I have been exploring speaker mount options for my P2K GP30 locomotives. I have come up the following potential solutions. I would like to hear what experienced installers say about my proposed alternatives and which they would recommend.
Rear location under fans
Option A ESU 50321 11x15 by 3.5 mm deep speaker mounted over rear light
Option B ESU 50321 11x15 by 5mm deep speaker mounted under larger rear fan
Comments: Option A wins on ease of installation with no milling required. Option B puts the speaker under a larger fan vent (14mm vs 9mm) but requires some milling and removal of the weight from chassis during milling.
Questions
1) will sound be better through the larger vented fan?
2) The speaker will be a few mm's below the vent, okay or a problem?
Cab mounting
Option C Mount ESU 11x15 by 9mm deep to rear of cab (mounted vertically)
Option D Mount ESU 11x15 by 9mm deep to top of cab (mounted horizontally)
Option E Mount a shortened iphone 4 speaker to bottom of cab
Comments: Option C is the simplest option (assuming double sided tape will hold) and no milling is required. Option D involves removing the light cone adding more wires to light 2 headlights and number boards + add resistors. Pretty crowded inside on the roof. To my ears, there is little difference in sound quality between 9mm thick vs 3.5 mm thick ESU speaker based on youtube video. Maybe different in my install. Option E is pretty straight forward with cutting down the Iphone speaker and attaching with double sided tape. Option E has advantage where sound is closest to front truck and directed down.
Questions:
1) Sound exits through the front truck. Will sound quality be poorer with a vertical speaker mount vs a horizontal mount?
2) Sound quality of Iphone speaker versus ESU sugar cube?
Given the above, which option would you choose or recommend?
Is there a way to test speaker combinations without having to solder and remove between speakers?
Hi,
I used to concern myself about "where the sound is going to come out". After about thirty installs on several styles of HO steam and diesel engines I don't much concern myself over it anymore. Of course, with steam I don't want a totally enclosed tender, even some vintage brass has speaker holes in the floor and on some I have drilled tiny holes into the coal load.
I haven't tackled a L-L GP30 yet but I have a few ladies-in-waiting.
I recently did an SD9 and found space for two ESU 50321 speakers where you can stack up the pieces to make different configurations, one of my favorite speakers.
SD_9-decoder-7 by Edmund, on Flickr
Likewise I fit two cube speakers into a Genesis GP9:
GP9b_PRR_Tsunami2b by Edmund, on Flickr
I don't find any problem with the sound coming out through the truck pivot openings.
I always test the speakers I plan to use with an MP3 player and a low-watt amp.
SPKR_test by Edmund, on Flickr
I can play with series/parallel arrangements and also make sure the speakers I'm using are not defective in some way.
SPKR_test2 by Edmund, on Flickr
I recently installed my first I-phone speaker in the long, skinny shell of a Bowser Alco C-630. To my ears they sound OK but not that much better than the smaller-sized cube speaker. I had the space so I thought I'd try it.
Bowser_Century_DCC by Edmund, on Flickr
Iphone_speaker by Edmund, on Flickr
Good Luck, Ed
Ed, thank you for your very helpful description of your installs and pictures! I was pleased to read that you consider the ESU 50321 one of your favorite speakers, a positive recommendation for me to use it! To my untrained ear, it sounds decent and good choice. Your comment seals the deal! I should be able to install a speaker in the cab and one below the fans. A couple questions:
1) Does it matter, sound quality wise, if one speaker has a shallow baffle (4 mm) and the other has a deep baffle (9 mm)?
2) I have found conflicting maximum wattage numbers for the 50321, some say 0.5 W and others say 1-2 W. Given that the Loksound decoder has max 3 W output, it seems that speakers should always be wired in series to avoid overdriving the speakers and allowing the amp to run cooler and more efficiently. Do you agree? I'm a newbie at this so could be not fully comprehending correctly...
Here is an idea but does requiore some frame milling. I think this is your loco model.
http://tcsdcc.com/installation/ho-scale/1403
Rich
If you ever fall over in public, pick yourself up and say “sorry it’s been a while since I inhabited a body.” And just walk away.
Thanks Rich, I have seen the TCS installation example for a LL P2K GP30. I have come up with two speaker locations that do not require milling and should work as well. IMO. We'll see. Can always do the milling later if this first approach does not work. Thanks for looking!
I find the difference in the baffle or enclosure size to make only a negligible difference in the sound output. Sure, the larger enclosure, using all the components of the kit, probably has the best "low-end" response but, of course, so many things we do in the model world requires compromise.
Two speakers, to my ear, give much better sound output than one, even if the second speaker is in a smaller enclosure. I generally wire in series but there are times when parallel works better, especially with mis-matched speakers, where one might be less efficient and if wired in series, has little output.
In those cases parallel might work better, within the constraints of audio wattage on the decoder. Using that little amp shown above I've been able to drive those little cube speakers pretty loud without clipping. Much louder than anything I would want on the layout. I keep sound levels toward the lower volume.
You can easily adjust the levels on the programming track, of course.
When soldering to those cube speakers be sure to have the speaker secured in such a way that they don't jump up to the soldering iron! I use a small piece of double-stick tape to hold them in place while soldering.
SD_9-decoder-sp1 by Edmund, on Flickr
Place a tiny dab of solder on the contact, tin the wire you are attaching (flexible 30 ga.) and carefully touch a little heat to make the bond. I also slip a tiny length of heat shrink on to the joint.
Iphone_zoom by Edmund, on Flickr
I found another handy product for sound installs and that is 3D fabric paint. You can see it at the wire connection on the I-phone speaker. This stuff acts like caulk. It dries fairly fast and is ideal as a stress-relief, sealant.
When I make those ESU speakers there is a fairly wide gap where the speaker itself meets the enclosure. This stuff seals that gap up perfectly BUT it is not so tenacious that it can't be removed if needed.
I don't really know if it helps that much or not but I also like to place a few strips of "fuzzy" tape to the inside of the shell. I believe this helps aleviate rattles and helps reduce some of the extreme high end of the speaker.
Works for me
Cheers, Ed
I did convert a LL GP30 awhile ago. I installed a LokSound Select 6Aux, which is the 1A motor capable, in shrink wrap form.
The decoder sits above the motor. I like to build my own 0.040" styrene speaker enclosures and maximize the size to help the low end. Having done several locos with 2 or 4 speakers, I found this loco seemed right to try 3, but that required milling the frame.
The three 8-ohm speakers were wired to make a 5.3 ohm setup, fine for the Select, which likes 4 ohms but is dandy with 8 or even 16 ohms. Fortunately, I have a friend with a CNC milling setup so I can ask to get the weight modifications I prefer.
I originally was using Knowles Grand 13 x 18 mm 8 ohm speakers, but those became unavailable. I switched to CUI CDS-18138A 13 x 18mm at that point, leaning on some speaker test comparisons by a Larry Hanlon, on a LokSound user group. I think the GP30 got the CUI's, but my notes are not specific, and I would have to check inside the shell. Both those speaker types came from DigiKey, and both are now discontinued. I have a supply and have significantly slowed my loco conversion needs. The DigiKey inventory is so large that novice me can not realistically pick anything there without a recommendation.
in any event, it was a neat project, that performs well. I will admit that I do not focus much on where the sound comes out in a diesel, as there is lots of space around the trucks for sound to find its way out the bottom, if needed.
IMG_6155 by Paul Ahrens, on Flickr
IMG_6216 (2) by Paul Ahrens, on Flickr
Paul
Modeling HO with a transition era UP bent