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IMF owners thread!

JimPA said:
I.M. Fried commented about the tube in one of the writings that SimplySound and I copied and paste earlier on this thread.

It is unclear to me if R.Wright used T-line loading for the mid bass driver in any of his TDL designs.

I.M. Fried did use T-line loading in many of his 6.5" mid bass enclosure designs as I previously stated with Fried Products.

An 18" tube theoretically could go down to 270Fs in a T-line.
There would have to be a line terminus opening at the rear of the tube.
Click to expand...

Back on point, my only concern is the IMF Super Compact I or II series, no other brands or no other models. Does the IMF comment copied & pasted relate specifically to the IMF Super Compact ? And, what post # is it ?, please, so we may read it. What is the meaning of the IMF literature printing stating the IMF Super Compact "mid range is isolated in it's own short transmisson line" ?
 
luvmusik said:
Back on point, my only concern is the IMF Super Compact I or II series, no other brands or no other models. Does the IMF comment copied & pasted relate specifically to the IMF Super Compact ? And, what post # is it ?, please, so we may read it. What is the meaning of the IMF literature printing stating the IMF Super Compact "mid range is isolated in it's own short transmisson line" ?
Click to expand...

IIRC Fried was referring to the tube enclosures used in the past as a general statement and not referring to any particular model of speaker.
 
When I change my mids I can take a look inside, but I don't want to take out all the foam from inside the cabinet. It may be a long time until I can delegate the minor project, it has low priority so far.

If the midrange tube foam comes out easily I can see if tube is glued to back wall, which would make IMF's literature really odd, & seemingly wrong, if not vented. But we have seen some IMF printed literature already that was sorta open to interpretation as either vague or completeley contradicting itself with opposite details. If the tube is vented or does not terminate, and rather is open to back wall space, then it makes more sense.

Don't know if there is any actual "vertical channel" constructed from wood back there, or just a cavity vertical space down & out bottom combining with woofer out underneath to front vent. It is possible strips of vertical foam may be in place to create a vertical channel downward, with maybe the entire bottom horizontal foamed entirely, for resistive loading. The midrange is off-center from the woofer, so foam "channeling" is a possibility, as a seperate channel downward for the midrange.

I quickly checked thru AK threads & some fellows replaced Super-Compact drivers and crossovers, but didn't see any fotos of a total refoam or stripped cabinet inside.

There is a foto on the web showing bare stripped cabinets open to see, and it does not seem that any seperate wood vertical cavity chamber is there near the back wall (and hard to tell if so, too), unless it was removed & photographed -leading to believe, if it is a midrange T-line as IMF states, then it may be channelled from vertical foam strips or an open back wall chamber down to the bottom front vent. I dunno.

Maybe someone has yanked all the foam out of theirs to get a looksee.
 
Hi, Luv's after looking at your #22 post concerto vs super compact, it seems looking at the IMF publication on compact and super compact, it is the compact who have the semi transmission line because considering the 6 1/2" has a mid and have a tube open inside the enclosure,that what they talk about,not the super compact.The SC habe a close tube,look by yourself and read the text you will understand,Yvan.
 
Hi Yvan, Sorry, no disrespect, but look again at the text 3rd paragraph down... quoted again = the SUPER COMPACT "mid range is isolated in it's own short transmission line", and the diagram is the one all way at bottom (not the compact discussed at top in first 2 paragraphs with top picture). The bottom diagram supports their description, following the midrange tube to the rear as stated in many of my posts, now redundantly. The SUPER COMPACT does have an IMF-printed response of 30 to 20,000 Hz. A fellow here on AK measured his to confirm that & had nearly identical frequency response graph curve, although his was digitalized. Of note is 30 Hz is achieved -10db. The brochure is termed "compact brochure" by whoever titled his link of that brochure, but you will see reading closely - the brochure top is about the compact, and from paragraph 3 down to bottom diagram is the SUPER COMPACT we only were discussing, and again here; that brochure may have included other models besides these 2 as 1 page only is shown, sorry.
 
Hi,Luv's if it was the case the SC should have an extra port not considering the opening at the bottom. They can not use the same line mixing mid frequency and woofer frequency.Yvan
 
Hi,bizarre plus the speaker's is only 11 3/4" deep,if it was the case using the bottom opening you will see a separation at the bottom, or just putting your hand at the foam down there you will fell a separation,but I doubt it is the case.The als and tls 50 have a longer tube for the mid,Yvan
 
I tried to attach the brochure here in this thread for all to read paragraph 3 downward, but the site won't allow me because it says it's already linked on the other thread. I'll try a web link instead at bottom of post here, if that works, I hope.

If going down to very bottom of spec sheet you will also notice the model you are referring to (Compact II) is a 2-way design, and thus, of course has no midrange tube, only a general port for the cabinet. That model's woofer also covers it's midrange and only extends to 35 Hz, not 30 Hz as in the model we are discussing -the Super Compact (series I and II).

I believe you are mixing the two models...please reread my earlier posts about vertical foam strips constructed into vertical channel to isolate the midrange and another seperate channel to isolate the woofer. They may have resistive-load line tuned the reflex cabinet design for the woofer in isolation with also seperately isolating a down-vertical and out-forward bottom channel for the midrange seperately. A t-line chamber cavity does not have to be constructed of wood on all 4 sides - different isolating materials can be use to establish the transmission line - the resistive loading is important.

But, again...IMF prints the Super Compact "mid range is ISOLATED in it's own short transmission line". They can use one vented bottom port for both the individually isolated bass-reflex woofer combined with an individually isolated tuned t-line for the midrange -it's what the entire cavity looks like that's important from the top rear back wall down to bottom and out. If tuned properly and resitive-loaded -both low & mid frequency drivers can exit the same front vent if they are properly isolated apart from each other from path origin to final venting out. That "tunnel" can be made with foam vertical channels or other materials.

If someone has a factory-original Super Compact that they gutted to bare bones, we would know the answer, and then need not speculate on the actual construction of this midrange t-line. Probably someone has done that beyond replacing drivers & crossovers. IMF printed this information, not me, but some are wondering about the actual physical configuration of that mid-range transmission line.

I'll try posting a web link here for that brochure, so folks can read IMF's information, see the bottom speaker diagram and very bottom page specs, along with 3rd paragraph from top discussion of the Super Compact midrange t-line. Hope this link works.

http://p10hifi.net/planet10/IMF_compact_brochure.pdf

I think the great minds at IMF were careful in their reknown SC design -it was their best seller. The discussion may want to be not about IF a midrange t-line DOES exist, taking IMF's word as truth, but rather - as originally asked - how is it constructed, and what does it look like internally, for IMF's exact meaning of this t-line physically.
 
Again, looking carefully at very bottom speaker diagram in link shows midrange tube extending rearward PAST an initial "wall" of either wood or foam or other material into a airspace cavity between that "wall" and the very rear final wall. It appears there are 2 rear walls with an air cavity (or foam region) inbetween those 2 walls. The initial wall may very well be consrtucted of a sheet of foam, of course the rear wall is particle-board wood. Keep in mind the diagram illustrates these partitions as "cut-aways", otherwise they cannot be visualized properly. The diagram is zoomed well to see that, so my original question remains, as per what IMF prints in paragraph 3 from the top.
 
:beerchug:
Cheers, Yvan, we'll figure it out eventually. I don't want to strip my cabinets bare because my skills are poor & I may ruin the Super Compact Mk II. But, in time someone will post who has gutted their factory-originals down to bare bones (maybe a refoamer project) and can inform us of this midrange transmission line configuration in detail. We never know, maybe there are some narrow free-air space cavities or foamed-chamber regions between the wood boards, all in good time; nice exchanging with you - Frank
:beerchug:
 
Hello all:)
Just wanted to share my happines with you:).
Finally managed to buy a very rare pair of
IMF RSPM MKIV Improved. They are on their way from Germany
to UK as we speak.
Speakers will arrive tomorrow morning.
Can't wait to have a first listening session.
I'll upload some pictures, if somebody tells me how to do it:)
 
Congratulations Luker ! We share in your excitement. Let us know how you like them. I use a high damping amp on my MK IV standard, highly recommended to better control the woofers. We are in great anticipation to learn of your impressions !
 
Thanks luvmusik:)
I'll let you know, as soon as i get them home.
This is gonna be my second pair of IMFs by the way.
I already have Pro Monitor mkIII.
It's gonna be interested to compare these two models and
see, if RSMP MKIV Improved are really improvement over Pro Monitors.
 
That will be one of the greatest runoff comparison tests ! Very interested in the final listening results.
:lurk:
 
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