Documenting: My SDA-1c upgrades from start to finish

F1nut

Polk used sub-par caps and crap cast resistors to cut costs.

Nope. They used what was available and in the quantity required at the time.

That's straight from Matt Polk and he would know.

invalid

Gardenstater wrote: »

Efficiency at higher power levels is actually improved, by cooling the voice coil and reducing power compression.

The small loss of cone area is probably more than offset by not having to compress the enclosed air space underneath the dust cap which can also be a source of resonance and coloration.

I haven't noticed any dB drop on the freq. response curves I have made and compared to pre phase plug.

Anything attached to the cone is just a pointy shaped dust cap and would lose most of the benefits of a phase plug attached to the pole piece.

Are your phase plugs attached directly to the pole piece or just the cone? The efficiency goes down a little when it's attached to the pole piece do to a small air leak. If it's just attached to the cone it's more of an ornament than anything else.

plastic_avatar

- The plugs are attached to the pole piece.

- I think everyone cuts corners unless money is no object. One of the things I think is great about Polk speakers is they are so readily improved by doing mods that could've been standard, but weren't. That they make such great speakers whilst cutting corners is admirable. I respect the effort and am thankful for the chance to improve.

Gardenstater

invalid wrote: »

Gardenstater wrote: »

Efficiency at higher power levels is actually improved, by cooling the voice coil and reducing power compression.

The small loss of cone area is probably more than offset by not having to compress the enclosed air space underneath the dust cap which can also be a source of resonance and coloration.

I haven't noticed any dB drop on the freq. response curves I have made and compared to pre phase plug.

Anything attached to the cone is just a pointy shaped dust cap and would lose most of the benefits of a phase plug attached to the pole piece.

Are your phase plugs attached directly to the pole piece or just the cone? The efficiency goes down a little when it's attached to the pole piece do to a small air leak. If it's just attached to the cone it's more of an ornament than anything else.

I don't think efficiency is the term you are looking for, which is dB SPL at 1W and 1m.

Some of the early dust caps were made of felt but the later ones were more gauzelike and you can shine a flashlight through them. Lots of air porosity. Even with my felt like dust cap that I had, I have not lost any time on the leakdown test. Mine take forever to fully return to home position. So long that I have never had the patience to time that. Think about the extra length of narrow annular space presented by the phase plug inside the voice coil former.

xschop

F1nut wrote: »

Polk used sub-par caps and crap cast resistors to cut costs.

Nope. They used what was available and in the quantity required at the time.

That's straight from Matt Polk and he would know.

So only crap was available?

F1nut

xschop wrote: »

F1nut wrote: »

Polk used sub-par caps and crap cast resistors to cut costs.

Nope. They used what was available and in the quantity required at the time.

That's straight from Matt Polk and he would know.

So only crap was available?

Your reading comprehension needs improvement.

Besides Rob, even today there are very expensive speakers using like/kind components. It's rare to find high quality caps and resistors in production speakers.

plastic_avatar

@skipshot12 Here is a better diagram and explanation of what my daughter and I heard:

The room is the thing

- 6ft between the speakers
- speakers are 3'ish feet from the side walls
- room is 14+ ft wide
- this section of the room is 12+ feet long
- the center of each speaker is 10ft from the listener's head
- the distance between the wall next to the side chairs and the outer edge of each speaker is 4.5 feet

This image shows where and when instruments appeared.

1. bass ahead of the speaker plane

2. drums behind bass, with high hat appearing to the right of the bass when struck. sounds very natural, like that sharp sound penetrates forward at an angle from seated drummer

3. guitar #1 almost sounds like he's sitting in the wall, angled towards listener, the guitar about 3 ft on the diagonal from the outside edge of the left speaker. way ahead of the speaker plane

4. keyboards? I thought it was a filtered guitar at first... jazzy funky sounds throw me. similar location as 3 across the room, but more isolated (might be the difference between wall treatments). angle slightly turned towards back of listener's position, and a hair more forward from speaker plane than 3

5. guitar 2? off left corner of left speaker

6. horns. within left speaker and high on the height measurement... at the top of the speaker. 6 on the right sounds like a synth mirroring the horns' notes. subdued, but there

7. solo horn/wind instrument. sounds like it's right next to the high hat, but a little forward, kind of like it wraps around it to get to my ear

This was the soundstage to the 3 minute mark.

Definitely biased to the left due to room differences, for presence of sounds. Right of high hat cymbal noises were more subdued.

The new #2

And that's all the speaker performance information I've got to give tonight.

I'm super pleased by the SDA effect.

I believe the bass on the left is more taut. Could be room, could be coating on the passive chamber, could be both.

Bass isn't as strong in force as the M12, imo, but the quality of it is better. Might be the benefit of SDA clarity?

invalid

I don't think efficiency is the term you are looking for, which is dB SPL at 1W and 1m.


Actually that is sensitivity not efficiency.

xschop

F1nut wrote: »

xschop wrote: »

F1nut wrote: »

Polk used sub-par caps and crap cast resistors to cut costs.

Nope. They used what was available and in the quantity required at the time.

That's straight from Matt Polk and he would know.

So only crap was available?

Your reading comprehension needs improvement.

Besides Rob, even today there are very expensive speakers using like/kind components. It's rare to find high quality caps and resistors in production speakers.

Perhaps the author's conveyance of subject matter is incomprehensible.

xschop

invalid wrote: »

Gardenstater wrote: »

Efficiency at higher power levels is actually improved, by cooling the voice coil and reducing power compression.

The small loss of cone area is probably more than offset by not having to compress the enclosed air space underneath the dust cap which can also be a source of resonance and coloration.

I haven't noticed any dB drop on the freq. response curves I have made and compared to pre phase plug.

Anything attached to the cone is just a pointy shaped dust cap and would lose most of the benefits of a phase plug attached to the pole piece.

Are your phase plugs attached directly to the pole piece or just the cone? The efficiency goes down a little when it's attached to the pole piece do to a small air leak. If it's just attached to the cone it's more of an ornament than anything else.

For me I would prefer that the cone speed increased no matter what. I believe that the alloy plugs do this 2-fold by eliminating the chamber, and it's aerodynamic shape.

More cone speed translates to better transients.This is especially beneficial due to the fact these drivers are tasked with low and mid frequency reproduction.

skipshot12

plastic_avatar wrote: »

@skipshot12 Here is a better diagram and explanation of what my daughter and I heard:

The room is the thing

- 6ft between the speakers
- speakers are 3'ish feet from the side walls
- room is 14+ ft wide
- this section of the room is 12+ feet long
- the center of each speaker is 10ft from the listener's head
- the distance between the wall next to the side chairs and the outer edge of each speaker is 4.5 feet

This image shows where and when instruments appeared.

1. bass ahead of the speaker plane

2. drums behind bass, with high hat appearing to the right of the bass when struck. sounds very natural, like that sharp sound penetrates forward at an angle from seated drummer

3. guitar #1 almost sounds like he's sitting in the wall, angled towards listener, the guitar about 3 ft on the diagonal from the outside edge of the left speaker. way ahead of the speaker plane

4. keyboards? I thought it was a filtered guitar at first... jazzy funky sounds throw me. similar location as 3 across the room, but more isolated (might be the difference between wall treatments). angle slightly turned towards back of listener's position, and a hair more forward from speaker plane than 3

5. guitar 2? off left corner of left speaker

6. horns. within left speaker and high on the height measurement... at the top of the speaker. 6 on the right sounds like a synth mirroring the horns' notes. subdued, but there

7. solo horn/wind instrument. sounds like it's right next to the high hat, but a little forward, kind of like it wraps around it to get to my ear

This was the soundstage to the 3 minute mark.

Definitely biased to the left due to room differences, for presence of sounds. Right of high hat cymbal noises were more subdued.

The new #2

And that's all the speaker performance information I've got to give tonight.

I'm super pleased by the SDA effect.

I believe the bass on the left is more taut. Could be room, could be coating on the passive chamber, could be both.

Bass isn't as strong in force as the M12, imo, but the quality of it is better. Might be the benefit of SDA clarity?

Thank you for splaining.... way cool.

plastic_avatar

Follow-up to baseline

I went back at lunch and read over DK's description of where sounds came from in what I consider *the* baseline for whether or not my SDA effect works (and whether it works as intended).

This is what I care about for this part of the evaluation; does my 1C SDA effect mimic an established baseline?

DK's write-up

"Here is what Herbie Hancock's "Chameleon" (from his "Headhunters" CD) sound like on my hotrodded SDA SRS 1.2TLs.

The song begins with electric bass which is in the center of the speaker plane.

Drums come in at 00:13 three feet behind the electric bass. This sound image comes from behind the rear wall.

Electric guitar starts at 00:35 and is three feet to the left of the left speaker and four feet in front of it.

Electric piano starts at 00:54 and is three feet to the right of the right speaker and four feet in front of it.

Synthesizer starts at 01:12 in the speaker plane 1 foot to left of left speaker and 1 foot above the electric guitar image.

Horns start at 01:30 and are at the top of the left speaker directly above the synthesizer, as if the horn players are standing on a platform behind the synthesizer player.

The sound stage on this recording, on my speakers, is crescent shaped and 16 feet wide, 7 feet deep, and 5 feet 4 inches high. The sound images are life size with lifelike sonic "weight" and a sense of space
between instruments. I can turn my head left or right to "look" at a particular sound image and the other
images will remain firmly in their places, just like real performers on a real stage."

How does my experience compare?

Not too shabbily!

- Where DK has a crescent that begins 3 feet behind the bass and beyond the wall, I think mine begins at the wall. The bass is forward of the speaker plane for me, and the drums are behind the bass and up to the wall, with the high hat kind of wrapping around the bass to the be more forward of the drum sounds and to the right of center.

- The electric guitar and piano sounds are similarly placed. We heard those sounds slightly beyond the side walls and about 3 feet on the diagonal from the speaker plane.

- The synth (I called it guitar 2) is placed appropriately, but we didn't hear it much higher than guitar 1. DK had additional spatial deliciousness on the vertical.

- The horns were solidly in the confines of the left speaker, not that it sounded like it was beaming from the box, but they were audible from that space, and just peeking above the top. Not nearly as high up as DK's. The top of our sound field was about 3 ft 8 inches

What's next?

I'd love to have some baselines from a few of you with lightly-modded 1C for figuring out if the quality of sound on my Frankenmods is up to standards.

If there was an agreed-upon song we all had access to on CD, for instance (since I'm not in the DAC world for HQ streaming, yet). Yeah, I know there will be differences between players and amps and all that.

Please, if you can think of a methodology for this part of the process... let's have it!

- I believe my crescent was possibly 2 feet narrower, and the crescent depth (from the ends of the crescent to the terminal image at the rear of the sound field) was probably 2 feet shallower.

heiney9

You also have to remember DK's gear is far, far better than what you're using. That alone will make a HUGE difference. His room has been treated as well. Not really an apples to apples comparison, but at least you have a high bar to shoot for.

I am just trying to speak the truth, not ragging on your gear. We all are invested differently in this hobby for all kinds of reasons.

Keep having fun, that's really all that matters.

H9

mhardy6647

invalid wrote: »

Cone Speakers designed properly with phase plugs attach the phase plugs to the pole piece and not the cone, Some efficiency is lost with this design. Some speakers have the phase plugs attached to the cone, which has little if any effect.

Now that you mention it -- I've actually thought about that. Given that the whole plug is moving, the wave mechanics of what's going on with the cone and the plug would be really complicated, methinks. If nothing else, I'd be sure that the plug's effect, if any, will be qualitatively and quantitatively far different than the traditional stationary phase plug.

Some of the classic Lowther phase plugs bring Mr. Magoo to mind...

plastic_avatar

heiney9 wrote: »

Not really an apples to apples comparison, but at least you have a high bar to shoot for.

I am just trying to speak the truth, not ragging on your gear.

Keep having fun, that's really all that matters.

Apples = Just an SDA to SDA placement comparison. Like, Honeycrisp to crab apples. All the parts are there, but the crab apple is smaller and doesn't taste the same (but might be just as sweet).

That old rag = I gotcha. I just cared if the 1C were able to approximate the Olympian baseline. I was honestly surprised how well the SDA effect works between (at the very least) our 2 experiences. That speaks volumes for the tech. And that the placement of elements is consistent across at least 2 models in very different rooms blows my mind. But that's just placement and the shape of the soundfield I'm comparing! I'd like to get some 1C baselines up and going so I can see how the soundfields and quality of sound compare. (I wasn't even going to suggest a quality of sound comparison between DK's and mine.)

Fun = In spite of everything, yes My 2nd most fulfilling and worthwhile project of the past year.

xschop

Just finished reading again. This is the best documentation of soundstage and SDA imagery Ive seen here. Kudos.

plastic_avatar

Before I get into evaluating how a bona fide pre in my system sounds next week (to replace my receiver-as-pre), I wanted to put something to rest.

I did it my way...

...for reasons.

I tell you here, so let's not dwell on it anymore.

Fair?

https://youtu.be/kMPkgi-G1ro

DarqueKnight

When I did my first SDA mod, in 1990, to a pair of SDA 1Bs, I did all the mods I knew about at once:

1. Better caps.
2. Better resistors.
3. Foam tape on the baskets.
4. Removal of the polyswitch.

It never occurred to me to do them one at a time in order to gauge the incremental improvements. I doubt I would have done them one at a time even if Polk had advised it. My interest in modding my speakers (not jut my Polks) grew out of my interest in modding my Sony, Denon, and Yamaha CD players:

1. Better output caps.
2. Better clocks.
3. Case damping.

It took a very long time for me to grow into the uber tweak that I am now. It's not that I didn't appreciate high end, high performance audio from the very beginning. I just had other priorities until around 2003. That's when I became seriously interested in cables, power cords, isolation tweaks, high performance separate amplification components, and serious performance evaluation of stereo gear.

I have been a member of this forum since 2001. My journey and growth in this hobby has been well documented here.

plastic_avatar

DarqueKnight wrote: »

When I did my first SDA mod, in 1990, to a pair of SDA 1Bs, I did all the mods I knew about at once…

I’m glad you understand that there’s no disrespect to anyone’s input in why I didn’t take it one mod at a time.

It took a very long time for me to grow into the uber tweak that I am now.

That’s nice to know. I got here 8 years after you, but didn’t get in the swing of learning more until 3 years ago. I learn something everyday. I love learning.

Because it’s an easier build, I can mod my 5B one-step-at-a-time this year. I’m looking forward to that. I’ll be able to appreciate the changes, and hopefully contribute some solid data on those changes- positive or negative

BlueBirdMusic

^^^^ I learn something everyday. I love learning.


IMPORTANT!!

skipshot12

Thanks p_a....

Was thinking I was gonna hear your work with a listen of your speakers.
This was a good listen anywho 👍
Carry on Big Daddy.

Skip

DarqueKnight

plastic_avatar wrote: »

I’m glad you understand that there’s no disrespect to anyone’s input in why I didn’t take it one mod at a time.

I have been following this thread since its beginning. I don't recall that anyone accused you of being "disrespectful" by doing a lot of mods at once. Others, including me, have done several mods at once and I don't recall any accusations of "disrespect" in any of those situations.

My take is that the main concern others have is with the phase plugs. I think it comes from a place of genuine concern that you might mess up your speakers. This is a modification that alters the fundamental design of the drivers. It is also a modification that has the potential for lowering the performance of the speakers. This is particularly true since SDAs are not conventional speakers. On the surface, the phase plug mod appears to have destructive potential, and, unlike the "mainstream modifications" done for years on the forum, it is not reversible on the drivers themselves. If someone doesn't like it, they would have to replace pairs of rare drivers. I had these concerns, yet I was intrigued enough to try it.

You seem to be happy with the results and that is all that really matters. As you have noted you really won't be able to assess the quality of the phase plug modification until you compare them to a similarly modified pair of 1Cs without phase plugs. One thing you could try is acquiring or borrowing stock drivers and re-running your listening evaluations. I appreciated your detailed listening evaluations along with sound stage maps.

In my case, I added the phase plug modification to a highly modified pair of SDA CRS+s that I have owned for a long time. The results were not positive. Overall clarity, detail, and imaging performance were lowered. I had the benefit of years of listening experience prior to the phase plugs. I did before and after listening trials with the phase plugs which included my standard practice of mapping the location and quality of sound images.

plastic_avatar

DarqueKnight wrote: »

plastic_avatar wrote: »

I’m glad you understand that there’s no disrespect to anyone’s input in why I didn’t take it one mod at a time.

My take is that the main concern others have is with the phase plugs. I think it comes from a place of genuine concern that you might mess up your speakers.

I appreciate that concern. Honestly.

There is a way I could've waited on those, as opposed to the other mods, and done them 1 drive after another with weaker glue to test. At the time, I didn't think of doing them in place and mounted. Didn't cross my mind as an option on the mod chain. I don't think anyone else suggested that, either. Just 'whoosh'! Missed it. That option went right over my head.

And even though it would've meant extra agony, I built in the possibility that I might need to reverse the mod. Not easy, but doable (and my magnet jig is almost ready now).

You seem to be happy with the results and that is all that really matters.

And impossible to do without the help from this forum.

But finding out how they compare to stock is also important, to me. I just have to wait for that opportunity. But the good news is I'll have a lot of time with these to be familiar with the differences- positive and/or negative.

One thing you could try is acquiring or borrowing stock drivers and re-running your listening evaluations.

Side goal is to find another pair and do comparisons with the same crossovers from mine. Finding another $150 pair will be tough...

I appreciated your detailed listening evaluations along with sound stage maps.

Thank you. One day I'll have posts more like yours, but right now I'm still using fat crayons.

In my case, I added the phase plug modification to a highly modified pair of SDA CRS+s that I have owned for a long time. The results were not positive. Overall clarity, detail, and imaging performance were lowered.

I hope I end up being a usable data point in the future. After I'm able to compare. I'm insanely curious about it. And I do wonder what part arrangement might play on which drivers are plugged, the shape if the plug, the treatment on the baffle, and with what material.

skipshot12

Would really be nice if I could do this…..
Once done with the mods of my gen 3 sda SRS’s it would be neat as hell to have a set of completely originals to compare with.

Rather than relying on memory I could do an a-b comparison.
I’d wager that even a novice music listener would be astonished at the difference in the two?

plastic_avatar

Additional burn-in was delayed

I don't think I hit 160 yet. Not much listening this week. Character of sound still changing. Crazy. I'll probably start leaving them on overnight if I feel it's safe. Maybe next week.

PRE!!!

So excited it's killing me. Member Daveho set me up with a beautiful, minty fresh Parasound P/HP-850. And the guy packs like God's personal gift wrapper. Packed to perfection.




Next purchase steps have changed. Got to upgrade stereo a little more before I consider inductors/coils. After I pay off the emergency vet bill from last night... likely a combo of a Wiim Mini to stream sources like Amazon/Tidal/etc. natively, then get a real entry-level dac via a standalone dac (like a Geshelli). Same basic 'capability of use' as a Node, but easier to part out to family/friends upgrades later- and a 1/3 less.

Was so frazzled and wired when we got back with the pup after midnight, I finished taking apart my Rti10 to part out (now going towards vet bill, not stereo), took apart and changed up an IKEA shelf, swapped my stereo into said modded shelf, and sat back to survey the carnage

Current state of mind: STATIC

plastic_avatar

I got learnt

- My room is an even worse mess now. Setup panic [hoarder sadface].

- Amp #1 decided it would give me some ground-loop-style hum after I moved it, so amp #2 is batting for it. Good thing I bought it!

- Upgraded system has a heartbeat!

Holy forking shirtballs, @DaveHo.

I learned something very important today:

You just can't know what the gains for upgrading equipment are until you do it (or have experience hearing it. Wow.

Somebody should tell people that^. Not that what they have is awful.

I can't quite wrap my head around what a difference one box made to the sound of my system. It doesn't seem possible. I didn't know. There's no way I could until I heard it. And in a totally non-optimal setting.

The 1C sound like I pulled off their N95 and they can breathe freely for the first time. The SDA was a success from day 1, but this? Nope. This is new.

Being at this stage in the path to better sound is great. Do some people forget that when they get crusty? This is a lot of fun.

I can't wait to get everything put back into place so I can give everything a proper listen.

heiney9

Everything matters, some are large improvements, some are incremental. Most guys here, myself included, are at the incremental, small changes that when added together make a larger difference.

For you, this is just the tip of the iceberg.........you'll be broke all the time....LOL

H9

plastic_avatar

I swear, the 4 people who listened with me the past few weeks for the SDA effect? I want all of them to sit back down and get their unprompted opinions now.

---

I imagine I'll get another boost going from analog out on the CD to dac to pre. At least, based on what others say.

So, do you think my upcoming potential 'Wow' moments are dac, amp, room treatment, and?

If I'm going to Titanic my fun money account, I'd like to plan ahead

What were they for you, @heiney9? Before they got smaller?

heiney9

Better cables, better amp, better pre, better tubes to roll, better streamer, adding linear power supplies getting rid of switching supplies.Swapping cross over components, swapping brick op amps with discrete op amps.

Back along time ago I upgraded cables from Monster to Signal cable that was incremental. Then I got on the MIT bandwagon and the change was phenomenal. But I spent several thousand vs. several hundred.

H9

bcwsrt

I’d probably move the DAC to third in the list, but that’s just me (along with not being able to see what you’re rocking in your signature at the moment). Nevertheless, sometimes you’ll have those “wow” moments and sometimes you won’t. Some things may be planned as “wow” but only end up being incremental. Thankfully, the reverse is also true and keeps things interesting. Good luck with your next steps.