Hi, all. I made some more progress on the learning curve yesterday and would enjoy posting some info. Any comments are most welcome.
I didn’t like the 2012 GP-9 factory sound and really liked the LokSound (with 2 1.1" HiBass speakers and 12 cyl EMD 567) I recently put in a Lifelike P2K E6. I ordered the LokSound Direct board for the GP-9 loaded with the EMD 16 cyl sound file. The board replacement was pretty straightforward but the speaker room of course would not accommodate a 1.1" HiBass pair (parallel gives 4 ohms). The following shot shows the Tsunami board and factory oval speaker enclosure atop the truck.
Of course the direct board is easy to deal with as it fits atop the holder prongs. I haven’t addressed adding LED lights yet (which will be tight at the long hood end). I concluded I could fit an enclosure with dual sugar-cube speakers (iPhone5 type) that arrived from Digikey. I bought some 11x15 and 13x18mm size. I could not fit two 13x18 unless building the enclosure in place between the hood walls, wanting an independent enclosure for this first shot. So I put one of each size in a styrene box, wiring them in parallel (since different I had to interpret the data sheets), and making the enclosure 12mm deep. Some shots follow:
I agree that the E6 with dual speakers sounds a little more robust. It would be nice if we had that sort of space available in all our engines, but alas…
One thing I noticed with your sugar cube enclosure is that you have the diaphrams (the moving parts) pointed to the outside of the enclosure. The examples shown on the Streamlined Backshop website have the baffles over the moving parts, which is how I have done mine. http://sbs4dcc.com/tutorialstipstricks/sugarcubespeakernotes.html
Both seem to work so I’m not sure what the logic is with having the diaphrams enclosed, other than for protection maybe.
I’ll send Bryan at Streamlined Backshop a note and let you know what his response is.
When using speakers inparallel, their total wattage handling is the sum of the total wattages. In your case, the two 0.6 watt speakers could handle a total of 1.2 watts or 2 watts total peak. If I recall correctly, the Loksound decoders are capable of a full 2 watts of power.
My concern, more than anything, would be the use of two dissimilar speakers in the same enclosure. With two different waves frequencies coming off the front and back of the speaker, it may create some rather odd harmonics. You could minimize this by placing a wall inside the enclosure to separate the backs from each other, but there will still be a variation from the front.
Common speaker cabinet design always stresses to never use two dissimilar drivers in the same cabinet. You would probably have netted even better results using two of the 11mm X 15mm together if space was a concern.
Thanks for the info on the parallel wattage capability. Also interesting regarding the two different sizes combined. Of course stereo 2-way and 3-way speakers have several sized in one box, but they have crossovers that send most of a frequency range to the right one, and may use dampening material for a reason I forget. I could have used an internal thin separator piece.
On the importance of which way the speakers face (in or out) I think the following may be helpful. Here is the general page but also see the part (there’s another page) on “inverted” cone sealed boxes. It seems to suggest no sonic difference. That may be hypothetical, as there may be minor effects. But it may not be as critical as getting the system pieces (speaker, any gaskets, box pieces) properly fitted and glued / sealed together.
It really helps to have the speakers in hand. I can readily see that two of the larger ones will fit side by side crossways in my RS-2s, if I mount them near the top of the walls in the long hood and just put baffle pieces on each end, using the solid hood top and side walls to complete the box. The box would not be as deep as the GP-9s, however. And everything would be glued in fairly permanently.
I’m a little over my head here (hear) so hope I don’t make any fatal errors that can’t be corrected without a new loco. Fortunately the speaker parts are inexpensive.
It’s fun experimenting with these to see what works better / best.
As for multiple speakers in the same cabinet, as you mentioned - the important aspect in home stereo speakers with different sizes is that a cross-over network send different frequency ranges to each of the speakers, so there is no conflict.
When using full range speakers (right down to these little guys), they should be of identical specs.
Another electronics detail crosses my mind. When two of the sugar cubes are put next to each other the magnets in this case repulse each other a bit (push each other away about 1/4"). Superglue overcomes that, but I wonder if the magnetic fields when forced together are bothered enough to affect the speakers’ performance in a significant way? I’d guess not enough to matter??
I think over time you could have loss of efficiency from the interacting magnetic fields. Magnets DO lose power over ime, some compositions more than others.
Great thread and great job by the OP. I am a retired audio engineer. There are some interesting points here.Perhaps conflicting harmonics might not be a bad thing when reproducing large diesel engine sounds?
I’m kinda guessing at this but don’t diesel locos produce all sorts of low frequency harmonics prototypically?
For music and quality theater sound reproduction harmonics (unwanted that is) and distortion are not a good thing. Different sized speakers in the same cabinet are not uncommon in high level ($$$$) audio enclosures. Although pro cabinets will frequently use active crossovers (freq division before amplification)the cabinets will have separate enclosures inside them for different frequencies. High-mid-low, etc.
Lastly, having 2 speakers in close proximity can have a coupling effect.That is the sum of the 2 speakers is greater than 2 speakers of the same specks being further apart. In this case I would think having identical speakers close coupled in the same enclosure with the same input would be a good thing. IMHO $.02
Great job guys.
PS do the Proto 2000 E 7, 8, 9, , etc have 8 or 9 pin DCC plugs? Speaker mounting positions? Thanks again
First, about the 1.1" HiBass speakers with enclosure. I went with these, from TonysTrains in two Bachmann 2-8-0 conversions to sound basis their recommendation for speakers of that size and liked the idea of the provided enclosure. Since two of them would fit the LifeLike P2K E-6 atop the weight (if removing the factory board), I figured that was the best bang for the space available (I had to grind the weight slightly). They are $12 each. I don’t know if you can buy the raw speaker there or elsewhere to build your own enclosure if so inclined:
On the E-series P2Ks, all I know is the two E-6 Lifelike P2Ks I acquired. I can’t comment on other E locos. My E-6 QSI Quantum roughly 2004 (blue box) is sound equipped (not in these videos), and the speaker recesses for two 1"+ speakers are in the frame. But I’m not enamored of the Quantum motor control quirks (or I don’t understand how to adjust it). The E-6 LifeLike P2K you see here (gray box) came with 8-pin plug. I don’t know when built but it has a lower model number than the other, so maybe earlier. While there was an 8-pin plug, it lacked the speaker recesses in the frame for two large round speakers, so I removed the lightboard over the rear of the frame and ground off the screw protrusions which made a nice space for the two 1.1" HiBass (but covering the two rear frame screws). And I changed the front bulbs to LEDs.
On the subject of different speakers combined. First, I know little. On harmonics inter
I got an e-mail from Bryan at Streamlined Backshop. He said that he has always oriented the diaphragm to the inside of the enclosure because the sound in the sugar cube speakers comes from the magnet side of the speaker, not the diaphragm. He admitted that he has never mounted them with the diaphragms pointing out, but he said he would give it a try.
He admitted that he is still experimenting with sugar cube speakers, but he has done more than 100 installations with only three situations having problems. Those problems all occurred with the exact same combination of decoder, program cab and operating cab, and they turned out to be related to the decoder programming and not the speakers themselves. You can read more about that on his website:
So, the official jury is still out on whether or not the diaphragms should point in or out, but I’m inclined to say that Paul’s installation shows that it might not make too much difference since his seems to work quite well.
His problem and suggested fix is actually in the Loksound manual - it recommends disabling all protocols not being used (for Loksound V4 - which handles pretty much all digital protocols ever used. Digitrax, unlike his MRC Prodigy system, supports the Marklin/Motorola Trinary protocol as well as NMRA DCC, so this is probably why there are some wierd things happening with customers that have Digitrax. I didn;t compare an older version of the Loksound manual, but the version I looked at yesterday does have a paragrpah under the section for the various protocols where it mentions disabling everythign except the one you plan to use. And they put a good bit of safety check in there - it says it will not disable the protocol used to change the CV, so if you try to turn of NMRA DCC using an NMRA DCC program track, it will ignore it. And you can never disable Lokprogrammer protocol, so even if somehow you manage to lock out everything, you cna still access the decoder using a Lokprogrammer.
Further on the issue of which way the sugarcube speakers face, they are now shown at Tonys Trains and they say the “cone” / membrane / speaker should face into the enclosure as noted before basis SBS experience. Tony’s quotes a fraction of the distortion attained with the membrane facing out:
I don’t understand this but will accept it. Nothing like data, for an engineer. I would think either it would not matter, or the casing on the magnet would act as a semi-enclosure and reduce or affect the sound out the “back” (magnet side). But it may have to do with design. Maybe they are intended to be installed in phones that way and have features about the casing that optimize the sound coming out the “back”.
Not being a “denier” (on this subject), I finished my first (skinny) Kato RS-2 yesterday and installed two 13x18mm speakers (with LokSound) in the upper roof. I faced the membranes up to the solid roof, where the sides mated with the roof curves. I added styrene enclosure ends on each end and sealed the rather small enclosure space with silicone. It works, but I’ll report on that in another thread after I do the 2nd RS-2. The question there is whether to do the 2nd one with the smaller 11x15 speaker pair, just for comparison. The 13x18s fit the width very nicely, so I’ll likely repeat that. And BTW, they should sell DCC shoehorns for stuffing the wires in an RS-2 with decoder, LEDs and speakers. I think I’ll defer to others the sound conversions of the small GE 44/45-tonners. And then there’s N scale!
