Technical Info for Monitor 70 Series II?

DavidNC

I REALLY enjoy my Polk Audio Monitor 70 Series II speakers. They're used in a two-channel stereo system, to play almost nothing but all kinds of classical music and opera. I'm using a subwoofer, but it is set to contribute very little reinforcement to the bass, which is already very satisfactory.

Three questions:

1. Can you give me the anechoic frequency response curve for these speakers?

2. How closely matched are the speakers to that curve, and hence to each other? (Mine aren't consecutive serial numbers, though they were both bought new, at the same time, from the same dealer.)

3. What is the tolerance range for the two 5W resistors in the crossovers?

I'm just trying to learn about speaker design, and how the anechoic response curve might help account for what I hear. I realize the in-room response is dependent on room factors. I am very pleased with what I hear in my room, which is quite large and well-damped.

Thanks in advance for your replies.

Outfitter03

The answer to #2 is 5%. Can't help you with # 1, 3. What are the other components in your two channel system?

Welcome to Club Polk DavidNC.

F1nut

1. Polk doesn't give out that info.
2. Your speakers are matched despite the serial numbers.
3. 10% +/-

tonyb

Imho.....your room,speaker placement, and where your sitting has more to do with what your hearing than any of the info you seek.

Tankman

DavidNC..Them M70's are some of the better Tower Speaker for the money.I had two of them with a PSW10 sub to fill in the lowend just a little.I still like what the M70's do for music.Are You using a amp with them?Get too know F1nut and Tonyb,these guys are a Wealth of Knowledge!Also Many of the OldTimers in here are great with help and tips on audio/video gear.

cnh

Welcome to Club Polk!

You have some interesting questions. But technical info almost never tells us as much as actually "hearing" the speaker. I'm sure there are dozens of speakers whose curves match the M-70s perfectly and sound "nothing" like them. Does Polk have such info? Probably. Is that the only thing they used to design those towers? Probably not!

Think about it like this. You can have a team of SpaceX engineers testing and modelling 24/7, but until that craft actually reaches earth orbit and gets back. Reality has not participated in all those calculations!

I wouldn't worry about the curves if what you experience is "good"!

Enjoy!

cnh

DavidNC

Thanks to all of you for replying.

I suspected Polk doesn't reveal their anechoic response curves, though they surely must have them. And I can understand that. It avoids gamesmanship in comparing speakers by comparing their published curves. BTW, I don't have to have the curve to enjoy the speakers. I just wanted to see what I'm hearing, so to speak.

As to my electronics, the preamp is an Audio Research SP-9 MkII, and the power amp is a Denon POA-2800. Both are mint and operating at spec. (One channel of the Denon is -2 dB at 100 kHz. Breaks my heart. LOL!)

So are the resistors 5% or 10%? And what would be gained by replacing them with 1% resistors? (Assuming the resistors were matched to 1% and the caps were replaced with 1% caps, how much closer would that match the two speakers' curves? Some of the difference must also be due to variations between the drivers from one speaker to the other. Does anyone know how that all teases out?)

And yes, I know the room is a much bigger factor than the small differences between the two speakers. My room is really quite satisfactory, and I've used Quad 63s, EPI 100s and 200Bs, and others, all quite successfully. I like sound that is similar to what one hears in a good symphony or opera hall (Carnegie, etc.), with warm bass, very flat midrange (from about 200 Hz - 2kHz, then tilted down until there is little audible energy above ca. 10 kHz. So I don't want "revealing" or "detailed" or "exciting" speakers which have ruler-flat frequency response to 20 kHz or beyond. And I rarely play anything louder than 85 dB SPL for more than a few seconds, or what one hears mid-hall in a symphony or opera production.

My in-room response curve is very much like what I've just described. That's why I was wondering what the anechoic response curve for these speakers looks like. I could measure them myself, but don't want to go to the trouble! LOL And probably won't.

DavidNC

Does anyone know for sure whether those resistors are 5% or 1% tolerance? Which one? (I would have thought 10%, since nothing else is printed on the resistors.)

DavidNC

Tank, I was AMAZED at how good they were. A buddy bought a pair based on my experience, and another buddy eventually will. Funny how some people assume something has to cost a lot of money before it can be any good. I bought them after helping a friend get some M50s for a small apartment, and hearing how good those sounded.

DavidNC

To all of you, a little history:

In the early '80s (I think), I bought a pair of SDA-1As, my first pair of Polks. Wonderful speakers for my kind of music (and probably ANY kind, for that matter). They had replaced a pair of Acoustic Research AR-2aXs.

Since those first Polks, I've owned and used several (not a lot) others. But if I'd known then what I know now (famous words for all of us, right???), I'd probably have kept the 1As, not bothered with the rest, and just enjoyed the music.

Live and learn!

DavidNC

FYI, answer to the question about resistor tolerance:

Phone call to Polk Tech Support. Theyr'e 5% resistors (and the xover is second-order).

F1nut

My mistake, I just looked at a bag of old SDA parts and the resistors are 5%. The caps are +/-10%.

tonyb

DavidNC wrote: »

Since those first Polks, I've owned and used several (not a lot) others. But if I'd known then what I know now (famous words for all of us, right???), I'd probably have kept the 1As, not bothered with the rest, and just enjoyed the music.

Live and learn!

Well said David. Once your ears tell you your in heaven relax and enjoy the tunes. I know your concerned with seeing what your hearing, but does that change anything ? Crack open a cold one, roll some tubes, and turn the volume up a tad. Happy listening.

DavidNC

Tony, not really concerned, just trying to see what I'm hearing, as it were.

ken brydson

smithson654 reported