My 103E Rear loaded horns

[shporsche]

Hey I'm new to this forum and new to the speaker building scene.
I've really only designed 2 pairs of speakers, a open baffle mid speaker and standard 2 way main speakers, so really not that much experience in building. I have however modify alot of speakers, not that they sounded that good.
I have a bit of knowledge as I work for a electronic company and have worked in various hifi stores here in Aus.

I built a Pro series 3 poweramp from Jaycar a few years ago and wanted a decent pair of speakers to suit.
So I went looking on the net and found Fostex full range drivers.
Going on price I really didnt want to spend anymore than Aus$300.

So I ended up with the 4"103E.
I didnt know what I was going to do for a box until the speakers turned up, they had a slip included in the box with a loaded horn design. It looked like a challenge, so I started it.

Aus$90 for the cuts and 16mm MDF and $120 for the speakers.

Here is the pics of my build process.
I dont have a finish on the box yet, it will be vaneered with redgum.

Please tell me what you think.

[loninappleton]

These should be very enjoyable.

In case no one else says this, go easy on the stuffing or begin with a minimal amount.

Your basket treatment is interesting. It looks less messy than using
putty on the legs. However I can't see the seam. How was the foam cut and held in place.?

[Bob Brines]

Putty on the basket legs and foam padding serve two very different purposes. The putty mass loads the legs thereby damping internal resonances. The foam blanket absorbs reflections bouncing around in the cabinet. My personal opinion is that 1/4-1/2" of putty is not going to do much, if indeed resonances in the legs is a problem to begin with. Also, if you put a reasonable amount of stuffing behind the driver, there is little in the way of reflections left to absorb at the driver.

Your treatment looks nice and I'm sure it does no harm, but it appears to be a solution in search of a problem.

YMMV
Bob

[shporsche]

Thanks for your comments.
The Putty I'm using is a speaker sealant from Jaycar, Ive used that in between the magnet and case. The foam I'm using is a honeycomb material sound absorbent mat, it has self adhesive backing.
I used as its easy to work with.

[rjbond3rd]

shporsche, nice work -- how do they sound? How long did the assembly take?

[shporsche]

Hey Bob you make a good point about the reflection and dampening on the speaker material I have used.
I was going of what I have seen and studied from the Net. Never thought about the property's of what there doing.
I wouldn't have thought the putty would make a difference being on a 4" driver, as there is not much going on compared to a 10" or 12".

This is all new to me, so your opinions are very welcome.

The speakers sound great to me, however when there is a person with a large voice comes on it becomes very ear piercing, almost to much top end or it cant handle the top end, I really dont know.

I mentioned this to an acquaintance who know's abit about speakers and suggested I do some testing with a parametric equalizer. Once i have the correct value use a notch filter to set in stone.

[Bob Brines]

Originally posted by shporsche
....however when there is a person with a large voice comes on it becomes very ear piercing, almost to much top end or it cant handle the top end, I really dont know.

I'm not sure what you mean by a person with a large voice, but I do know that this driver has a strong peak at 7kHz. This is right where the sibilance is with spitty singers. Put a 6dB cut at 7kHz and see how that sounds.

Bob

[shporsche]

[QUOTE]Originally posted by rjbond3rd
shporsche, nice work -- how do they sound? How long did the assembly take? [/QUOTE

Assembly took 2 days, liquid nails certainly works a treat.

[shporsche]

Originally posted by Bob Brines


I'm not sure what you mean by a person with a large voice, but I do know that this driver has a strong peak at 7kHz. This is right where the sibilance is with spitty singers. Put a 6dB cut at 7kHz and see how that sounds.

Bob

Thanks Bob, I will try that now.
In regards to the large voice, I mean a powerful singer.
i.e Radney Foster, Elton John, Christina Aguilera all have powerful voices.
When they are really singing, right on there vocal limit it can sound piercing.

[shporsche]

Originally posted by Bob Brines


I'm not sure what you mean by a person with a large voice, but I do know that this driver has a strong peak at 7kHz. This is right where the sibilance is with spitty singers. Put a 6dB cut at 7kHz and see how that sounds.

Bob

Please ignore my ignorance, how do I achieve a 6db cut at 7kHz?
With a choke, notch filter?

If Notch what do I require? caps, coils, resistors.
What values do they need to be?

Thanks guys for your help.