high bass speaker
- I am going to try to install my first high bass speaker. My question
is do I need to put in a tight enclosure or do I use the tender as the
enclosure. A friend of mine has installed 2 in tight enclosuers andhas
blowen both speakers. Jim
- G'Day Jim. You didn't state what loco tender you were installing the
High Bass speaker into? Doesn't really matter but I'm presuming you
have a 1.06" diameter speaker, the smallest.
Well, why don't you experiment with it & learn from the results as you
go. Firstly don't make an enclosure, just bench-test the installation
& have the speaker just sitting connected to the decoder on your work
bench. All you need to do is have "jumper" wires from the tracks of
your DCC to the bench. See how it sounds? Then make an enclosure for
it out of material at least 1mm or more thick - styrene or rubberised
cork or a plastic bottle cap - Still at the bench. If you experiment
with the THICKNESS of the enclosure & any materials you can think of
the more you will learn. Make the enclosure twice+ the size of speaker.
This is miniature stuff we are dealing with & presuming you are using
a Tsunami with a 1 watt amplifier we can't expect to get the same
sounds as from our expensive hi-fi systems - it just models we are
A friend here in Australia received High Bass speakers from Litchfield
Station with an imprint on the back of each HB speaker stating 1 watt -
not 2 watt as advertised. If your friend who blew up his speakers
received the 1 watt speakers then the sound will be terrible - you
MUST get genuine QSI High Bass 2 WATT speakers. Check the print on the
back of yours??? MUST BE 2 WATT.
You can use the tender body as the enclosure for the smaller HOn3
locos but personally I would not bother with a gasket seal between the
body & the floor, just get the speaker face to have a nice flat
seating onto the floor. I use medium density sponge placed on top of
the magnet so when the body is replaced the sponge acts as a spring to
gently force the speaker to sit with its face against the tender floor.
Again, try it without drilling any holes through the tender floor, it
can't hurt but you will experience what the sound is like. Then if you
feel it necessary, drill just a couple of holes & try this & each time
you will learn a little more. Hey, its fun doing this & YOU LEARN by
Once you have it right on the bench, then place it on the layout &
enjoy the better sounds from these great new speakers.
If I can be of further help please ask, I'm only too happy to try &
give my thoughts on things. Each loco is different so don't fall for
the trap of doing them all the same way!
Your friend down-under,
--- In HOn3@yahoogroups.com, "james hoffman" <james_hoffman@...> wrote:
> I am going to try to install my first high bass speaker. My question
> is do I need to put in a tight enclosure or do I use the tender as
> enclosure. A friend of mine has installed 2 in tight enclosuers
> blowen both speakers. Jim
- --- In HOn3@yahoogroups.com, "james hoffman" <james_hoffman@...> wrote:
>Why did he use 2 speakers? One of these new High Bass QSI
> I am going to try to install my first high bass speaker. My question
> is do I need to put in a tight enclosure or do I use the tender as the
> enclosure. A friend of mine has installed 2 in tight enclosuers andhas
> blowen both speakers. Jim
speakers will be much louder than you want or need.
Second... if he hooked it to a Tsunami, then he couldn't
blow the speakers unless he hooked it up wrong.
If he hooked the speakers in series, then he simply halved
the sound from each speaker. If he hooked them parallel, then
he loaded the Tsunami with only 4 ohms and could have blown
the Tsunami.... not the speakers.
Your not giving us enough info on your friends blown speakers.
If he put the speakers in an enclosure that restricted their
movement, then he TOTALLY defeated the speakers.
These speakers move in and out way more than regular speakers.
That's how they push more air and create more bass sound.
If you restrict that movement, then why bother with these
These are EXCELLENT speakers and a real improvement to
the sound volume and quality of DCC decoder sounds.
Your friend needs to figure out what he hooked up wrong.
And then take them out of confinement and let them do their
These speakers work just fine using the tender as the
baffle box. You don't need to build anything else.
Just be sure the speaker is facing down on the floor
of the tender....NOT up through the coal load.
Then make sure the speaker front and back are not restricted
by any foreign objects.
How could he possibly have blown these speakers?
They will take up to 2 watts and most decoders will
only put out 1 watt at best.
I suspect we aren't getting the whole story.
> --- In HOn3@yahoogroups.com, "james hoffman" <james_hoffman@> wrote:The best sound from any speaker, including the new High Bass,
> > I am going to try to install my first high bass speaker.
is to seal the front from the back.
This is best done by using the floor of the tender and then
the shell of the tender as an enclosure.
The speaker facing down through holes in the floor gives a
better/louder/basier sound by resonating off the roadbed/scenery.
The floor and tender shell, prevent the back side of the speaker
sounds from canceling out the front sounds.
So... ALWAYS mount the speaker this way if you can.
The only other improvement you can make is to dampen the vibrations
in the tender shell since it is thin metal.
As Laurie says, you can do this with several methods as he
has indicated. Sponge/cork/latex/etc. even electrical tape
layer on the inside will dampen the "tinnie" sounds.
But most of the time, the tender needs nothing more than to
be bolted back down to the floor. This effectively prevents
the reverse/canceling sounds off the back of the speaker from
reaching around and "killing" our front sounds.
Remember that every movement forward of the speaker cone,
is matched by an equal and opposite movement in the other direction.
That's why a speaker sitting alone on the bench will be VERY
soft sounding. If you sit it on the bench, then sit it on a
lumped up towel that surrounds the back and sides of the
speaker. You will hear more of what the speaker actually sounds
Also the towel will let the speaker cone move since it isn't
air tight. If the back of the speaker is air tight (bad) then
the cone is trying to move against air pressure and that will
cancel some of it's sound.
So we need the tender to be enclosed but not hermetically
sealed. In other words a couple small holes to let out the
air pressure is fine. Not too many.
Yet we want the hole that the speaker sits over to be as
big as the face of the cone if possible.
So ideally we would have a 1 inch diameter hole with the
speaker glued down over that hole covering it entirely.
Then we have a couple little holes with our wires coming
out to the loco to re-leave air pressure and the tender shell
fastened down firmly to the floor.
Optionally with a couple pieces of tape or cork on the inside
sides of the tender to dampen the shell vibrations. Laurie uses
a piece of foam in here which also works well.
Be sure you hook the purple wires to the speaker...no others
and make sure the speaker wires don't touch any grounded area
......that grounding could fry the speaker or decoder or both.
I prefer to use a couple little dabs of rubber cement on the
edge of the speaker to hold it firmly to the floor.
Don't get any on the cone.
I find there is less rattling of the tender from the speaker
and thus better quality sound with the rubber cement.
-Have fun.... hope this helps. I love the new sounds on my RR.
- Heat is another matter I try & deal with - the heat given off by the
Tsunami. The tiny transistors are working hard & generate heat so to
get an area in a tender that allows holes to relieve this heat is
something I try & do. (Drill holes for decoder)
Space is the trick to manage here as the speaker needs to have an
enclosure to cancel out the air movement at the back of the speaker
yet a couple of holes to help air get to & from the decoder which
gets hotter the longer we run the loco is a factor I try & deal
with. On the Tsunami there is a big flat area which is where the
transistors are & the heat generated, so try & have this against the
brass tender wall or floor so the brass acts as a heat sink to help
a little. (absorb some of the heat)
I use rubberised cork to make a wall between the speaker & the
decoder & I also use it as a sound absorber / anti harmonic
vibrations material too.
The new Micro Tsunami has allowed the smaller HOn3 locos to be able
to have sound (decoder & speaker fit in tiny tenders) & these are
terrific. Steve Hatch put me onto the QSI High Bass speakers which
are 2 watt & these are just the best deep sounds that are soooo good
to listen to. You must be very careful grinding the sides of these
speakers so that the metal & plastic frame holding the speaker
proper don't let it colapse. I grind a tiny bit of the brass tender
shell walls so that a very thin piece of insulation tape can be
placed on the sides to prevent the resonating vibrations of the
speaker touching the brass tender - tricky work but very do-able.
Now, separating the speaker & enclosure from the Tsunami all inside
the tender - well this is a case-by-case thing. I usually fit the
speaker under the coal load so I can get the height of the speaker
inside the tender - the coal load can be raised. This then leaves
the rear section water tank area for the decoder. On C-Class & using
the M/Tsu's the wires lengths are just a bit short sometimes running
to the loco (motor & lights wires) so you need to make a terminal &
run extra wires as needed. I have found a little strip of PCB works
& it makes it easy for maintenance - just unsolder the wires if
Steve has his HB speaker photos previously placed here & I have a
couple of articles with photos & how the r/cork is used as a wall
(see Laurie's University in Files)
Steves info is spot-on, go with it.
Your friend down-under,
- Laurie and Steve thanks for help with high bass speaker. the blowen
speakers were two seperate installs in the same engine. they were
installed with the side and back enclosed . I plan to replace a
speaker in a K37 with the 1.03 speaker. since the tender is larger than
a c16 should i put enclosure around speaker leaving front and back
- Hi Jim, you must enclose the air behind any speaker. For the K37,
which has a large area inside the tender you will need to use half
of it for the speaker sealing off the area behind the speaker. The
other half will have the decoder (Tsunami 750 I suggest). You stated
1.03" the QSI are exactly 1.06" dia - 30 thow difference is a lot -
You could get an enclosure to suit the QSI HB speaker from TTX.
Read the information on TTX site as it explains things about the
enclosures & suggested area sizes, too much to discuss here.
I do suggest you experiment on the workbench & before drilling too
many holes test each step that you do - you will learn so much about
sound & what is good & bad, do please try experimenting.
If you get to a stage where you are worried about a particular thing
then post here & we'll try & walk you through it.
On the HOn3 chat site I did a series of articles for a friend in a
step-by-step to install a tsunami into a MMI k-27 with a HB speaker,
this may help you also its put in a way for beginners - check the
Good luck & good on you for giving it a go!
"james hoffman" <james_hoffman@...> wrote:
> Laurie and Steve thanks for help with high bass speaker. the
> speakers were two seperate installs in the same engine. they werethan
> installed with the side and back enclosed . I plan to replace a
> speaker in a K37 with the 1.03 speaker. since the tender is larger
> a c16 should i put enclosure around speaker leaving front and back
> open. Jim
- Jim, I just added 2 photos showing the rubberised cork I use to make
the enclosure & separate the decoder area. See photos - Laurie's DCC.
The reason for separating the front of the speaker from the back is to prevent out-of-
phase sounds from the back of the cone, canceling out the in-phase ones at the front.
This is known as comb filter cancellation, it affect mainly the lower notes, the very ones
we are trying to propagate and you can demonstrate it yourself as Steve Hatch suggested
by lying the speaker on a towel or more simply wrapping your fist round the edge of the
speaker. So to separate the two sides the idea is to use an infinitely large baffle or piece of
wood so that the front and back waves never meet. Of course, that is impossible to
achieve so the next best thing is to seal the front from the back using a box. But how big?
A speaker has what is known as a resonant frequency below which the bass response will
reduce or roll off. A sealed box will trap the air inside and create an air spring which the
cone will have to work against. If the box is big then this won't have any real effect on the
frequency but if the box is small it will raise the resonant frequency and therefore
diminish the bass response. So it follows that the bigger the box, the better the bass.
That's something we all know anyway through HiFi speakers. So nothing new there. But
one way of making a small box sound bigger is to fill the box with a dampening material
such as foam or pillow filler - I use cotton wool. What this does is to relax the air spring
effect and lower the box resonant frequency. Note that I do not mention any form of tape
because this is merely another reflective surface - it has to absorb accoustic
energy for the effect to work.
OK so know we have the biggest box we can manage, filled with cotton wool. What else?
The seal of the speaker to the baffle is really important. I glue mine down and then seal the
edges for luck (probably overkill). But what about that cone moment. These super bass
units have an accoustic suspension and the cone travel is much bigger than on Kobitones
or anything else for that matter so you need to make a baffle out of styrene. Pointing up
or down? I know Steve is adamant on this and I agree but perhaps for different reason. The
floor is the stiffest part of the tender and I think that makes a real difference.
How good a seal? The best you can manage. On a real sealed box, you have to drill A tiny
hole to equalise the inside with atmospheric pressure - I don't thing we'll achieve that
kind of seal here.
Finally Heat. I think the MMI K-27 has it right when it allowed the decoder to be fitted in
the boiler. The big disadvantage of filling the tender with pillow filler is getting air
circulation for the decoder to keep cool. but on balance it sounds heaps better.
This whole thing is a voyage of discovery and a great deal has to be found ut yet dealing
with these miniature sizes. We're just starting off on the trip.