Can someone comment on my hornresp simulations on the MCM8?

[Thawach]

i'll try FLH if the 8:1 ratio is good, i'll try to do many thanks friend

[blamus]

btw, i have to ask a noob question.

Does it matter which orientation I test the woofers at? facing up? on its side? I ask because when I put the play dough on, I was thinking, surely when facing up gravity comes into play?

[Thawach]

blamus this's good if i read and know that many freinds who have experience to share. and if i simulate i'll consider again.

[mwmkravchenko]

Gravity will mess with a true center position measurement of the voice coil. But for what you are doing is trying to find moving mass due to changes in impedance. So it really does not matter to much.

Mark

[blamus]

Originally Posted by JLH

You can't easily use a passive crossover with a tapped horn. I've gone around and around with this using Akabak software. Unlike Hornresponse, Akabak has a means to simulate passive crossover components. The passive components mess up the electro-mechanical tuning of the tapped horn. The best route is to use an active crossover in front of the amplifier.

Thats what I thought. now I know!

In addition, the T/S parameters for the MCM 8" are all over the place. They also change quite a bit after break-in. The suspension gets sloppy on these, so Cms changes a lot. To save you some trouble, give those MCM 8's a good break-in period and then measure the T/S parameters yourself. This will give your project the best chance for success.

I will post the break in measurements next week. Can i break them in by playing them on the floor in free air? Does it matter if the vent at the back is covered this way?


Jbell
thx for the sim, I've added that to my hornresp collection to fiddle with I have a few I made that has the same slope, but yours has much higher SPL. But my "bass corner" is at 30Hz instead.

And THANK YOU for your encouragement on not giving up on eliminating the noise problem on the headunit (if you remember our discussion on the other thread) I finally opened the HU up, gone down to the PCB and bypassed a blown pico fuse. Not easy, but done. Now I can use my amps again, and have bass while I play with all these horn thingys

Because I now have power (RRRAAAAHHH!) and understand alot more what I should be looking for - I would like to start with a FLH with the w6-1139SI. Many TH has been done with this thing, I can only find 1 FLH - the insubnia FLH version by maxmercy. (later it turned into the arnachy TH). But at the minimum I'd need to refold it (to 7inches tall to make it as flat as possible)

Here is my try: (see attached) 2.83V, single w6-1139si, 45L, 30Hz.

The problem is that I don't know how to design the compression chamber. Any fast rules to help? Any existing designs that I missed?

[jbell]

Originally Posted by blamus

And THANK YOU for your encouragement on not giving up on eliminating the noise problem on the headunit (if you remember our discussion on the other thread) I finally opened the HU up, gone down to the PCB and bypassed a blown pico fuse. Not easy, but done. Now I can use my amps again, and have bass while I play with all these horn thingys

YEA -- good for you.... finding the 'right' answer... is always the right answer.

[JLH]

When breaking in new woofers I try not to block off the magnet vent. Whatever heat is generated, I want it to be able to get out. Thus far I've just propped them on edge and played the radio through them while I'm gone at work. After about 3 days of this the T/S parameters seem to settle for good. I give them enough power to get visable cone travel, but not enough to bottom out the voice coil.