response curves

Mr. Bubbles

Are there any frequency response curve graphs available for the SDA models in stock form? If so who generated them (Polk?), were they done in an anechoic chamber or are they room response graphs and where can I locate them?

heiney9

oliverbubbles wrote: »

Are there any frequency response curve graphs available for the SDA models in stock form? If so who generated them (Polk?), were they done in an anechoic chamber or are they room response graphs and where can I locate them?

http://www.polksda.com/srsreview.shtml

http://www.polksda.com/sda1creview.shtml

It's in the text of the review. Likely all you will find.

Why?

H9

Joe08867

I believe they used a chamber for all of these.

Like H9 Said though: WHY????

Response curves only give you some of the information. I have see speakers with less than optimal curves sounder better than a lot of speakers with great curves.

Mr. Bubbles

http://www.polksda.com/srsreview.shtml

http://www.polksda.com/sda1creview.shtml

It's in the text of the review. Likely all you will find.

Why?

Like H9 Said though: WHY????

Response curves only give you some of the information. I have see speakers with less than optimal curves sounder better than a lot of speakers with great curves.

Thanks guys. Interesting reads H9 have went to that site many times but haven't read the reviews yet.

I was just wondering and thinking about why the different models sounded different especially on the low to low mid sections. I realize that some of you guys believe I think too much about things and should just take things as they are but that is not me.

I am not necessarily planning on using the information for anything other than my own curiosity but I wanted to try and compare the different models response curves between units that had similar changes to the crossovers to somewhat get an idea as to what crossover changes created what type of response changes. i realize the drivers are different but the drivers must be very similar since some were simply subbed for other models as stock was being used up and many used the same cabinets/ volumes even though they were different models. Also some of these models simply went from round wire voice coils to squared wire and the side/ edge wound coils. That being said I realize that the drivers also had some effect on the differences but apparently ( at least in several cases) they didn't make a significant difference to Polk.

I wanted to get an idea about the bass response changes as well as the Mid bass/ mid range differences between the Blade/ Blade as compared to the Pin/ Blade since the crossovers are completely different in this section between these. Most all models (within their own category) have a very similar crossover in the tweet section and seemingly used similar tweets. This shows that Polk didn't find it necessary to update the tweeter section drastically over time but they apparently did feel the need to update the mid/ bass sections drastically over time. This not only is evident in the crossover and drivers but the addition of the sub bass drivers in some models.

heiney9

When I asked "why" I wasn't being derogatory, just wondered why you wanted to know. The thing is as has been stated before it seems the SDA's were more of a "work-in-progress" than say the Monitor line so they were tweaking a lot on the fly as they a) discovered new things b) finally used up old parts.

There are lots of small variations to the same generation of SDA models, so some of differences in sound come from that fact. Some of the difference won't even be picked up on these types of tests because as you saw Stereo Review, while finding the 1C an improvement, commented it measured almost the same in all areas as the previous SDA 1 they tested.

The I/C connector came in (2) types with 3 uses. Blade/Blade both had a signal; PIN/BLADE both having a signal and PIN/BLADE pin having the signal and the blade for stability.

H9

heiney9

oliverbubbles wrote: »

This shows that Polk didn't find it necessary to update the tweeter section drastically over time but they apparently did feel the need to update the mid/ bass sections drastically over time. This not only is evident in the crossover and drivers but the addition of the sub bass drivers in some models.

Your answer is in the articles, especially the 1C review. Polk later found by limiting the SDA portion to a narrower frequency range they actually improved the process as well as simplified the x-over in the process.

Mr. Bubbles

When I asked "why" I wasn't being derogatory, just wondered why you wanted to know. The thing is as has been stated before it seems the SDA's were more of a "work-in-progress" than say the Monitor line so they were tweaking a lot on the fly as they a) discovered new things b) finally used up old parts.

I did not take it as being derogatory at all. I get the work in progress thing i just wanted to get an idea of why they settled on what they settled on since I naturally can't afford nor have room for all the different models and can't hear for myself the differences.

Your answer is in the articles, especially the 1C review. Polk later found by limiting the SDA portion to a narrower frequency range they actually improved the process as well as simplified the x-over in the process.

Not exactly, I am looking more at the differences between models like the 2A and 2B, or the SRS and the 1.2, etc. Same or very similar cabinet, very similar driver compliment but different sound, from what I think would primarily be due to the crossover changes. The interconnect appeared to change as the pins changed like the B/B carrying signal almost directly from the positive speaker terminal of each driver to the other to the P/B carrying signal from the negative leads of the dimensional drivers to the negative leads of the other channel dimensional drivers and strapping the negative speaker leads together from each channel (basically no function), to the same set up but without the negative leads strapped together on P/B as well. i am basically just wondering how the crossover changes effected the overall output and from there trying to gain some insight as to why the designers settled on the changes that they did for what ever benefit can be gained from them.

naturally with any change there is give and take. I am interested in understanding not only the benefits of the changes but what may have been the negative side as well. Also curious as to why they felt the desire to add the sub bass radiators to some models, and their effect on the response of the speaker design.

heiney9

What model doesn't use a sub bass radiator. You are just caught up in different terminology for the same part that does the same thing. The PR's are mostly interchangeable between the same models, of course some slight changes were made from say an original 1 to 1C.

The scope of your question is ambitious and I know most of the information is here on CP scattered over the past 10 years of posts. Too bad you weren't around when Darqueknight was selling his 2nd Edition SDA Compendium, it has lots of facts in it but the scope of your questions are deeper than what's covered and he and the compendium are the most comprehensive sources of information you'll find this side of Matt Polk and a handful of other engineers.

H9

Mr. Bubbles

What model doesn't use a sub bass radiator. You are just caught up in different terminology for the same part that does the same thing. The PR's are mostly interchangeable between the same models, of course some slight changes were made from say an original 1 to 1C.

I apologize, I typed radiator in my last response when i meant driver as I had originally typed. I am not speaking of the passives but actual sub bass drivers as in the 2.3's. Not the same thing.

I have a lot of experience and I like to think a good bit of knowledge from that experience in cabinet design and audio but very little in the realm of passive crossovers. I am trying to understand not just the passive crossover designs but also how the engineers implemented them for the SDA effect. I am gaining a good bit of ground just by studying the schematics posted in the sticky and can see the subtle as well as significant changes that were made from model to model but cant hear the effect of those changes. That is why I asked for the response curves; it is the closest I could get to hearing them without actually doing so.