[gerG]

Hi Irons.

I saw some really interesting woofers at CES that I need to follow up on. Lots of good stuff out there.

That Adire is interesting, but I will never again buy anything with a foam surround. That is an unacceptable shortcut by a manufacturer, imho.

gerG

 

[Irons82]

What's wrong with foam? Just want to let you know that you are missing out. A properly designed Tumult in a sealed box, with 2 of these passive radiators will sound so much better and much much louder than your current set up, with NO distortion. How are low frequency produced? By pushing crap load of air, and the Tumult is the best in business. Try to find any 15" subwoofer out there that can do 34mm linear excursion. That and did I mention, no distortion?

BTW, nice house

 

[zeplin]

Irons82,
i know a certain Velodyne sub that can outperform your sub any day of the week. the HGS 18 (18 incher) i believe it is called! tremendous bass with an extremely flexible rubber-like substance used for the surrounds on the driver. my klipsch rsw-12 has the most accurate, deepest bass i've heard in a long time...also very durable rubber-like surrounds the problem with foam is it is outdated, and like gerG said, it is a cheap corner to cut when producing a speaker. it shows that the company is not there for the search of the best possible reproduction in sound that they can accomplish. it is kind of insulting, they believe and only hope that only people who don't know the difference rubber and foam surrounds will buy them. hence, Bose <<as i gag>>! i have a couple of speakers that have foam surrounds...they are only 4-5 years old and the foam surrounds are already starting to break down. pittiful

 

[Whitebread]

I haven't bothered to read this whole thread, so forgive me if it was already said, but, a tumult in a 3 PR enclosure can give you 130+ db at 40+hz. And it's sounds great!! Hell Stereo tumults would be even better.

 

[gerG]

I have some issues with foam. Perhaps there are different formulations out there now, but my experience tells me the following:

1) Foam rots. I am really tired of throwing away woofers that are still fine in every other respect, but the foam surround has turned to dust. I have numerous drivers (dating back to the late 70's) with rubber surrounds, and they are still going strong. This is especially a concern for outdoor speakers.

2) Foam surrounds generate noise. I have heard this demonstrated, and there is an amazing amount of mid and hf noise generated by those things. It is not a harmonic, so it won't show up in harmonic distortion analysis. Just poor S/N.

3) Foam is unstable with time. I hate when my woofer parameters change after the cabinet is built.

4) As far as I can tell, foam surrounds are simply a cost cutting measure. Last check foam surrounds were about 10% of the cost of a decent rubber surround. It tells me that the manufacturer is cutting cost. Sort of like buying a high performance car and finding that it has the cheapest tires that they could find, and they are welded in place so that you can't change them! Worse yet if they are foam tires.

As far as alignments go, I could have made a lot more racket with these with a bass reflex or PR alignment. Since damping and transient response were a criteria, I ruled those out. Indoors the woofers are faster than the room, so it isn't a big issue. Outdoors, however, there is no room reinforcement or overhang. It is amazing to hear deep bass that can start and stop like that.

Making loud bass at 40 hz is pretty easy. Getting accurate bass at reasonable levels outdoors at 20 hz is a tougher challenge. Try it, it is fun!

One other point of note: I chose the woofer that I did for performance to cost ratio. I have no intention of setting $1000 worth of drivers outdoors to get rained on. My satellites I can stow indoors, but the subs need to be weatherized.

If I had it to do over again (and I do) I would go with a sealed alignment and equalize for flat response. This would yield a smaller cabinet, and pretty similar results. I just wanted to try a bandpass design. It does protect the woofer nicely, but now I have to design against critter intrusion (the things are natural bee hives).


Sigh...time to get back to my real job.


gerG

 

[gerG]

I thought to update my long lost thread.

The Shoguns were doing bad things to my living room. At the same time, I was not happy with the acoustics in there, or the fact that the system was audible from the entire house. My garage is much larger, has block walls, a "lossy" rear wall, and it it's own heat pump (my project summer before last). I lugged the 'guns down here, along with the ADS 1290s, 3 amps, a digital crossover, 2 players, and 60 ft^2 of acoustic foam (for the ceiling mostly) and my test mic. The result is a wonderful listen, for any room.

I am in the process of matching the speakers and the room, but here are the response curves so far. Since the system is tri-amped, I can check each band individually to set crossover levels and match the x-over points to the drivers. The bands are subs up to 80 hz, mid-woofers to 1 khz, and mid+tweet (with a passive in between) above that. Due to the touchy nature of mic placement at high frequencies, I only measure one side for the HF band check. The full up measurement is just that, with all cones/domes talking at once. These are pink noise tests, because I want to see the room interactions. I will begin stalking those next.

I can post pics if anybody is interested. Notice the lower extension of the subwoofers. No wonder I am having structural problems. I am working on a design for a new speaker system with a tall ribbon and a strong bass module. The woofers are 40 pounds each. Still deciding between 1 or 2 woofers per side. I need to see how the garage holds up to the 'guns first

gerG

 

[agile_one]

gerG, you are my hero - sanity is much over rated.

When I saw the photos of your listening deck I was reminded of this old Maxell ad ...

 

[D-EJ915]

gerG, now your avatar is worthy. On friday I played my system at school and shook the ceiling and door in the room I was playing them, from a 10" woofer too!! Anyway...nice job

An audio store near me (Audio Connection) used to have the ad on the side of the building, but they recently painted it over...I was sad when that happened...it was soo cool

 

[averydonovan]

How many cacti have you blown up with those things? Haven't you been getting complaints all the way from Flagstaff and Lake Havasu City everytime you play them? And how many of your neighbors have also had plumbing problems due to your subs shaking their foundations too? You shouldn't have to worry about beehives, the waves coming out of that thing would probably kill any creatures that dare venture inside those subs

Those are some very cool subs, I can only imagine hearing something like that. Nice work

 

[gerG]

Hey Gene, thanks for the blast from the past. I always loved that Maxell ad. It is good to hear that sanity is overated. I am still curious what it would be like.

D-EJ915, my avatar is actually "borrowed" from Bloom County (sorry Berke). It is none other than Milo Bloom experiencing something new called "MTV". I was around at the dawn of MTV. Did you know that they used to play music?

Donovan, lol. No cacti were harmed in the testing of these speakers. I think that saguaros are bass heads anyway. Fortunately my neighbors are far enough away that their water lines are safe. They may spot ground tremor ripples in their pools if they look close, though. You are close to the mark on a side benefit of good subwoofers: scorpions just hate lf vibrations. Now that I have run them out of the house it is time to clear out the garage.

I tweaked some more last night, and discovered something wonderful. The smoother I got the response, the more I turned the volume down. Everything was there with detail and dynamics, so no need for much volume at all. Very headphone-like.


gerG

 

[gsferrari]

I vote this thread : [size=medium]BEST THREAD OF 2004 [/size]

HILARIOUS!!

 

[princeclassic]

you seem to think that all foam surrounds are the same. they definitely are not. a high quality foam surround can last just as long as a santoprene/butyl rubber surround.

high quality foam surrounds like those found on adire audio products are treated so as not to deteriorate over time.

if the adire surround was cheaply made, i don't think it would last too long with a driver capable of 34mm one way excursion.