IMF speakers - TLS80 vs. RSPM IV

cdfac

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I really don't know much about IMFs, except that they are well regarded. Can someone explain to me the difference between the TLS-80 and the RSPM MkIV, and how they fit into the hierarchy in general? My understanding is that they were both TOTL in their own way and they seem kinda similar, but I don't pretend to understand the model structure very well. Any input is appreciated!
 
I like to be broad-minded about assigning TOTL designations. If it was the pinnacle in a lineup at the time of it's release, it doesn't matter if something later on topped it.

At least that's what I tell my SX-1250...
 
The TLS 80 is a transmission line enclosure and has the KEF B139 woofer, KEF B110 mid and Celestion tweeter and super tweeter from what I recall.

They sounded great but need a big amp as they are inefficient.

I had some KEF Bailey design Transmission Lines and they sounded good, the IMF's were a step up from them.

Well worth looking at IMO.

They will have that classic British sound, laid back and sweet in the mid range with very extended bass. Certainly not your forward boom tizz speaker sound.
 
thanks for the info. the wording on the IMF site is subtle, but it seems that the TLS80 was the home version of the Professional Monitor, which itself was a slightly less extravagant version of the RSPM. that being said, i found a site where a couple of guys had preferred the sound of the TLS80-II over the RSPM-IV because of the crossover differences. it seems that the real top dog is the SACM, which is basically just a fancier layout of the RSPM with perhaps some crossover differences thrown in.

the SACM, borrowed from Stephane who i think runs the IMF site:
sacm3.jpg
 
Both the TLS-80 and RSPM sound extremely detailed, have very natural sounding low end (down to 16hz) and are quite harsh in the midrange. If a mix has problems in the midrange these babies will reveal all and believe me with bad productions that sounds pretty horrible. Besides that they're huge and won't fit into a lot of living rooms so I guess TLS-80 and RSPM are not for everyone. Amazing speakers though. The RSPM is much more rare then the TLS.

I own two pairs of TDL transmission line speakers (an IMF offspring), my dad a bunch of pairs of IMF speakers including the RSPM, ALS40, CM3 and CM2. Me I prefer the TDL's as those are not as agressive in the midrange but do have the detail and wonderous low end that comes with transmissionline speakers. The TDL Studio 3 reach as far down as 20hz which really should be low enough. The smaller studio 0.75m go down to 30hz which is pretty good for a floorstanding speaker that's only 67cm high. I absolutely love 'em!

These are the TDL's...

meertdl.jpg
 
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...and are quite harsh in the midrange.

interesting, i hadn't heard that before. i figured they'd be ruthless at the very least, which is something i'm used to.

i know where an RSPM IV is for a pretty good price (i think), but i'm not sure i have the room, and shipping might be a bitch. i have the extra electronics for another nice setup though... :scratch2:
 
I have a pair of RSPM IVs and "harsh" is hardly the word I would use to describe them. Coming from a mostly-Infinity background, I consider them much more laid back than the EMIMs. I like them quite a bit, but they are definitely a change from the Infinities.

David
 
I have a pair of RSPM IVs and "harsh" is hardly the word I would use to describe them. Coming from a mostly-Infinity background, I consider them much more laid back than the EMIMs. I like them quite a bit, but they are definitely a change from the Infinities.

David

Got any detailed pics of the RSPM IV'S?

Yank
 
I have a pair of RSPM IVs and "harsh" is hardly the word I would use to describe them. Coming from a mostly-Infinity background, I consider them much more laid back than the EMIMs. I like them quite a bit, but they are definitely a change from the Infinities.

David

AHA, a man with whom whose taste i can relate! tell me more, if you don't mind. i guess the best point of reference would be the RSIb's.

i've been intrigued, if not completely won over, by the different sound of my Thiels, and i think it's good to get outside of the box a bit. the RSPM seems like it might be a good match for my Yamaha monoblocks, which are 100wpc Class A.
 
Got any detailed pics of the RSPM IV'S?

Yank

Here are a couple. The first one is next to a 60 inch rack, to give you some perspective on the size of them. Not particularly big in Infinity terms, but pretty big relative to most of the speakers out there - heavy too. The second picture is without the grill, and the third without the grill or the bottom panel covering the adjustment pots.

I'm not terribly good at describing the characteristics of speakers. I guess I would describe the IMFs as "lush", while the Infinities are "detailed". For certain types of music (big orchestral pieces), the IMFs sound really smooth and just envelop you in sound. For jazz, female vocalist, piano, etc. (where I really want to focus on the details), I prefer the RS-1s. Hope that helps a little, Chris. They really are extremely pleasant speakers to listen to, and worth trying if you have access to a pair.

David
 

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that does help, David. i might just give them a try - i think i can take care of shipping now very inexpensively. i wonder if recapping the XOs would decrease the lushness in a good way...:scratch2: is the XO behind the front panel or in the back?
 
Don't know what your situation is, but I suggest you consider just going and getting them rather than having them shipped if that's possible. No one is going to treat them better than you will, and while it may be costly to take the time to go get them, shipping them properly will be too. And if you go get them, you can make sure they work properly before you take them.
And I have to say that harsh is not a word I would have thought to use with the TLS 50s I used to have.
 
Don't know what your situation is, but I suggest you consider just going and getting them rather than having them shipped if that's possible.

well, when i say "inexpensive shipping" i mean using an AKer via the Pony Express :D
 
cdfac:

I do not know the position of the crossovers in the monitors, but the ones in my TLS80s were simply glued to the foam back behind the B139. I think that I may try and tackle the re-cap this summer. As you can see in the next post (hopefully), the adhesive bonded with the foam and it now covers the bottom of the PCB.
 

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Chris,

I've never opened mine up, so don't know where the crossovers are, but I kind of assumed they were in the bottom of the cabinet, since that's where the tone controls are.

David
 
wow, looks like a tricky XO to work on - looks like no labels on half the stuff and no schematic readily available (AFAIK).
 
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You may find the schematic you are looking for here:

http://www.imf-electronics.com/

Got the photo of the bottom of my TLS80 crossover to load. Hopefully you will not have to deal with this.
 

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