m will reach under the seats.

Thanks,
Robert.

    What is the input impedance of the power amp?
    
    Dave

It is 10 k ohms, so would appear to match the Denon.

What do you think?

Rob.

    The Denon's o/p impedance is fairly high at 10K, compared to the
    Kenwood's. This may not be a problem in terms of load mismatching, but
    it does make the system interconnect dependent. This is because the
    ratios between cable reactances to input and ouput impedances are large
    compared to the ratio between just input and output impedance. It
    therefore tends to load the signal more than the power amp, and because
    it is frequency dependent you get the results you are hearing.
    
    You need to either change the dash unit for one�� with a lower o/p
    impedance, or experiment with cables.
    
    Have fun.
    
    Dave