Difficult to categorize this thread, but since most of the topic will be related to chipamps used on computer speaker kits this one seems most appropriate. The following question was directed to fas42 (Frank) on the Blowtorch thread. Frank has been the leading member (as far as I know) on upgrading the electronics of PC speaker kits to an unprecedented level and we have decided to open a new thread to openly discuss this topic. – If someone likes to get some background on Frank’s views just search his posts on the Blowtorch thread.
The following was the question addressed to Frank on the BT thread…
Frank,
After hearing many times of your experience with PC speakers I decided to give my sennheiser cans a rest and brought out a set of Pleomax S2-300B PC speakers (Samsung) and after a week of warming them they still didn’t sound good so decided to look inside the “plate” amp. It looks generally well done with all cable connections welded and the only thing it occur to me was adding a good Pana FC 100uf to the main filter and after a couple of weeks it’s sounding quite decent, albeit not to the level you describe. In fact I’ve just played the Oosten "Organ Symphony No 6" Widor you mentioned and did a credible rendition at a moderate level but no window shattering of course… but quite pleased up to this point.
I’m wondering what to do next, maybe changing all other caps for better ones? Better decoupling for the audio chip? Which would be your suggestion?
Antonio
The following was the question addressed to Frank on the BT thread…
Frank,
After hearing many times of your experience with PC speakers I decided to give my sennheiser cans a rest and brought out a set of Pleomax S2-300B PC speakers (Samsung) and after a week of warming them they still didn’t sound good so decided to look inside the “plate” amp. It looks generally well done with all cable connections welded and the only thing it occur to me was adding a good Pana FC 100uf to the main filter and after a couple of weeks it’s sounding quite decent, albeit not to the level you describe. In fact I’ve just played the Oosten "Organ Symphony No 6" Widor you mentioned and did a credible rendition at a moderate level but no window shattering of course… but quite pleased up to this point.
I’m wondering what to do next, maybe changing all other caps for better ones? Better decoupling for the audio chip? Which would be your suggestion?
Antonio
Good on you for doing that, Antonio - thanks!
In the middle of something else at the moment, give me a moment, will answer at length later,
. But in the meantime, could you elaborate on what the PC speakers are doing "wrong" compared to the headphones - where are they not up to scratch, being as specific as you can?
In the middle of something else at the moment, give me a moment, will answer at length later,
. But in the meantime, could you elaborate on what the PC speakers are doing "wrong" compared to the headphones - where are they not up to scratch, being as specific as you can?
I've had plenty of plays with cheap active speakers - take a look at some of the older posts on my blog (link over to the left). I started out by improving the grounding - rigorously imposing star earthing and separating out power grounds from signal ones.
Since then I've learned a bit about power supplies, so I'd move on to that, replace single reservoir caps with CLCLC (filtered) arrays of caps.
Since then I've learned a bit about power supplies, so I'd move on to that, replace single reservoir caps with CLCLC (filtered) arrays of caps.
Definitely all good points, I'll have a look to your blog, thanks for the input, will comment later.
Antonio
Well, I did a comparison between Pleomax (PM) and the phones (PH) which seemed like comparing apples and watermelons over the same Widor piece (WP), and of course they don’t share the same PS. PH in the other hand reach much lower like an octave or more. Let me say also that I hadn’t used the PH for at least a couple of months.
PM
Before testing with the PH I heard several times the WP over the PM being the last time more critically and my general opinion was that it sounded nice and musical but lacking in the lower end (which was expected) even thou some mashing was heard at the end of the first movement and other portions of the WP and a shade of noise some places. Came to think that I liked the midrange and upper MR.
Second run.- found that I had neglected the Bass control that comes with the PM and started to play with it a bit, first full tilt and that gave and exaggerated feel of bass and was not pleasant (quite mushy too) so I backed a bit at a time until I got a more balanced overall sound, mo better, and came nearer to the PH, but sometimes (depending on frequencies of the music) the upper mid came to interfere with the musical event.
PH
A different animal, overall more balanced and deeper on the soundstage less grunge and almost not at all mashed over the heavier passages (not necesarly LF), also very few instances of perceived noise but who knows if it was on the recording or glitches on the DTA and amplification on the PC board. The balanced sound could be due to the fuller BW but not that much after the second run of PM. At no time did it show problems with the upper mids. Not much to say about HF since the recording seems to not have any except for overtones I guess.
Antonio
PM
Before testing with the PH I heard several times the WP over the PM being the last time more critically and my general opinion was that it sounded nice and musical but lacking in the lower end (which was expected) even thou some mashing was heard at the end of the first movement and other portions of the WP and a shade of noise some places. Came to think that I liked the midrange and upper MR.
Second run.- found that I had neglected the Bass control that comes with the PM and started to play with it a bit, first full tilt and that gave and exaggerated feel of bass and was not pleasant (quite mushy too) so I backed a bit at a time until I got a more balanced overall sound, mo better, and came nearer to the PH, but sometimes (depending on frequencies of the music) the upper mid came to interfere with the musical event.
PH
A different animal, overall more balanced and deeper on the soundstage less grunge and almost not at all mashed over the heavier passages (not necesarly LF), also very few instances of perceived noise but who knows if it was on the recording or glitches on the DTA and amplification on the PC board. The balanced sound could be due to the fuller BW but not that much after the second run of PM. At no time did it show problems with the upper mids. Not much to say about HF since the recording seems to not have any except for overtones I guess.
Antonio
Frank, do you care about -
1) Flat and wide frequency response
2) Usable SPL
3) Low distortion at higher volume
In case you care about any of those 3 items, PC speakers are not for you. In case you do not care, please go ahead with PC speakers, but please do not convince the others who do care, that PC speakers are satisfactory for high quality sound reproduction.
Pavel, this is an exercise in learning, and I would suggest that Antonio is coming from this angle - correct me if it is otherwise, Antonio! With regard to your points, number 3) is the key one, and in fact it ties in with 2), very strongly. Point 1) comes in last, if the concern is for convincing sound; I have never worried about such, because it has never got in the way of me getting the sound I'm after.
Thanks very much for your feedback, Antonio, and thanks too to abraxalito for coming on board - you'll get plenty of good ideas from there, !
Okay, go straight to the heart of the matter, where you said for the PH, "less grunge and almost not at all mashed over the heavier passages" - this is where to put all your effort, you need to sort out where the PM is going wrong. For example, there may be an intrinsic problem with one of the drivers, a faulty unit, a problem buried so deep in the makeup of the beast that it won't be worth your while trying to get around it - I have a pair of pseudo-Altec PC speakers, and they're pretty terrible, raw, compared to the Harmans - it may be possible to sort them out but I haven't bothered trying.
So, concentrate on where you hear the grunge with the PM - is this a volume related issue, if you turn down the level is there a point where it largely clears up? And similarly with the heavier passage mashing, is this also volume related - can it be largely eliminated by running at a low enough volume?
!Okay, go straight to the heart of the matter, where you said for the PH, "less grunge and almost not at all mashed over the heavier passages" - this is where to put all your effort, you need to sort out where the PM is going wrong. For example, there may be an intrinsic problem with one of the drivers, a faulty unit, a problem buried so deep in the makeup of the beast that it won't be worth your while trying to get around it - I have a pair of pseudo-Altec PC speakers, and they're pretty terrible, raw, compared to the Harmans - it may be possible to sort them out but I haven't bothered trying.
So, concentrate on where you hear the grunge with the PM - is this a volume related issue, if you turn down the level is there a point where it largely clears up? And similarly with the heavier passage mashing, is this also volume related - can it be largely eliminated by running at a low enough volume?
I’ll give some background on my electronic knowledge just to let know. Not an EE but a Mechanical Eng. With 30 years of DIY audio electronics starting with SS kits from Dynaco and Borbely later went to tackle v. tubes pre and power did from scratch the Manly 150 W monoblocks (4 6550 each) with all transformers built by me (took 2 years to accomplish) built Zen amps and the Aleph 4 (100W class A). Also several speakers 3 ways and FR using raw speakers from Dynaudio, Fostex, Seas, Selenium, Peerless etc Plus fooling around with digital players. Have some test equipment but my Tektronix 7704 died last year so I’m crippled for the moment. - I can walk but a back injury and age keeps me lazy and don’t do much audio projects lately. But this PC audio seems easier for me and since I’m mostly at the computer is a logical little ‘project’.
In my experience, PC speakers need as good amplifier as standard hi-fi speakers, if you want to get their best.
I gave to a friend of mine JAMO E600
Jamo : Bookshelf Speakers : E600
to serve as PC speakers.
We found we can get very good sound when we use a good amplifier, not a chip toy. So I gave him one of my older projects
PM-AB1 error correction amplifier
and he has been very satisfied with the result, now for about 4 years.
I gave to a friend of mine JAMO E600
Jamo : Bookshelf Speakers : E600
to serve as PC speakers.
We found we can get very good sound when we use a good amplifier, not a chip toy. So I gave him one of my older projects
PM-AB1 error correction amplifier
and he has been very satisfied with the result, now for about 4 years.
We will appreciate positive contributions to the thread from anyone. We know the shortcomings from PC audio and we are trying to minimizing them so no need for you to call them. From your posts on the BT thread we know you are a perfectionist at audio so maybe this is not a thread for you dealing with underperforming chipamp audio which are not flat on frequency response.
Thanks for post 14 which is a positive input, I’ll look to your links, I don’t want to be rude to you, nothing personal.
Antonio
Thanks very much for your feedback, Antonio, and thanks too to abraxalito for coming on board - you'll get plenty of good ideas from there,
Okay, go straight to the heart of the matter, where you said for the PH, "less grunge and almost not at all mashed over the heavier passages" - this is where to put all your effort, you need to sort out where the PM is going wrong. For example, there may be an intrinsic problem with one of the drivers, a faulty unit, a problem buried so deep in the makeup of the beast that it won't be worth your while trying to get around it - I have a pair of pseudo-Altec PC speakers, and they're pretty terrible, raw, compared to the Harmans - it may be possible to sort them out but I haven't bothered trying.
So, concentrate on where you hear the grunge with the PM - is this a volume related issue, if you turn down the level is there a point where it largely clears up? And similarly with the heavier passage mashing, is this also volume related - can it be largely eliminated by running at a low enough volume?
I guess grunge is an incorrect word trying to explain what I hear, no problems from the speakers. I seldom hear at loud levels, mostly low to mid-levels over this close to ear speakers, about 3 feet.
First let me say that the system is quite musical but it does have a couple of offenders at some points during the performance, one is a peak at mids, to put a number say 800 to 1k Hz, evident in soprano voice. The other would be what I described as Mashy at some point of the WP somewhere at the end of the first movement (8 to 9 or so minutes) and not necessary happening with low frequencies. Seems more like an overload on sustain passages where various notes are played at the same time.
Hope this explanation helps.
Antonio
This is an open forum, as far as the forum rules are fulfilled, and I have replied on topic.
That's excellent, and your detailed experience means that you have a very strong feel for what's right and what's wrong.
That overload on sustain passages to me rings clearly that the power supplies are running out of energy reserves when a constant draw is called for, as a simple solution the smoothing caps need far more uF on board. My PC unit has the same problems still, if I feed it the wrong material, so I just back off sufficiently. My approach, in the past, was to over-engineer the chip amp supplies, 95% of the circuitry was PS: comprehensive regulation, then relatively huge local decoupling - zero overload problems.
It is possible that the mains power draw is exacerbating the situation - what I would do, as an experiment, is to feed the PC speakers the cleanest power possible: use a decent power conditioner if possible, and/otherwise devote a house circuit purely for the speakers, nothing else plugged in - so the source component is running off a completely different spur. Does doing this make any difference to the amount, and quality, of the overloading?
It's all about using simple techniques to isolate what is causing the issues - used carefully, it can tell one a great deal.
The soprano voice distortion may be due to the same issue, or it may be something else - I would try and resolve the overload first, and see.
In terms of loudness, it should be able to go substantially above what you listen at - my unit will happily fill the house, provided I don't go silly on the material: classical I can normally run at maximum, without audible problems.
Frank,
Since we can’t find a definite answer to the maladies I will do what I have done before on upgrading amps like changing caps at the active bypass positions and maybe others on the way while at it with better quality parts. Of course special attention will be given to the PS which is the most obvious as you also suggest. The transformer looks very small so I might also replace it. Wish I had a schematic. - Will see next week what I come with and report back.
Antonio
Since we can’t find a definite answer to the maladies I will do what I have done before on upgrading amps like changing caps at the active bypass positions and maybe others on the way while at it with better quality parts. Of course special attention will be given to the PS which is the most obvious as you also suggest. The transformer looks very small so I might also replace it. Wish I had a schematic. - Will see next week what I come with and report back.
Antonio
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