SDA 1C vs SDA 2B

Mr. Bubbles

I recently purchased a pair of SDA 1C's have had a set of 2B's for a while and love the sound of the 2B's but wanted a little more uumph, so I picked up the 1C's. I had the issue with the passives as mentioned in my other post, but got it resolved to the point I feel comfortable using the speakers.

When i compare the 2 sets the 2B's seem to have a better bottom end. The 1C's sound very clear and not distorted at all except on the lowest of bass notes. They seem to be much more midrange heavy than the 2B's. This is the case on both my Adcom 555II as well as my Marantz 170dc.

Both pairs sound great but I expected more bottom end from the 1C's than the 2 B's but that is not what I am getting. has anyone else ever compared the 2, and is what I'm hearing normal or could I have a crossover problem or other issue casing this.

One point to note is that I am using the Polk SDA cable on the 1C's and a home made cable on the 2B's, but I don't see how this could cause any issues. i don't see anyway to cause an out of phase issue with the sda cable.

leroyjr1

You should be getting better bottom end with the 1C's. Something isn't right.

F1nut

For starters, remove that Dynamat from the one 1C. Next, try the push test to check for air leaks.

Consider upgrading the 2B's to TL's and add Larry's rings. The results are amazing. IMO, the 2BTL's will outperform a modded pair of 1C's.

dpowell

Mine became better on the bottom end after setting them on granite slabs. Spiking them is also a good way to improve the bass response. Play with configuration a bit. Spacing from walls can make a difference.

Mr. Bubbles

For starters, remove that Dynamat from the one 1C. Next, try the push test to check for air leaks.

It's definately not a dynamat issue; no way the damping effects of the dynamat could decrease output in any way that I know of. Also I have a/b'd the two 1C's and there is no difference that I can tell either stereo or mono, with or without the SDA cable, between the two. What ever it is, it's definitely in both cabinets. I have now switched the 2 "SDA" cables I have and that makes no difference, It sounds like a phasing issue but not between left and right. I am wondering if it may be a crossover issue since all midbass drivers are supposed to be fully complimentary below approximately 150hz. Maybe this is not happening. It does sound slightly better without the SDA cable connected in mono. With the cable connected it makes no difference. But let me be clear, this is only a very slight difference.

Consider upgrading the 2B's to TL's and add Larry's rings. The results are amazing. IMO, the 2BTL's will outperform a modded pair of 1C's.

At the risk of sounding ignorant on the matter; what makes a "TL". Where would I find info on performing that. Please explain this a little more and give more reasoning for this suggestion.

Mine became better on the bottom end after setting them on granite slabs. Spiking them is also a good way to improve the bass response. Play with configuration a bit. Spacing from walls can make a difference.

I am sure these things can and do make a difference. I have not tried spikes on either one and my rooms are carpeted. I have tried the spacing from the wall on the 2B's for great results. However i am comparing these 2 models in the same locations. With a location set as standard for comparison, the 2B's are stronger and cleaner on the bottom end. This is simply a comparison with all other aspects remaining constant.

F1nut

http://www.polkaudio.com/forums/search.php?searchid=17770314

Mr. Bubbles

Let me make another note here. The 2B's have been used in this test until now with a loose passive in the right cabinet, and still have better bottom end (in trying to figure out my passive radiator issue I removed these and somehow missed tightening one of them back down).

The other difference I can see is the driver placement in the cabinets. The passive as well as the drivers are closer to the floor on the 1C's than the 2B's. This should theoretically provide for a slightly increased bass output.

Tony M

Make sure your terminal screw nuts are on correctly. That would kill bass for sure if one set is backwards, I know. Or your wires are crossed on one leg. That has happened to me personnally by my own hands.:redface:

I had an issue with CRS's and the previous owners had switched the nuts somewhere along their long life.

Mr. Bubbles

Tony that is something I haven't exactly checked yet. I have listened to each speaker individually with and without the SDA cable and also switched to mono as well as in stereo mode so I don't think the cabinets are out of phase with each other. Maybe I should describe better; it's not that the bass is dead. There is bass there and it is mostly clear. It's just that it is weaker in both clarity and impact than the bass from the 2B's, and the 1C's have twice as many drivers.

geppy1

When I compared 2Bs to 1Cs for weeks (both Dynamated and Mortite treated) I felt the 2Bs were quicker, had more punch and slam but had a thinner midrange. The 1Cs midrange was more full but added a slight heaviness to voices and the bass was not as quick or as tight as the 2B I also tried 2As and got the same impression. I felt the 2Bs and 2As were a little better for rock. The 1C is rated 35-20,000+/-3 and the 2B is 38-20,000+/-3 so not much difference there



Sometimes when people say a speaker has a better bottom end its hard to know what they means. As an example in comparing LS 90s to RTA 12Bs if a person who was not real experienced walked into the room they would think the 90s have better bass because it is heavier the balance seems tilted that way. Boom Boom In reality the RTA 12 is more accurate, goes lower and has been verified 20-20,000 +/- 4db . The LS 90 is 35-20,000

Does bass go deep, or have more punch, or have more weight, slower, faster??

I think everybodys idea of what good bass is can vary a lot

Mr. Bubbles

I think everybodys idea of what good bass is can vary a lot

You are exactly right on this. I thought I had given a decent description of what i am hearing but just as everybody's idea of good bass can vary, so can their ways of describing it.

The depth of the bass sounds very much the same but on the 1C's it seems sloppier and not nearly as controlled as the 2B's, especially down low. The 2B's are also slightly more prominent in the bass notes (even on the low notes). The 2B's just seem to have more of almost everything in the bass region; more volume, more clarity, more depth (though I think this is more of an impression due to the stronger output down low and not really a deeper extension.), more control. The 1C's definitely have a much stronger mid-range, this naturally brings the vocals out significantly.

Mr. Bubbles

What i am hearing may very well be normal for these but just not what I expected.

Though the tuning of the passives has a lot to do with the bass response, there is not huge difference in cabinet volume between these 2 models and the 1C has twice as many drivers. I would expect the bass in the 1C to be tighter due to the smaller per driver enclosure. Given the tuning of the passive for roughly the same extension i would expect the response curves to vary somewhat between these 2 models but again would expect the 2B's to be sloppier due to the higher per driver volume of the cabinets.

I assume these 2 models use different drivers which could very well have something to do with this since the driver specifics would naturally be different. (this is just my assumption and I don't truly know which drivers either model uses). The crossovers would also be different causing some of this effect.

I wonder if anyone around here has ever run response curves on these 2 models or is that something that can be found through Polk. Also is there anyone that would know more specifics of the crossover design and filter frequencies, slopes, etc. I am sure the driver specs are proprietary to Polk but maybe someone else has tested these so as to have the specs available.

Tony M

10/4

Are both of the red terminal nuts on the left side on the 1C's ?

heiney9

My 1C's have deep articulated bass, not sloppy and very extended as in I can feel it through my toes and into my butt. I'd say you have an issue with placement or x-over/driver/passive radiator related.

2B's are no slouch but side by side the 1C's should be better in all aspects of bass, all things being equal.

H9

Mr. Bubbles

tony millard wrote: »

10/4

Are both of the red terminal nuts on the left side on the 1C's ?

Yes

2B's are no slouch but side by side the 1C's should be better in all aspects of bass, all things being equal.

This is my expectations and the basis of my concerns.

heiney9

You could have a weak capacitor in the low pass causing the bass to be diminished. The caps are going on 20+ years old. I would start there after confirming you don't have any serious cabinet leaks, etc.

H9

Conradicles

I'll chime in and give my humble opinion. I have had 2 sets of 2B's and 1 set of 1C's.

1st of all I would open up the SDA-1C's and make sure they are wired correctly. The fact that Polk used the black wires as positive instead of negative can lead to mistakes over the years of the speakers life. My 1C's were wired incorrectly which killed the bass.

Both are great speakers:
- The 1C's have better midrange to me.
- Stock 2B's sound too thin in the midrange. Many claim they get much better with the TL upgrade.
- Bass on the 1C's, while not as heavy as the 2B's, sounds more accurate to me.
- The 2B's are more cost effective to upgrade.

Again, I love them both. Really you can't go wrong with either one. Pick the one that sounds best to you. Enjoy.

geppy1

I guess it is personal taste and perception. Three or four of us who sat and listened all worked in the CE biz ana one guy set up bands back in the day and we all reached the same conclusion. The 1Cs were not as tight as the 2Bs. A Rotel RB 990BX 200 watts per channel into 8 ohms was used (which has as high a damping factor as anything out there) as well as two or three other units. The 1Cs are more filled in in the midrange and it may?? be more accurate in the bass . The stage seems a little more forward with the 2Bs

Mr. Bubbles

starting to sound like what I am hearing may very well be normal. Not surprising, My ears tend to be a fan of relatively smaller and simpler systems. I am still curious, however, why the 1C's with twice as many drivers seem to have an overall lower bass output (detail, tightness,etc not being considered). Maybe it's the drivers or the crossover, or both.

Conradicles

oliverbubbles wrote: »

starting to sound like what I am hearing may very well be normal. Not surprising, My ears tend to be a fan of relatively smaller and simpler systems. I am still curious, however, why the 1C's with twice as many drivers seem to have an overall lower bass output (detail, tightness,etc not being considered). Maybe it's the drivers or the crossover, or both.

Also note it could be the power you are feeding them with. Usually with more power the bass response will increase. Maybe the 2B's are getting what they need, and the 1C's with the extra drivers and tweeters are not. Just a thought.

Mr. Bubbles

Have tried them on both my Adcom 555II as well as my Marantz 170DC either of which should be plenty of power, I would think. I do have a larger Sansui but it is kind of a pain to get to right now. not sure the model # on that one. Also haven;'t tried them on the smaller marantz and Adcoms I have as i didn't think going smaller would have any better effect.

From the comments I have gotten here there are definitely more that seem to have similar descriptions as to what I am hearing, so i think this may be normal for these 2 models, just not what I would expect. I am going to continue digging and researching to see if anything else pops up.

I notice that the 2B's use the same drivers for their dimensional drivers as the 1Cs use for the stereo drivers and the dimensional drivers in the 1Cs are a different # than either used in the 2B's and likewise for the 2B's stereo drivers. I am sure there are differences in these drivers which naturally would equate to somewhat different sonic characteristics. The differences in these drivers also would require differences in the crossovers components which also would naturally equate to somewhat different sonic characteristics.

I am now thinking that this difference is somewhat normal but am still not understanding why this would have been designed that way given public perception and expectation.

geppy1

Look at it this way. The perfect speaker would be a one driver unit but that is very very hard to do. The more drivers the harder they are to control and the more high current power and the higher the damping factor you need. My take over the last 35 years playing with audio stuff is the fewer drivers the tighter and more controled the bass. Not just Polk but almost anyones speakers . There are exceptions and combinations that work well.
The 2Bs have more punch and kick, that does not mean it is right. The 1Cs may be more accurate but it depends on what you like and your taste more then anything. I think (and others have mentioned it) the 2Bs, 2As are better for rock because of the more forward sound and kick or punch on the bottom. The 1Cs (to me) are a little softer and maybe better for other types or music. Any way you cut it none of this means anything at all and at the end of the day it comes down to this.

Given your system, your room, the music you listen to, your personal tastes which one do you like better? Does not matter if it is accurate or not accurate, loose ,tight, bright not bright ect ect. Which do you like better??

heiney9

oliverbubbles wrote: »

Have tried them on both my Adcom 555II as well as my Marantz 170DC either of which should be plenty of power, I would think. I do have a larger Sansui but it is kind of a pain to get to right now. not sure the model # on that one. Also haven;'t tried them on the smaller marantz and Adcoms I have as i didn't think going smaller would have any better effect.

From the comments I have gotten here there are definitely more that seem to have similar descriptions as to what I am hearing, so i think this may be normal for these 2 models, just not what I would expect. I am going to continue digging and researching to see if anything else pops up.

I notice that the 2B's use the same drivers for their dimensional drivers as the 1Cs use for the stereo drivers and the dimensional drivers in the 1Cs are a different # than either used in the 2B's and likewise for the 2B's stereo drivers. I am sure there are differences in these drivers which naturally would equate to somewhat different sonic characteristics. The differences in these drivers also would require differences in the crossovers components which also would naturally equate to somewhat different sonic characteristics.

I am now thinking that this difference is somewhat normal but am still not understanding why this would have been designed that way given public perception and expectation.

As a point of reference have you read the original Stereo Review, review of the 1C's.

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

They don't seem to have an issue with bass at all, in fact they are quite complimentary about it. I realize reviews should be taken with a grain of salt, but perhaps just as another point of reference, it could help.

There is no way 2B's should have more bass than 1C's. There are more drivers contributing, as well as the cabinet being larger. Now, if the issue is which sound you prefer that certainly could be a personal choice, but if there is less bass coming from the 1C's, then there is an issue.

I used to sell both model's side by side and the 1C's always performed better in all area's. Not by a huge margin, but they did everything a little better. I'd keep investigating because something just doesn't seem right.

Good luck

H9

audiocr381ve

Spike those sons of mothers!