MY BAD THOUGHTS - Noidster's Fault *PIC*

[hongrn]

Alright. This is what I'm plotting next. All Noidster's fault for selling me 2 RS180s in the first place. Then PE had the RS180s on sale last week (DOTW). So I got 4 more. Then I went nuts and got 2 10" RS subs, the HF variety. Then 3 Seas H1212 tweeters from Madisound. Wholly cow, if my wife saw the MC statement, I'll be as single as Shawn.

I'm going to build 2 MTM vented towers with these babies. The RS subs will be incorporated in the towers, in their own enclosures, turned sideways to keep the cabinets narrow. The MTM box will be around 1.1 cu ft, 1.6 for the subs. Total internal dimensions are approximately 55H x 7.5W x 12.5D. Weight? Probably 1.5 tons :-). MTMs probably crossed at 2KHz, LR4, impedance compensation and 4dB BSC. To keep the weight down, I'm thinking about building a box to house the 2 sub amps, and then run heavy duty speaker wires to the towers. Wish me luck. I need to finish these before my wife finds out how long I've been AWOL. And Noid started all this... Ain't my fault.

[dancarroll]

If he did, those cones would be inverted and encased in something skimpy and likely red in color.

[shawn_a]

Single as me?!?! You don't even want to go there. You will have so many drivers hanging around the house you won't know what to do next. You'll be wearing large purple sombreros before ya know it.

What you have laid out there looks pretty nice. Hmmm. Very nice indeed. Me need to not look at Hong's picture too much. I have bad thoughts now.

And yes, blame it on Noid. It works well.

shawn

[hongrn]

> If he did, those cones would be inverted and
> encased in something skimpy and likely red
> in color.

Ahhh... The floatation devices...

[cjd]

> MTMs
> probably crossed at 2KHz, LR4, impedance
> compensation and 4dB BSC.

Reconsider. I would cross no higher than 1800, with 1600 being a very good spot in my experience (that's where my big 3-ways are crossed now).

The Seas tweeter is up to the task.



Check out Jon Marsh's Modula design as well - initially built with the 27TDFC (silk dome version of this tweeter) and crossing around 1400Hz, it's pretty darned maxed as far as design. Will make the speaker deal REALLY seem like a deal. But the sound IS worth it. HTGuide.com for that. If nothing else, you may pick up some design and topology ideas.

[hongrn]

> Reconsider. I would cross no higher than
> 1800, with 1600 being a very good spot in my
> experience (that's where my big 3-ways are
> crossed now).

> The Seas tweeter is up to the task.

Hey, you're right! I forgot to check the Fs of the Seas! Only 550Hz! Yeah, the RS180s start breaking up around 2KHz. Thanks, man. 1800 it is.

[alann]

> Hey, you're right! I forgot to check the Fs
> of the Seas! Only 550Hz! Yeah, the RS180s
> start breaking up around 2KHz. Thanks, man.
> 1800 it is.

Look real nice and some funny lines as well. I did get a laugh at the becoming single comment. Yesterday I knew that my RS 12HiFi would be delivered and my wife was home. Lucky that she went to the store when the brown truck pulled up.

Just a thought on the impedance compensation, if all the drivers are zobeled so the impedance is flat the system impedance may go to low. You might not want to pull the impedance all the way down with the zobels. Just a thought that might help. And who could blame the Noid?

[hongrn]

Thanks Alan. I take note of the zobel. I think you got the same philosophy I do: better ask for forgiveness than permission :-)

Hong

[celeste]

Now now boys. At best that is only a short term solution. Do really believe she doesn't know when something new comes into her house? Way better to give her something from time to time in exchange , you might be supprised what a day at the spa might get you , but you have to do it from the love in yoiur heart , not hoping to get something in return.

all the best
Celeste
Mama is not that dumb and she doesn't care for you acting like she is.

> I think you got the same philosophy I do:
> better ask for forgiveness than permission
> :-)

> Hong

[alann]

> Now now boys. At best that is only a short
> term solution. Do really believe she doesn't
> know when something new comes into her
> house? Way better to give her something from
> time to time in exchange , you might be
> supprised what a day at the spa might get
> you , but you have to do it from the love in
> yoiur heart , not hoping to get something in
> return.

> all the best
> Celeste
> Mama is not that dumb and she doesn't care
> for you acting like she is.

I appreciate your point of view but in “our” household we each have made financial decisions that that control each of our expendable income. In her case she needed a new car. I could not get her to look at Honda or a Mazda and the like. She had to have a Volvo and not a little one. You should see her go through the wah, wah, wah when it is time for her to make the payment. I drive a $12K econo bucket and after I make my payment I have $300 extra bucks compared to her payment. Funny how people make decisions that are supposed to make them happy but in the middle and long run they don’t so they go wah, wah, wah, some more.

So if push comes to shove for me speakers come first, the chips can fall.

I don't mean to argue with you but thats how it is on this end.

[cjd]

> Just a thought on the impedance
> compensation, if all the drivers are zobeled
> so the impedance is flat the system
> impedance may go to low.

Eh... my experience is that the zobels help keep impedance UP because you don't have to use transfer functions that are as crazy at the knee.

I've experimented with modeling my 3-ways without all the impedance compensation, and it is definitely preferred to go with it. And they have a zobel on woofers, mids, and tweeter, plus the impedance bump at Fs has been flattened.

C

[brianwalter]

He has a fair amount of experience with the RS drivers. He is also correct in suggesting that you read up on HTGuide Forum, especially the Modula MTM thread. I also have some RS180's and RS10HF subs and I'm still trying to decide if I want to go with an MT or MTM with the RS10HF. I asked for input into this on the HTGuide forum and was basically told that if I went with the MTM, I should use 2 - RS10HF per side to keep up with the pair of RS180's. I did some number crunching, and they were correct, you would need 2 if you want the max spl of the RS10's to equal or exceed the RS180's.

Are you planning to power the subs separately from the MTM or is this going to be a passive 3-way? With the sensitivities of the drivers, you would probably be better off going active between the sub and mtm.

I don't know how much modelling you have done with the RS10JF, but if you go with a ported design, the port ends up being really long. I personally think it lends itself more to a sealed design.

Brian Walter

[alann]

> Eh... my experience is that the zobels help
> keep impedance UP because you don't have to
> use transfer functions that are as crazy at
> the knee.

> I've experimented with modeling my 3-ways
> without all the impedance compensation, and
> it is definitely preferred to go with it.
> And they have a zobel on woofers, mids, and
> tweeter, plus the impedance bump at Fs has
> been flattened.

> C

I understand that too much bending at the knee can cause impedance dips. In 3-ways or when using dual mids especially if in parallel the impedance can go low. If the zobel makes the driver have flat impedance above resonance sometimes that pulls the completed system impedance to low. I was hinting at moderation. Sometimes the impedance can be reduced in the crossover region but allowed to gently rise above the crossover region.

If a woofer was crossed at 300 Hz the zobel could use a cap value large enough to flatten the driver’s impedance through the crossover range and a larger value resistor that required for flat driver impedance. I wasn’t suggesting skipping the zobels just suggesting that if system impedance gets low the zobels could be adjusted so there is a bit of compromise.

[paul_n_oneal]

I have the RS225 8" in a vented cabinet crossed at around 230hz and they rock nicely with clean, tight, accurate bass. I have my RS150 in a sealed cabinet and it does pretty well too. Box tuning ended up being about 95hz on the sealed and around 25hz on the RS225s. I haven't tested the 225s on HT use yet, but they sure do rock on audio. Cheers, Paul.

[celeste]

Hi Alan ,
your not arguing , your providing details that were not even alluded to in earlier posts. the problem is still selfish partner , just a different partner. That is a situation I am most familiar with. Mine insisted on driving ALFA's , owning a thoroughbred and keeping a greenhouse full of orchids. Yet becomes incensed when her partner pulls her racing kart out to the barn and races for a season on less then a years board for the horse. Go figure.

All the best
Celeste