Chorus II questions

[vnzbd]

Hello all. Today I picked up a very nice pair of Chorus IIs for $325. They have a date on the stickers of 6/20/90. It seemed too good to pass up even though I am not really in the market. I have a couple of questions about them so hopfully the experts can weigh in.

What is the recomended distance away from the wall for a speaker with a passive radiator?

Has anyone put a protective grill on the passive radiator? (why?/why not?)

With a build date of 1990, what is the expected life expectancy of the factory xover?

Thank you and Happy New Year!

[willland]

Great score on the Chorus II's. I was eyeing those also and calculating holiday traffic time from Kissimmee.

I have my Forte's 12 inches from front wall and about 16 inches from side wall in the corners. My Quartet's are at 18 inches and 12 inches. Both have about 8 degrees of toe-in.

Experts please chime in about life of crossovers.

Bill

[vnzbd]

Thanks for the info Bill. I have started with them toed in so that on corner is 9" and the other back corner if 12". I sit about 14' away. Based on your setup I will experiment a little further away.

[USNRET]

Mine were approx. the same vintage and I bought cap kits from BEC but never put them in. When I sold them several months ago to make room in the house I sent along the kit so I can't say what the benefits of a 'renewal' would be. I had mine in a lot of different places from military barracks rooms to a 700 sf mancave, they were VERY forgiving as to placement.

[Video Guy]

Has anyone put a protective grill on the passive radiator? (why?/why not?)

I have seen a forum thread where someone has put a protective grill on the passive radiator but I can't find it at the moment. I believe they bought them from Parts Express, they make them in lots of sizes and do standard and heavy duty. A friend of mine put some of these on the passives on his Forte's, I'll see if I can confirm which ones he bought or another forum member may be able to find the old thread.

Parts Express Link for 15" Heavy Duty Grill

[SilverSport]

Colterphoto1 did that and bought the parts indeed from PartsExpress.com...

Bill

[Rivernuggets]

Has anyone put a protective grill on the passive radiator? (why?/why not?)

Depends on who's travelling through your listening/home theater room. With your Chorus IIs away from the wall and children around (friend's kids every so often) I'd consider protection. Here are some grilles from SpeakerWorks.com that have a tighter mesh style than Parts Express: http://www.speakerworks.com/15_inch_black_steel_speaker_grills_p/sgm15.htm

I've used 8" grilles of this style on a pair of KG 3.5s and they worked well. Once installed there are no visible screw heads around the woofer, and the grille can be easily removed (friction fit) for woofer viewing. Neat.

[vnzbd]

Thanks for the feed back. I do have children, 6 &10, and a dog in the future. Grills might be the option if I keep them. I have been comparing them with my KLF 20s and am a little surprised that them seem to image wider than the 20s. I am not used to hearing the instruments come from beyond the outer edge of the speakers. Nice! The base also surprises me. I expected more from the 15 and passive radiator. I have been as close as 6" to the wall and as far as 18". 18 seems closest to the sweet spot so far. The 20 bass wise do keep up and my 10s surpass them. I am running them in 2 ch with a Marantz 8500 rated at 125 per. Is my reciever to shy to push the woofers? Unfortanatly the 10s are shy on the mids.

To go a little of subject, How does the base from Cornwalls compare to the Chorus IIs?

[stormin]

I am running them in 2 ch with a Marantz 8500 rated at 125 per. Is my reciever to shy to push the woofers?

You need an amp to push those 15's. Those woofers have some low impedance dips and need some juice to do what 15's ought to do.

[stormin]

To go a little of subject, How does the base from Cornwalls compare to the Chorus IIs?

Chorus II's are tighter and hit harder but as I just said its going to take an amp that can do the job.

[vnzbd]

Stormin, Thanks for the insight. What type of amp do you currently use with your Chorus IIs? Other than wattage, what should one look for in upgrading to a amplifier vs receiver? Does your bass come alive at lower volumes with your amp or does the volume need to be pushed?

[stormin]

Stormin, Thanks for the insight. What type of amp do you currently use with your Chorus IIs? Other than wattage, what should one look for in upgrading to a amplifier vs receiver? Does your bass come alive at lower volumes with your amp or does the volume need to be pushed?

Thats the great thing about high powered high quality amps. The bass comes alive at lower volumes. One feature that I have always found to be a good indicator is if the amplifer power rating doubles as the load impedance is halved.

Right now I have a Crown K2 hooked up that is 500wpc @ 8 ohms. There is little trouble moving the woofers. QSC and Aragon are couple of amps that I find also work extremely well.

[vnzbd]

Stormin, If I understand what you are saying, the impeadence dips at certain frequencies causing the amp to see a lower load(resitance). At the lower impeadence or ohms the amplifier generates a higher wattage output. Believing the Woofer will eat up most of the power, the increased wattage provides more bass energy?

[stormin]

Stormin, If I understand what you are saying, the impeadence dips at certain frequencies causing the amp to see a lower load(resitance). At the lower impeadence or ohms the amplifier generates a higher wattage output. Believing the Woofer will eat up most of the power, the increased wattage provides more bass energy?

That is indeed the way I see it. I would also like to say that I am a huge rock/metal fan and that plays an important role as to the equipment I use. Also I am from the camp that the pre adds more to the sonic flavor than the amp. I feel its very important to have goals and build you system in the direction of those goals. There are other folks on this forum that also enjoy the Chorus II's but have different goals than myself. They enjoy all tube equipment and wouldn't have it any other way.

In the end its all about your own personal audio nirvana.

[vnzbd]

Stormin, Thanks for all the info. Have you done anything to yours like crossover upgrades and are you 2 channel only?

Can others can weigh in on what amplification they use with Chorus IIs and How many use them for 2 channel and/or home theater please?

[Marvel]

I would easily take a pair fo Chorus IIs over Cornwalls. I think they sound better and have more WAF. I had a pair here for a while that were in transit to another forum member. Only hooked them up once, but they were impressive speakers. I think they easily bested the Cornwalls I heard in Indy.

Bruce

[Montigue231]

I agree with you marvel. You would really have to step up to something huge to beat the Chorus II's. They can satisfy almost any audiophile with there sheer power and detail.

[DrWho]

Stormin, Thanks for the insight. What type of
amp do you currently use with your Chorus IIs? Other than wattage, what
should one look for in upgrading to a amplifier vs receiver? Does your
bass come alive at lower volumes with your amp or does the volume need
to be pushed?

I only have one pair of Chorus II's, but
my measurements indicate that the woofer is voiced a bit shy relative
to the MF/HF. Passive Radiators also seem to be a bit nonlinear at
lower SPL's and come to life when you push the volume a bit. You'll
actually see the bottom end come up quite a bit in the measurements as
you increase the SPL. It's very possible that the Chorus II was voiced
for louder SPL's.

The wattage of the amplifier isn't as
important so much as its output impedance...although generally
speaking, higher output power usually means lower output impedance. The
lower the better.

When the output impedance rises, the frequency
response of the amplifier starts to look like the impedance response of
the speaker. I lost the previous measurements I took, but I remember
there being a big impedance spike right in the middle of the midrange
somewhere...I wanna say 4kHz? Coupled with the slightly shy bass
response, any extra output in the midrange is gonna make it sound even
more bass shy. Any output impedance over half an ohm or so is where my
college buddies could notice a difference.

In college, I just
replaced the electrolytics with some film caps and changed the value a
bit to push the lowpass on the MF unit down a bit to attenuate some of
that bump in the midrange...which is gonna rule out most (not all) tube
amps.

The biggest gains I achieved, however, was moving to an
active xover so that I could goose up the woofer another dB or two and
EQ out some of the midrange humps.

Nevertheless, in stock form I
still prefer the Chorus II to the Cornwall. Although it can definitely
be said that the Cornwall will appear to have more bass in a side by
side comparison...but that's because there's a big bump in the low
frequency response (somewhere around 50-70Hz? I forget). The tractrix
squawker of the Chorus II is what seals the deal though...way more open
sounding mids than the exponential squawker in the Cornwall.

Right
now I've got some bad compression drivers on my MF/HF due to some DC
leakage from some amps I was building in college. I've been meaning to
get things fixed, but I think I'm gonna convert my Chorus II's to a
2-way design instead. I've been borrowing some 18 Sound horns and BMS
coax drivers, and it sounds better than the stock setup. Going 2-way
also makes doing an active xover a lot cheaper.

All that to say,
changing your amp might make a bit of a difference to the bass
response, but there are other ways to affect the voicing of the speaker
to a much larger extent. Of course they're more complicated and
probably more expensive too. I've been meaning to design a modified
xover to pad down the MF/HF, but that's kinda hard to do with damaged
drivers...so I haven't gotten around to it.

[stormin]

In college, I just replaced the electrolytics with some film caps and changed the value a bit to push the lowpass on the MF unit down a bit to attenuate some of that bump in the midrange...which is gonna rule out most (not all) tube amps.

The biggest gains I achieved, however, was moving to an active xover so that I could goose up the woofer another dB or two and EQ out some of the midrange humps.

Hey Doc glad you stepped in here.

Do you have some part numbers and instructions on your cap and value change?

Also in regards to the active crossover, did you build one for the chorus II's? If so, would you be interested in building another? Or maybe would an EV Dx38 be the ticket? Or how about a Berhinger DCX 2496 http://www.parts-express.com/pe/showdetl.cfm?Partnumber=248-669 . Would either of these work in a 3-way configuration?

Heck if I can make these Chorus II's even better I'm all for it.

Thanks.

[stormin]

The wattage of the amplifier isn't as important so much as its output impedance...although generally speaking, higher output power usually means lower output impedance. The lower the better.

"The output impedance of each channel shall be less than 10 milliohms in series with less than 2 microhenries in stereo mode" Crown K2. Maybe thats why the K2 works so well with the Chorus II's.