Kappa 8 Polygraph Midrange
- Thread starter tubed
- Start date
Register to hide this ad
VintInfinity
Tactophonic
As you can see in my avatar, the PolyGraph Mid-Bass coupler is much bigger than the Polydome and plays a different range. So, no.
Iagent
Rick
There would be a gap in your spectrum of sound. Just like as if you used an Equalizer, and slid about 6 of the 31levers to zero in the midbass section.
Very very no good.
Edited:
Correction, I was thinking that you were deleting the polygraph. Deleting a dome would obviously cause a loss of the higher end of the mid.
Very very no good.
Edited:
Correction, I was thinking that you were deleting the polygraph. Deleting a dome would obviously cause a loss of the higher end of the mid.
VintInfinity
Tactophonic
I think the domes on these are really "fast" musically, so things like acoustic guitar and chimes and percussive strings seem to jump out more naturally and quickly than some cones do. A faster attack and more natural decay that resembles a real instrument more closely.
VintInfinity
Tactophonic
They don't really move much, so I guess that is how they do it. The mid-dome feels like it isn't even working you if touch it, but the mid-bass makes some stronger vibrations...
I can only imagine what EMIMs and L-EMIMs are like.
I can only imagine what EMIMs and L-EMIMs are like.
Two polydomes just sold on e-bay for 142.00 there are also two polygraphs up for sale ( Of course they are not mine ) FYI Only. I see you handle is Nak Doc do you repair Nak equip??? Just curious as most of my system is the 7 series.
rroobbcc
Active Member
Actually BOTH the Polydome and the Polygraph are "unobtanium" from Infinity. When I damaged one of my Polygraph mid-basses back in 2001, they sold me the cone mid-bass from the Ren90 as a replacement. The Ren90 is an excellent speaker, so I have no concerns about the quality of the driver. However, you do need to enlarge the opening in order for this driver to fit. Instead of cutting, I used a file to slowly and exactly remove just enough material for the Ren90 driver to fit. This still left plenty of material to go back to the Polygraphs if I ever pickup another on Ebay or elsewhere. It was a pain to file instead of cut, but it is worth it for the ability to return to stock (which I do intend to do). Regarding sound differences between the two. I ran with one Polygraph and one Ren90 mid-bass for almost 7 years, before finally putting in the other Ren90 driver when I refoamed my woofers this year (or was it end of last year). I could never tell a difference between the two.
Rob
After doing some reseach on Infinity Classics website,it seems as though the Polygraph driver could be a drop-in replacement for a Polydome especially since the Infininity Systems schematic has the Polygraph driver as its midrange of choice(in this schematic) for the Kappa 7. Kind of strange since I've never seen this design in person.
VintInfinity
Tactophonic
The picture on the schematic is wrong. The Kappa 7 uses the Polydome for mids, and the crossover point for the woofer is higher to accommodate that. The list on that schematic is correct.
In the Kappa 8, trying to use the midbass where the mid should be won't sound right. It reproduces 90-700 Hz, while the polydome reproduces 700-5000 Hz. In the Kappa 7, the polydome reproduces 800-4500 Hz.
In the Kappa 8, trying to use the midbass where the mid should be won't sound right. It reproduces 90-700 Hz, while the polydome reproduces 700-5000 Hz. In the Kappa 7, the polydome reproduces 800-4500 Hz.
The Kappa 7 schematic might have been one of original intent.....I believe the Polygraph mid is being utilized properly in the Kappa 9, crossing over from the mid-bass at 700hz, exactly where the midrange on the Kappa 7 crosses over. It doesnt seem the Polygraph should be doing business down at the 90 hz crossover level on the 8's as it seems to be more of soft dome driver than mid bass. JMHO
VintInfinity
Tactophonic
:saywhat:
rroobbcc
Active Member
Dude... listen...
There is no such thing as a "Polygraph mid". There is a PolyGRAPH MID-BASS, and a PolyDOME MIDRANGE. The PolyGRAPH is ONLY used in the 8 and 9 Kappa as a... MID-BASS. The PolyDOME is used in the 6, 7, 8 and 9 Kappa as a MIDRANGE. In the case of the 6 and 7 Kappa, which does NOT have the PolyGRAPH MID-BASS, the woofer is crossed over at a higher point to handle the mid-bass frequencies.
Sorry, if this sounds a bit condescending, but these other guys have a lot of experience with these speakers and what they are telling you is correct.
Rob
There is no such thing as a "Polygraph mid". There is a PolyGRAPH MID-BASS, and a PolyDOME MIDRANGE. The PolyGRAPH is ONLY used in the 8 and 9 Kappa as a... MID-BASS. The PolyDOME is used in the 6, 7, 8 and 9 Kappa as a MIDRANGE. In the case of the 6 and 7 Kappa, which does NOT have the PolyGRAPH MID-BASS, the woofer is crossed over at a higher point to handle the mid-bass frequencies.
Sorry, if this sounds a bit condescending, but these other guys have a lot of experience with these speakers and what they are telling you is correct.
Rob
It might seem like I'm on a jihad about using the Polygraph as a midrange instead of the Polydome. It actually was just a case of being carried away with wishful thinking that I could use a pair of Polygraphs I have access to, to replace my cracked Polydomes. I was motivated to double and triple check when I saw the Infinity Kappa 7 spec sheet list and picture the Polygraph as what I was hoping to be a possible substitute, not the original driver... especially considering the cost and unavailabilty of the Polydome. Thanks for all the input.
Keep your eyes on e-bay for a pair of polydomes they do come up from time to time and usually go for $75 each if they are in good condition....Once I bought a whole pair of Kappa 6 speakers for $150. Kept the domes and sold off everything else. Ended up making $100 and getting the domes for basically free. Augy
Similar threads
