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IMF transmission line alternatives?

T

timkk

New Member
I know these are great speakers but is there any other company that makes better transmission line speakers on par or better to IMF's both vintage and modern (reasonably priced)?

The best reasonably priced modern speakers I could find are IPL's S5TLs http://www.iplacoustics.co.uk/S5tl Kevlar 2.htm for about 800GBP.

They go pretty low down to 22hz but there is no measurements on the website. They claim +-1dB between 250hz-20khz

I'm specifically looking something that beats at least IMF TLS80 MK2 in terms of extension and sound linearity which is pretty impressive (http://www.imf-electronics.com/Home/imf/speaker-range/reference-speakers/tls80) . Any other vintage that can beat IMF TLS80 MK2 and higher?
Don't have to be transmission line if it's better but I don't see non-TL speakers can match these TL speakers.
 
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Interestingly Martin King wrote that with a 8" or better driver there is no advantage betwixt a TL and a BR box.
Something about a TL being basically a BR in disguise.
Although beyond 8" a BR IS superior and much easier to model and fabricate. But then what would he know about it :D
 
bare said:
Interestingly Martin King wrote that with a 8" or better driver there is no advantage betwixt a TL and a BR box.
Something about a TL being basically a BR in disguise.
Although beyond 8" a BR IS superior and much easier to model and fabricate. But then what would he know about it :D
Click to expand...

Really? Link? Show me BR designs which have frequency response graphs better (flatter and digging deeper) than TL speakers - with prices. Let's say for example IMF RSPM 17hz - beyond audibility as per imf's website. FR graph http://lh3.ggpht.com/_z8y2HWwyn58/SgM_QeZWiCI/AAAAAAAAAzI/CmeXj_7PkVQ/s800/rspmmkivgraph2c.jpg
I find impossible to find BR designs that compete with TL speakers either modern or vintage at similar price point levels. I'd like to be proved wrong.
Latest JBL M2s seems to perform slightly better but it's like 20k$????!!!!
http://www.avsforum.com/photopost/data/2172813/9/91/91849f4f_Tech_R5.jpeg
 
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timkk said:
Really? Link? Show me BR designs which have frequency response graphs better (flatter and digging deeper) than TL speakers - with prices. Let's say for example IMF RSPM 17hz - beyond audibility as per imf's website.
Click to expand...

It's easily enough done; in 1976 I built a pair of Hoge's Big Boxes which had better objective bass performance than the IMFs you refer to.



 
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timkk said:
but that's just a sub? ;).
Click to expand...

I took you to mean (among other things) you're skeptical that vented boxes can equal TL performance, I demonstrated they can. Perhaps I misunderstood you.

If you're keen on TLs I suggest you investigate the Van L Silhouette, a modern TL 2-way made in Chicago that is possibly the best cone-dome type speaker I've heard, a rival to the Harbeths. The speakers also look gorgeous and the price is reasonable.

My opinion.

http://www.vanlspeakerworks.com/silhouette.html
 
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Have you listen to a pair of IMF Mk IV?

I really don't think their that good at all and Im sure there is plenty of speakers that sound better. I find them severly lacking bass at lower volumes and realy just don't get it. The only time I can get the bass responce is when they are cranked up. My JBL L250s blow them out the water in my opinion.
 
Side by side comparison

These are RSPM MK IV's that were upgraded at a dealer to have mostly Improved version drivers. Compared to the factory Improved RSPM IV's, these still have the original Celestion HF1300 tweeter, which they may not have upgraded due to the different way the tweeters are mounted in the cabinet.

IMG_1991_zps880fefa9.jpg
 
timkk said:
I know these are great speakers but is there any other company that makes better transmission line speakers on par or better to IMF's both vintage and modern (reasonably priced)?

The best reasonably priced modern speakers I could find are IPL's S5TLs http://www.iplacoustics.co.uk/S5tl Kevlar 2.htm for about 800GBP.

They go pretty low down to 22hz but there is no measurements on the website. They claim +-1dB between 250hz-20khz

I'm specifically looking something that beats at least IMF TLS80 MK2 in terms of extension and sound linearity which is pretty impressive (http://www.imf-electronics.com/Home/imf/speaker-range/reference-speakers/tls80) . Any other vintage that can beat IMF TLS80 MK2 and higher?
Don't have to be transmission line if it's better but I don't see non-TL speakers can match these TL speakers.
Click to expand...

timkk said:
Really? Link? Show me BR designs which have frequency response graphs better (flatter and digging deeper) than TL speakers - with prices. Let's say for example IMF RSPM 17hz - beyond audibility as per imf's website. FR graph http://lh3.ggpht.com/_z8y2HWwyn58/SgM_QeZWiCI/AAAAAAAAAzI/CmeXj_7PkVQ/s800/rspmmkivgraph2c.jpg
I find impossible to find BR designs that compete with TL speakers either modern or vintage at similar price point levels. I'd like to be proved wrong.
Latest JBL M2s seems to perform slightly better but it's like 20k$????!!!!
http://www.avsforum.com/photopost/data/2172813/9/91/91849f4f_Tech_R5.jpeg
Click to expand...

I have a question, What is the point of this thread?
 
bare said:
Interestingly Martin King wrote that with a 8" or better driver there is no advantage betwixt a TL and a BR box.
Something about a TL being basically a BR in disguise.
Although beyond 8" a BR IS superior and much easier to model and fabricate. But then what would he know about it :D
Click to expand...

The advantage of a T-line over a ported enclosure is the absorption of the back wave.
Eliminating standing waves and internal enclosure reflections on the back of the cone is the goal not just low bass.

There are many modern drivers that outperform the drivers used in the IMF designs. :)
 
4-2-7 said:
Have you listen to a pair of IMF Mk IV?

I really don't think their that good at all and Im sure there is plenty of speakers that sound better. I find them severly lacking bass at lower volumes and realy just don't get it. The only time I can get the bass responce is when they are cranked up. My JBL L250s blow them out the water in my opinion.
Click to expand...

I haven't had a chance. TLS50's were my first IMF TL speakers I could listen to which impressed me. I thought they didn't lack any bass.
 
Tom Brennan said:
It's easily enough done; in 1976 I built a pair of Hoge's Big Boxes which had better objective bass performance than the IMFs you refer to.
Click to expand...

A bass reflex enclosure and the transmission line differ in the quality of bass sound they produce. A BR box rolls off at 12 dB/octave and has a "ringing" type of bass response. The TL bass rolls off at 6 dB/octave which is an indication of the non-resonant bass that TL is known for.

The Hoge's Big Box shows the 12 dB/octave roll off typical of a BR enclosure. It may measure objectively equal or better than a TL box, but the non-resonant character is NOT there. However, I must admit that different people has different preference in sound. The TL sound may appeal to listeners of classical, vocal or jazz music for tight, flat response bass. The BR sound may be preferred by listeners looking for a boomy bass for rock or theater sound effect. The final choice is very subjective.

Let us hear from Dr. A. R. Bailey on his objective in designing the Transmission Line Enclosure and why he called it as such.
Bailey said:
By far the largest number of current loudspeaker cabinets are based on the" bass reflex" cabinet design'. (This is shown in Fig. 1 as a sectional view) This cabinet appears to have only a relatively short path-length between the back and the front of the cone and would therefore be expected to give relatively poor l.f. response. In fact the response at low frequencies can be quite large, this being due to the cabinet having a Helmholtz air column resonance at about the lowest frequency being reproduced. In the reference given previously, the theory is well explained.

Unfortunately, this resonance in the cabinet causes coloration in the bass output of the system. This “ringing" of bass transients can be very noticeable, particularly on such instruments as string bass.

In addition the cabinet itself is frequently unlagged and consequently the sound is still emerging long after the original signal has stopped. Very heavy lagging is necessary to stop this effect and in so doing the cabinet "Q" is reduced so that the bass reflex action is lost.

Sine wave testing does not necessarily show up the defects of a speaker system. Rapid cut-off at the edges of a flat response can make it sound far worse than a slower rate of fall at the edges of a system with apparently a poorer bandwidth.
Click to expand...

By the way, many of those so called "modern" or "mass loaded" transmission line are actually a variation of the BR box with 12 dB/octave roll-off. Only 2 stuffing materials have been shown to work well in TL, the long fiber wool as specified by Bailey and the open cell foam chosen by Bud Fried.
 
Tom Brennan said:
I took you to mean (among other things) you're skeptical that vented boxes can equal TL performance, I demonstrated they can. Perhaps I misunderstood you.

If you're keen on TLs I suggest you investigate the Van L Silhouette, a modern TL 2-way made in Chicago that is possibly the best cone-dome type speaker I've heard, a rival to the Harbeths. The speakers also look gorgeous and the price is reasonable.

My opinion.

http://www.vanlspeakerworks.com/silhouette.html
Click to expand...

I see that Gary Van Slooten is now using the Misco line of drivers.

The original Van L Quartets used the dual voice coil Gefco composite cones in his designs which are no longer available.
 
JimPA said:
The advantage of a T-line over a ported enclosure is the absorption of the back wave.
Eliminating standing waves and internal enclosure reflections on the back of the cone is the goal not just low bass.

There are many modern drivers that outperform the drivers used in the IMF designs. :)
Click to expand...

What would you recommend that will outperform IMF's for about 2-3k$ (can be used)?
 
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