Were Renaissance 90s the best Infinity?
- Thread starter Endzone
- Start date
bastek
Well-Known Member
The Sigma has 3 large separate crossover boards for low (12" woofer) , mid-bass (6.5" mid-woofer), and mid-high (Emim-Emit) sections.
Only the low bass x/o board has electrolytics in parallel with the woofer.
Measuring with a L/C meter you should see a mixed value of around 4.5mH and 10uf across the low posts with the jumpers removed. The values change if the caps need replacing. Mine are within spec, i measured them out of the circuit board. For the high section i see 130uf and .8mH.
I'd like to verify these capacitance-inductance measurements with other Sigma owners to check for x/o variations.
Only the low bass x/o board has electrolytics in parallel with the woofer.
Measuring with a L/C meter you should see a mixed value of around 4.5mH and 10uf across the low posts with the jumpers removed. The values change if the caps need replacing. Mine are within spec, i measured them out of the circuit board. For the high section i see 130uf and .8mH.
I'd like to verify these capacitance-inductance measurements with other Sigma owners to check for x/o variations.
Endzone
Active Member
According to this schematic the resonant frequency of C8/L7 is 245Hz. This would give maximum aplitude to the mid-bass at this frequency. The resonant frequency of C7/L6 is 317Hz. This would give maximum current flow at this frequency. Is this correct? I'm thinking L8 is a high frequency or transient attenuator. I don't know where the 3dB rolloff points are, but I'm guessing that max amplitude is between 200 and 350Hz. Am I correct?
Endzone
Active Member
A pair of SM-150s are still in the Dallas Craigslist, but after listening to my speakers the way they were 20 years ago, the bass drum there is just so booming. They were good speakers for $400, but I don't think I want to own them again. Plus they weight 70 lbs. Also if they blew a tweeter, I don't know if they're still available.
This system here is a Kenwood M2A amp and the equalizer was set with a TEF Analyzer for flat response on all frequencies. I would not use an EQ again, but at the time it was the thing to have. The video is very strange I know (this is at a friend's house with a wedding the next day) but listen to how booming the bass drum is. I wonder what this same song would sound like on a Renaissance 90.
SM-150s almost brand new 20 years ago:
http://www.youtube.com/watch?v=whAD5mnstI0
This system here is a Kenwood M2A amp and the equalizer was set with a TEF Analyzer for flat response on all frequencies. I would not use an EQ again, but at the time it was the thing to have. The video is very strange I know (this is at a friend's house with a wedding the next day) but listen to how booming the bass drum is. I wonder what this same song would sound like on a Renaissance 90.
SM-150s almost brand new 20 years ago:
http://www.youtube.com/watch?v=whAD5mnstI0
rabbit
Well-Known Member
I have some photos of the Ren 90 X-over. Rough and ready IMHO.
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Inspiribomb
Enjoy the journey
Rabbit, thank you very much for the Ren crossover pictures! I haven't yet pulled mine apart. Those do look a bit unsightly, and I can imagine that they could benefit from a rebuild/refurb with high quality components.
Looks like there are multiple boards with crossover components on them.
Looks like there are multiple boards with crossover components on them.
heck, for infinities those XOs look gorgeous! i'm not sure i'd bother with the electrolytics (YMMV, of course), but you can do better than the solens if you're ready to drop some coin.
The Ren crossovers are works of art compared to earlier Infinity crossovers. I got hold of a back up set of Ren crossovers and was just amazed how much nicer they were than, say, a Q2 or RS-1 crossover. The QC on early Infinity crossovers was really appalling.
Dvaid
Maxamillion
Super Member
Endzone
Active Member
That is horrible. That just shouldn't be in a pair of $4000 speakers. No excuse for that.
What exactly do you find issue with? The construction of the crossover? The choice of parts? The design itself? Just curious.
Endzone
Active Member
Well, they say a picture is worth 1000 words, but I guess I don't have 1000. I'm not an engineer so the crossover frequencies and bandpass for that particular speaker (mid-bass) are fine with me. So I'm not qualified to comment on the design--I'm not an engineer or speaker designer. But of course it's a rather simple formula for determining the resonant frequency of LC circuits. 1/6.28FC = 6.28FL where F is the frequency, C is capacitance and L is inductance.
Nope don't care who manufactured the parts. I don't know a good electrolytic cap mfgr from a bad one.
BUT, the construction, yes I have a serious problem with that. First of all I would like to see the components mounted on a PCB with traces rather than point-to-point wiring. The cables should be attached to post or else hard wired to a PCB via through holes. The caps should not be stacked on top of each other and held down with glue. They should all be mounted on a PCB and maybe secured with tied wraps. The leads coming off the inductors look hideous and they seem to be touching the case of the inductor. This looks at best like a build up in the research lab rather than a production run. I can't believe this came from the factory this way. This must of been somebodies home brew modification? Replacing parts would be difficult with this "rat's nest".
Infinity probably didn't give a rat's nest about how the crossover network appeared until they morphed into Harman Kardon, a company who's bottom line was profit and probably an effecient quick "industrialization" method of production of crossovers via a pcb board. And more than likely didnt give a rat's nest as to whether someone could easily replace a capacitor or two in the distant future.....actually I'm a klutz with the soldering iron but find easier to replace parts point to point than on a circuit board
actually I'm a klutz with the soldering iron but find easier to replace parts point to point than on a circuit board
+1. Especially as part sizes can change quite a bit over time..
I didn't see that wiring between the capacitors and the right inductor, that is a little ugly. Pretty sure that's all factory, the inductors look familiar and Infinity has been using T.I. electros since the early days. As long as everything is safe enough and secured down by glue or screws or whatever, I'm personally OK with it, but then again I "grew up" on vintage Infinities. We fans, especially those of the older stuff, seem to have a reputation as tinkerers, since a lot of these speakers often need more than just a little upkeep, whereas a lot of people frown on speakers that aren't more plug-and-play (some of these people tend to discount vintage speakers in general). I think this makes us a little more forgiving of Infinity's QC and other soft spots, but it is worth noting that a lot of companies probably wouldn't have let that one out the door.
rabbit
Well-Known Member
A lot of Infinity crossovers were built like that unfortunately
It's like Infinity got people down at the local tech college to practice their soldering skills by building the crossovers for them 
I prefer the crossovers in the RS-4.5's. It's a modular PCB construction and you can access it without having to remove the speaker drivers, nor are the components exposed to the high pressures inside the enclosure
rabbit
Well-Known Member
Resonant frequency of a series or parallel LC circuit is
1/(2 * pi * sqrt( L * C))
Note that the other half of the crossover is mounted on a PCB, but like I said it is rough and ready and works for all intended purposes. But I agree for the money they were charging they could have done a lot better job
I had to rewire my RS4.5's once because the monster cable had oxidized, and I did a lot better job of it too !!
rabbit
Well-Known Member
bastek
Well-Known Member
As DIYer i only care about the placement of the inductors. They shouldn't be too close to each other facing in the same direction. In this case they are shielded so they look OK to me. Also iron core inductors can produce ringing in the mid-high freqs, so air core is preferred.
No problem with hot glue or a bunch of caps glued together, but a small piece of plywood-mdf board would hold and look better.
No problem with hot glue or a bunch of caps glued together, but a small piece of plywood-mdf board would hold and look better.
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I don't know the details of the acquistion of Infinity by Harman Intl. If someone knows where this can be found I would appreciate it. However if Infinity had been more attuned to the fact that even their "bottom line was profit", is it possible they would not have been assimilated? Sorry for the off topic query. "Crossing over" from Ren90s to this may require a modified "capacitance" for change.
Any ideas on where to find info regarding T.I. capacitors?
The only (minor) references to them that I can dig up are related to being used in Infinitys, and certainly nothing about them being available. Assuming that one day my crossovers will be candidates for being rebuilt, it would be good to be educated about what was stock.
Thanks- Herb