QUOTE (Piemanlarger @ 23 Jan 2008, 20:07)
<{POST_SNAPBACK}>So something better than the base relex must be in development
***New speakers - you are an optimist
It'll be interesting. don't hold your breath...... I'd just be happy its been made and live with the way it'll be delivered....
It looks to be really nicely done, and I will make a rare exception to my generally diseasel free layout and buy one as it had some early test runs on the Settle and Carlisle.... (I'll have to do a back to the future though - my layouts set in the '30's... but then it still hasn't changed up there, has it!!!)
BUT - Don't look for anything other than the character of the sound - the energy won't be there - ever!
Big Bass isn't at all easy - I have a history in full size audio design / development, do hundreds of sound installs a year and I'd say its 100% physically impossible to get "real diesel bass energy" inside a 4mm scale powered loco.
Not easy in bigger ones either - I just did a large scale Aristocraft SD45 and Dash 9 loco - they sound truly great and are identifyable sound wise as what they are - but big loco sound is FELT more than its heard - and thats still not there!
It can sound GOOD, very good sometimes, but it will never have the high energy you are talking about...
Why?
If U build a 100 watt hi-fi speaker it'll have a 100 watt woofer, a 10~15 watt midrange and a 1~3 watt tweeter (appx). This is because the energy to reproduce bass sound is way, way more than to reproduce mid and high sounds. (The crossover takes care of splitting up the sound so bass notes don't fry tweeters etc...)
No matter how good the speakers will be, a cone of such small surface area will NEVER reproduce bass frequencies in any form of balance with the higher frequencies - the efficiencies are just too different.
eg to stay in balance and deliver real bass.... the total output power of a loksopund 3.5 is appx 1 watt
... to get the other frequencies loud enough to do what U say and keep bass in balance will need both higher power (5 would be nice, but OK at about 3 or more possibly) for the bass frequencies and say 1/2 watt for the lower mid to mid and 1/5 watt for upper mid and highs.
this will also need a slow roll off or the low end of the speaker - which means a perfectly sealed enclosure not a bass reflex, which rolls off very sharply. Little speakers do well to even start to reproduce 300hz which is really only low midrange - real bass starts for me at 150 and goes down from there!!
AND - the existing 8 bit sound cannot cover the bass extension either..... its bandwidth is actually quite narrow.
So..... as I said, with sound decoders in their current form, don't hold your breath. Especially if B do their usual and fill the body with metal so it'll pull well. A milling machine is needed if thats the case....
We have to fool the ear by gaining everything we can....
The practical solution is still not a walk in the park:
Use more than one speaker with them configured in phase - and in parralel.
Use identical speakers in a series/parrralel array with an imedance of not less than 50 ohms rather than one small, one big. More cone area = important!
BOTH the original Loksound (if placed in its enclosure and perfectly sealed - including the wire slots) and the DCCsupplies bass reflex speakers are both very good but speakers are only part of the equation.
It will need a sound file recorded at a good energy level and kept as close to clipping as possible which is then severely equalised and it may also need to be slightly phase shifted to preserve the lower end of the audio when its taken from whatever to 8 bit audio....
It will need several speakers and the loksound run at 50 ohms, not 100. Personally I always use a sealed box as its bass extension is better IF you can effectively couple the speakers to the body and create a true sealed enclosure... but the DCC supplies will be better if precision isn't possible.
It will need the volume set to about 90% not 100% (it'll sound cleaner - the top ten percent is mainly distrotion, heat and wasted energy anyway.
and a lot of good luck - technique and skill are a big bit of it, but luck happens too - some installs just work really well!!
sometimes simple things help too - if the top end is limited on purpose by masking it, the bass sounds louder - relatively speaking!
Richard
PS: don't let the above stop U trying - as my second-to-last line said - good sound is part science, part magic and part luck
