Saturday, February 16, 2008

Crash testing with Napa DAV315

Crash testing with Napa DAV315
version blogspot original article here in Geocities

Following my interest in MP3 technology the last years and the big list in MP3 in songs recorded throughout the years, the information read from many magazines and e-newsletters and web pages , I have finally decided that a MP3CD player could be the ideal solution for me to replace my walkman and my other CD player. This was also the result after a recent purchase of a CD recorder whose main use will be at first for any necessary future backup at first as well as for collecting this material just in MP3CDs

The S/N of the model is DB02007083 manufactured April 2001

As you know I like to make inspections of any interesting gadgets. And here is an exhaustive analysis for the Napa 315. And much better as I recently bought a CD recorder that helped much in makling a line of Cds for the testing and normal playback of my big collection of more than 2500 songs from tapes , Cds and SW recordings .

Before of all just to notice : Although volume is OK for headphones with number s till 6-7 , when connecting to a HIFI , the level of 19 connected to the headphones socket is very low . line out is also much lower more than 6 decibels lower and still adjustable by the vol level. ( possbly below the 15 uV though 200 uV are the standards on all audio equipment !! )
316.jpg (31272 bytes)

Part 1 - appearance
This model has a very nice 'trendy' Appearance supplied in a plastic firm pack and includes a mains power supply with the uncommon level of 5 VDC of half width than any other commercial power supply I have ever seen , two NimH batteries , a belt , a stereo jack to 2 RCA for connecting to hi-fi and earphones
4 buttons are from the left side acting having slightly different functions between CD and MPCD operation the and 4 buttons from the right side having a a button lock , two for digital volume and one for various modes ( ie acting as menu )
Battery charger
This means that CD player has a built in battery charger requiring to abt 15 hrs to fully charge the batteries. It is required to charge in full. Their nominal storage is 1.6 Ah . LCD also shows the battery status with 3 level bars . I t seems that the adapter is still charging while NAPA 315 is playing. Actually the voltage as measured with multimeter shown 4,68 VDC and must be connected to mains supply if plug is connected to the unit , or the unit is NOT working ..
Also in case of low bateries the unit plays the song and stopsd after rebuffering

Instruction guide - acessories

Its instruction guide uses very small letters. I suppose they use fonts of 6 picas and smaller in the case of the gray notices. Although for me is a bit OK with the gray notices to read a bit difficult , I think that a little bigger font could be better for reading
The belt is relatively big for the player's size and quite wide and thick . It mostly reminds usage of …. professional photo cameras

The headphones are very typical with nothing impressive Just a little treble from abrt3.5 kHz and over , regarding to my Kenwood DPC183 open air headphoneswhiu ch i use as standard headphones also in DXing.

Part 2 Operation - buttons playlists

Using the buttons
When playing any Audio CD the search skip buttons act as FW and REW When playing MP files they act as file search , unless [DIR] option from mode is used

Now for the [MODE] button . It works like a menu with many options show in brief and how buttons are used
RPT  (repeat function )
/ one (repeat continuously same song)    next  prev work OK
/ all  (again from start)      next  prev work OK
/ dir  (repeat only what is from this directory)   next  prev work OK
/ int  (play only the first 10 secs )     next  prev work OK
/ rnd  (random play and stop at end )    next : next random  prev; NO
/ rnd all(random from all directories)    next : next random  prev; NO
/ rnd dir (random from this directory only )   next : next random  prev; NO 

E (equalizer)
/ cls  (classic music)
/ pop  (pop music )
/ jaz  (jazz music)
/ rck  (rock) They are spectrum analyzed by software and info shown at end of this file 
File / dir (sequential selection of files or by directory ) 

Now for the LCD . When operating it shows if the CD used is a AuCD or MPCD and even (undocumented!) VCD. At left down shows the serial number of the song, as it does not show any ID3tag or even a filename,which is a feature only in the next model 516, and the time elapsed. As also other reposrts refer 315 does not have a backlight I m not interested in it as i always use it near to a fluorescent lamp.

It claims to be capable to support directory searching, CDR/W disc and multi-session and it is tryue . See later about this
I did not tried , but as documented it can make a playlist of maximum of 32 tracks

Part 3 MP3 usage
Incorect loading of MP3 CD
The unit displays Err 3 . I do not know the code but it seems to load the Cd again ( and press a little more)
File numbering and sorting - possibly the first most important feature
Here is something regarding the file numbreiung
315 uses the way a directory sorting uses. This is exactly what a dir *.mp3 /s under DOS can show I have seen that it has a direct relationship to which buning program has been used.
For example with usage of Nero ( Mode 1 and MOde 2) and Easy CD 3 or 5 give dirferent results:
More clearly
Nero MOde 1      mode 2      Easy Cd
0-9     0-9    0-9
A-Z    A-Z caps all   a-Z case insensitive

Also in case of subdirectories the sequence of sorting goes this way:
and so on
Maximum nmber of tracks recognized
I also verify the documented maximum number of 630 counted tracks in a CD having exactly 1000 MP3s all made under 16 kHz sampling rate. ( total recognized time 45.49 hrs!) Documentation shows also in case of 10 directoriues the numbers pfrecognized MP3 clips can lower to 620 At first it was pretty good to recognize the list of 290 files of a total CD-A time of 72:48 in 12 seconds (MPs of 15 hrs total time !)
Playback of MP3s
In all cases , the unit first sees it as cd then idetifies if ti is a MP3 Cd or VCD then in case of MP3 Cd tries top count the numbers of MP3 files ( and tales about 5-15 secs for this) then starts to paly the first song with always at the preset volume of 19 .
The FFW and REW work only for file searching rather than searching inside the track
Here you will find a series of observations and mysterious conditions All recordings are made with Nero
- Crop of ends !!! If a music file does not have an end with silence , the player will crop about 0.3-0.4 secs from it ( and possibly caounter will roll )
- VBR and constant rate while playing a VBR song 25% of 6:25 mins length the counter in many stances stopped for a few secs or minutes untill showing the end of the song
- IN many cases isaw that at the end of the songs of rate of 96 kb the counter was rolling too fast This especially happens when using Trimmer MP3 trim to trim out the ends of a song
-One also peculiar case : During random song playback , epecially if number diference is too high , the unit seems to hang up. .This problem is most significant when burning is set to TAO ( track at once) , but onDAO ( disk at once) the problem still happendss especially if unit is only battery operated. The motor spins veryfast , just recognizes the song but ddoes not start playback.
- ECD 5 : Counter neer shown the exact number of MP3 files in included in the CD.
I do not know what is really the problem but ECD5 seems to be problematic especially for the MP3 Only as a typical computer CD is recognized in full

Bit rates (tech)
Using the older tactic for MP3 testing , as shown on the specialized page , I re-used same files to check the ability of the NAPA player to playback them. Here are the results

-Constant rate
320 250 192 160 128 112 96 80 64 56 48 40 32 28 20 18 16 8/11 8/8 .
From these standards only the latest two were not recognized by the unit just the time counter rolls fast till end. See at the end of this paragpah for more.

- VBR 5 scales per Xing . Counter was rolling normally.
- steps of 10% as per MM5 Both ways have been heard perfectly
- a tone of 1000 Hz for auudio level check .more for this later
- fake MP3 from a .wav file ! Tough all programs hung , program did try its best to play the file as cratches and hisses .Stopped finally but not hung
- test audio with 8 bit resolution at various bit rates . All files olayed OK with the same audio, even soem older files shown a diferent dynamic audio range while playing on Winamp
- new MP3 plus (128 ) mode also played OK but with the 64 kb rate
- 8/8 and 8/11 modes shown many peculialrities. BY instances the unit played them well , by otrher instances the unit did not pleyd them, but just counter was rolling very fast.
-unit produces high frequency hiss for rates lower than 40 kb gradually increasing as rates are lowered

WMA and RA, are not recognized . Could like to see something later to recognize both formats !

It plays normally in multi session . However it seems to have a problem when the new session is in the root directory and previous sessions are in directories and also in cases when buffer underrun has been happened. ( tghough still the unit can paly the CD tll the bad sector)

In a few cases when new files are on root directory, the unit tries to recognize th CD , starts to play the first by letter and after 5 secs it stops playing ( hung)

This hanging found also in some ogther cases esp ewhen the file is at the end of a doirectory

Antishock and buffer NEW

Buffer: the unit has a 120 sec buffer as ESP checked as when the unit re-reads the CD( rebufering) . I have checked with 96 112 and 128 kb files for the moment and found that rebufering can happen 116 secs from start of song for the 128 kb rate and every 116 secs to restart reading CD . For 112 and 96 kb the times to 're-bufer' are 130 and 150 ( instead of 160) secs respectively .

Antishock and car usage :When drivign in a good quality asphalt roads there is not a ny problem. However as in Greece many roads are very old or remade , when driving over harsh asphalt roads with 80 km /hr or more , antishock mechanism can shut off the unit after 1-4 rebufferings . I have found that using a small face towel the problem can fully be solved .Just fold the towel and put the CD unit with three levels of folded towel

Antishock and buffer

Buffer: the unit has a 120 sec buffer as ESP checked as when the unit re-reads the CD( rebufering) . I have checked with 96 112 and 128 kb files for the moment and found that rebufering can happen 116 secs from start of song for the 128 kb rate and every 116 secs to restart reading CD . For 112 and 96 kb the times to 're-bufer' are 130 and 150 ( instead of 160) secs respectively .

Antishock and car usage :When drivign in a good quality asphalt roads there is not a ny problem. However as in Greece many roads are very old or remade , when driving over harsh asphalt roads with 80 km /hr or more , antishock mechanism can shut off the unit after 1-4 rebufferings . I have found that using a small face towel the problem can fully be solved .Just fold the towel and put the CD unit with three levels of folded towel

Other modes

CD audio and related features:

As about playback of different Cd types this already has been discussed. I t plays all the types - originals and computer copies , without any problem
A default operation when using CD is the120 sec antishock protection and can be disabled by the mode button . ESP is also shown in the LCD
IN contrast MP3 has this facility built in

Support of CD-A formats and models
As a multisession , multi type reader , it plays all the Cd ytpes , even the types that computer drives and CD players do not 100% support !

Example 1 : INTENSO CDs are not supported on my 52x drive. The NAPA player did support it very well
Example 2 . Recorded a 20 track CD-A from various kinds of music and different formats (MP3 and WMA) with the use of the bundled Easy CD 5 and 'CD text' and with various speeds on NONAME (bulk) CDs . The result has been tested in Napa , two Cd players and our HI-FI and here are the results
Nero has been lent for this purpose only.

ASKA NERO TAO 10x # + + +
Bulk ECD5 DAO 8 x # - - +
Bulk ECD5 Dao 6 x # - - +
Bulk ECD5 dao 4x # - + +
Bulk NERO DAO 8 x buffer underun
Bulk NERO DAO 4 buffer underrun

Philips CDA ECD3 +/# +/# + +
Intenso ECD3 + # + +

ASKA was the best CD used for the moment ( 10 x as standard)
TAO=track at once , DAO= disk at once ECD = Easy CD creator ,prg bundled with

Notices :
Aiwa shown mechanical jitter/problems when trying to identify the disks, nearly in all the cases except Philips recorded at 4x. At most cases it had to 'wait' for 10 secs to read the sectors., then counting tracks and starting after a while to play tracks . In many cases denied to work

Kenw 1( DPC 183) is my walkman It immediately read the ASKA CD even if is recorded at so high speed , though older recordings from a friend with ECD 3 shown two very bad points of 'skipping' ( unable to read ) and 'shifting' ( next sector)
Kenw2 is another walkman used for the test, It shown 100 % accurate readings from all 'problematic' Cds per DPC183 walkman
NAPA read all these systems without problems

The CD I used shows 3 directories a CDI a VCD and a MpegAV with the real data with .dat shown instead of .mpg or .avi
The VCD I have is an album of Andy a very good hit Chinese singer and audio used is matrix encoded ( ie L+ R and L-R are heard instead of pure L/R.)
Is this the Chinese standard?
Have not other VCDs to test
Just for reference this VCD is played exactly as a classical audio CD with the CD rolling continuously once it is played
The FFW abd BCK buttons of CD work here as track change
No antishock info is shown on the LCD during this mode

Playback on Multisession , mixed CD and VCD

Again both programs ( Nero and ECD 5 ) have been used with various results shown here :( and too many cds have been burned for this)
And soemthing other. In case of a damaged CD or dead points on its surface, the unit can show the serial song number but most times canot play the song (irregular counter time , irregular sounds and hang ion) . In this case you can select the next track

Nero with closed session worked perfectly on NAPA
Nero at multisession : NAPA found all directories on multi session CD and played them well ( in contrast to ECD5)

MP3 only 2 sessions: 214 out of 258 MP3 songs have been shown , the 2nd session track was not recognized!
Mixed CD with ECD5 : CD-A tracks were not recognized only MP files have been counted by player but could not play them ( just show 00.00)
Newer session over it: still no playback
ECD5 with MP files only: again nothing

Original albums
Mixed cd and VCD ( avi): VCD shown at the LCD of player, the CD rolls continuously , the CDA tracks are shown, but nothing more happens ….'
Video CD : (list of files on root, video files in directory as .dat ) :song were recognized and played well
MP3 Mag CD the MP3 files have not been found by the player ( MP3 files were in sub directory )


Volume and outputs

The Player uses a digital volume with 32 steps
After CD starts to play , the player uses the preset volume set of 19 ( of a total of 32steps ) which is too high in a quiet environment
At same environment with normalized tracks or MP files the best volume set is 4-5

IN contrast when connecting to a HIFI, the volume must be set to the predetermined level and use the ear jack ( 19) instead of line out total output will be very low
Line out: Its level is much lower and is adjustable (!!!) by the volume control at 6.5 db lower . It is something I dislike because line out must always be fixed level

Playback of MP3 rates below 40kbit shows a hiss re-generation audible especially at the lowest volume levels ( 1-5)

Audio levels for 1 kHz sinus tone /-6 db MP3 audio analyzing software from the ear output . For the line output please subtract 6.5 db

0 60 Noise Floor
1 48
2 43
3 38,3
4 33,6
5 29,9
6 27
7 25
8 23
9 21
10 19
11 18
12 17
13 16
14 15
15 14
16 13
17 12
18 11
19 10
20 9
21 8
22 7
23 6
24 5
25 4
26 3
27 2
28 1
29 0
30 1
31 2
32 3

Equalizer and audio response
As shown above there are 4 equalizer modes: classic, pop jazz and rock
Tested with a freeware computer spectrum analyzer program and have seen the following results with a white noise file as referred above :

FLAT -7 0
-12 12000
-22 21900

CLASSIC -8 <400 span="">
-12 4000
-15.5 13000
-16.3 14000
-19.2 21000

POP -12 1800
-16 14000
14.5 14200
-16.4 20700
-26 22000

JAZZ -11 4000
-15 10000
-17 10800
-21 2000

ROCK -10 250
-14.5 1000
-12.5 4000
-17 20600
-32 22450

Testing the random numbering with 258 MP files
Try1: 001 202 134 184 186 018 143 118 174
Try2: 001 110 104 005 217 158 137 238 210
Try3: 001 020 027 239 251 229 138 083 094
Try4: 001 248 025 239 253 170 126 231 012

Therefore there is not any standard randomization


As shown with the above tests , the NAPA 315 seem to be a very good CDA, VCD and MP3 Player except very few peculiar cases.

IN general I m very impressed with it and the MP3 ability to exceed too muchof the time of any CD or tape player without changing tapes or CDs As for example with the MPCD refered at the start of this web page, with 290 songs, recorded at 96 kbit, had a total of 15h 10 minutes of total playback, 630 MB of space used or 72:48 Cd time !

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