dean_g
Agent
- Joined
- Dec 8, 2001
- Messages
- 38
Well, I suppose the thread title could have also been called 'LeMarcus at the mercy of a two-channel loon".
I wanted to put this post in the DIY section -- but it appears it's mostly subwoofer related, and so I decided just to stick it in here figuring it would get more exposure anyways.
I work with LaMarcus, or "Marcus" as I know him. We cross paths on the weekends as I am heading out the door and he's heading in. I'm pretty much a solder slinger, and since the weekends can be kind of slow -- I'll usually bring in something related to my latest project to help keep me busy. Marcus noticed my newly rebuilt Dahlquist DQ-10 crossovers sitting on the desk, and the next thing you know -- I'm toting one of his JBL S26's home for a little experimentation. Trusting soul isn't he?
A little about myself: I'm two-channel only. My system consists of a pair of Klipsch RF-7's, Quicksilver M-60 mono-blocks (parallel push-push pull, ultralinear EL-34 tube amps), Cary SLP-94 tube preamp, and Sony 9000ES DVD/CD/SACD player. I have another system, but it changes so often it's not worth going into. It's the "test" system -- the one that is most subject to my tortures.
I would do multi-channel if I could afford it. Maybe someday. Right now, I'm happy squeezing as much out of two channel as possible. To do multi-channel at the level of performance my 2-channel system has -- I would go bankrupt.
I also like vintage gear. You know, the stuff you wanted while you were in high school -- but there was simply no way you could afford it.
One of my favorite all time speakers is the Dahlquist DQ-10. I have just finished restoring my third set. The first set was hell -- because I knew what I wanted to do, but had no skill-sets for doing it. I spent a month reading about circuits, and studying the crossover boards. It is without a doubt one of the strangest crossovers ever put on a board. More time was spent learning how to solder. At some point, it all clicked -- and I got to work. I took them down to the last screw and built them back up. Surrounds, crossovers, wiring, wood work -- every part was restored or replaced.
Having been around the DQ-10 most of my life, I was very familiar with the sonic signature, and the thing that struck and startled me -- was how much smoother and refined mine sounded than the stock rendering. I had chosen the RelCap Multi-Cap PPMFX metallized polypropylene capacitors to replace the worn out mylars on the stock boards -- not because I thought they would improve the sound all that much, but simply because they would fit on the boards the best. The experience was quite a revelation.
This led to quite a bit of research on the parts themselves, and of course more experimentation. Insanity set in and I decided to rebuild the boards in my RF-7's -- a speaker I was already happy with. When I pulled the original boards out, which had parts mounted on a PCB -- I knew there was no way I was going to get what I wanted to use on them. So, I built new ones.
http://forums.klipsch.com/idealbb/do...-02E02476A8B7}
Again, easily heard improvement in every area: Tighter bass, better retrieval of ambiant information, no grain, sparkly treble, decay on the cymbals, etc. Of course, these boards were near cost no object boards.
Next, I took on my Dad's old JBL Aquarius S109's -- which had been sitting in storage for 10 years. I pulled them out and gave them the complete workover. Same result. Almost got to see my old man cry.
So -- now I'm a believer. Take almost any commercial speaker, yank the crap -- and you are going to get a much better speaker for very little investment.
What are some objections to this line of thinking?
You didn't make them "better", you just made them "different".
A valid statement in part. Yes, they become "different". However, there is not a change in signature. They don't take on a totally "new" sound. There is a slight shift in signature because of the additional clarity and dynamics. A welcome trade off.
The engineers know what they are doing, and that speaker was designed to sound a certain way. The parts chosen contribute to that "sound".
This is actually true, and why modding can be dangerous. It can be hit and miss. However, my personal experience so far has shown improvement each time I've done it. The speaker sounds cleaner, and can play louder before distortion artifacts draw attention to themselves.
If it could have been done better -- it would have been.
This one connects to the objection before it. Something to keep mind is that the best engineering department is constrained by the marketing department, heh? Hey man, it's all about demographics, price points, WAF, etc. These folks know you just sunk $3000 - $4000 on your big screen, and you're scraping together every last cent you can find for the sound system. Trust me on this -- corner cutting is the name of the game in most consumer mass market products.
Let me show you:
The JBL S26
Not a bad sounding speaker. Quite good actually considering its size. I'm kind of old school. I like bigger drivers, and the more the better. Large drivers have less IM distortion at any given volume. The JBL S26 6.5" woofers look itty bitty to me.
I pull one out of the cabinet and I'm surprised by the weight. JBL makes nice drivers. The driver exudes quality. Nice cast frame, well made through and through. The tweeter is sweet too -- I dig the phase plug. So, this is where the money went. This is good -- because crossover components are much cheaper than good drivers. The cabinet material is partical board, though the fit and finish is very good.
So, what's left?
What you are looking at are the parts I replaced from the PCB crossover I just rebuilt for Marcus. If you know something about crossovers, then you'll notice there are no inductors. I do not mess with inductors. The combination of mH and DCR are critical in relationship to the drivers. If I were completely rebuilding these boards from scratch, and not using the original PCBs, I would probably replace the inductor for the woofer with a 14AWG Solen Perfect Lay. Besides, this is primarily a HT system with an SVS sub bringing up the bottom -- so we can let this go.
At any rate, what do we know about the parts in the picture? Well, we have two electrolytic capacitors, two cement resistors, and two 'do drop in' bypass caps (there is only one in the picture because the other one is MIA in my work room
Total cost of these parts (retail mind you)?
electolytic #1.....40 cents
electrolyic #2.....45 cents
resistor #1........39 cents
resistor #2........39 cents
bypass cap #1......11 cents
bypass cap #2......11 cents
$1.85
There are two inductors, each costing about $2. Throw in the PCB and the wires -- and you have a board that's worth less than $10.00 Don't laugh, even you guys with the high priced stuff might be surprised to find out what's in your speakers. I can safely bet they're not film and foils
End Result
The picture shows the completed board with two of the old parts for scale. I had really wanted to use Audience Auricaps, but they are kind of fat, and there was simply not enough room on the board to fit them. I consider the Auricap the best metallized polypropylene there is, but it was apparent I was going to have to use something different. I had to find a decent metallized polypropylene that would fit.
Bottom of the board -- big cap for scale.
I was also somewhat indecisive as what to do about the small bypass caps. I'm not a big advocate of the principle. The idea behind it is to run a very good quality, small value, high voltage cap -- in parallel with a low quality, large value cap. In theory, the signal will pick up the signature of the high value, high quality cap, and mask the sub-par signature of the low quality cap. I say use the right cap to begin with -- and you don't have to deal with the issue. Many people do not agree with me. Many people actually prefer the sound of bypassing, and reason that it is not necessary to spend the money on a large value quality cap if you can get the same signature with bypassing. Since I'm basically a hard head, I'm not about to budge on this -- even though I have no experience with bypassing -- until now.
JBL boxed me in. The PCB is designed for the bypass caps, and I can't use the big caps because of the space limitation on the board.
I decide that maybe Marcus can have his cake and eat it too. If bypassing really works (and JBL certainly seems to think so, since they employed the principle in an attempt to "bypass" the electrolytics)-- then I'll take it to the highest level possible.
Once I find the polypros I know will fit -- I then order a batch of the AudioCap Theta film and foils. These are considered by many (including myself) to be the best caps on the planet. They are expensive, but the bypass values are small enough, that in conjuction with the polypros -- I was able to keep the cost at about the same as the Auricaps would have cost without the bypass caps. If the principle really works -- I will have been schooled by JBL, and Marcus will have some dyamite sounding monitors.
Also notice in the pic that I like hot glue. I like it a lot. I damp the crossover parts with it as much as possible without inhibiting heat dissipation. The inside of a speaker box is a violent place.
The Cabinet
Worth doing anything here? You bet!
I talked Marcus into the Deflex Panel mod.
Deflex is the bomb. It's simply the best single tweak you can do to a speaker. I'm serious -- it's that good. TV should line one of his SVS subs with this stuff -- I think it would blow him away.
JBL makes you pay the price for getting into their speakers. I reach in and pull out what I believe to be the standard fare -- and end up with fiberglass all over me. I may charge Marcus extra for "pain and suffering".
At any rate, there is plenty of stuff on the net about Deflex, and it's the last thing I have to do before I put the speaker back together. Looks like total time spent on the speaker mod will come in at about an hour and half. Marcus will have around $50 into each speaker.
I will not be making any comments regarding my impressions relating to the sound of the modded S26 until after Marcus has had an opportunity to assess for himself what he thinks. I did tell him that if he doesn't like it -- I will change it back for free (which means I'm out $1.85
Dean
I wanted to put this post in the DIY section -- but it appears it's mostly subwoofer related, and so I decided just to stick it in here figuring it would get more exposure anyways.
I work with LaMarcus, or "Marcus" as I know him. We cross paths on the weekends as I am heading out the door and he's heading in. I'm pretty much a solder slinger, and since the weekends can be kind of slow -- I'll usually bring in something related to my latest project to help keep me busy. Marcus noticed my newly rebuilt Dahlquist DQ-10 crossovers sitting on the desk, and the next thing you know -- I'm toting one of his JBL S26's home for a little experimentation. Trusting soul isn't he?
A little about myself: I'm two-channel only. My system consists of a pair of Klipsch RF-7's, Quicksilver M-60 mono-blocks (parallel push-push pull, ultralinear EL-34 tube amps), Cary SLP-94 tube preamp, and Sony 9000ES DVD/CD/SACD player. I have another system, but it changes so often it's not worth going into. It's the "test" system -- the one that is most subject to my tortures.
I would do multi-channel if I could afford it. Maybe someday. Right now, I'm happy squeezing as much out of two channel as possible. To do multi-channel at the level of performance my 2-channel system has -- I would go bankrupt.
I also like vintage gear. You know, the stuff you wanted while you were in high school -- but there was simply no way you could afford it.
One of my favorite all time speakers is the Dahlquist DQ-10. I have just finished restoring my third set. The first set was hell -- because I knew what I wanted to do, but had no skill-sets for doing it. I spent a month reading about circuits, and studying the crossover boards. It is without a doubt one of the strangest crossovers ever put on a board. More time was spent learning how to solder. At some point, it all clicked -- and I got to work. I took them down to the last screw and built them back up. Surrounds, crossovers, wiring, wood work -- every part was restored or replaced.
Having been around the DQ-10 most of my life, I was very familiar with the sonic signature, and the thing that struck and startled me -- was how much smoother and refined mine sounded than the stock rendering. I had chosen the RelCap Multi-Cap PPMFX metallized polypropylene capacitors to replace the worn out mylars on the stock boards -- not because I thought they would improve the sound all that much, but simply because they would fit on the boards the best. The experience was quite a revelation.
This led to quite a bit of research on the parts themselves, and of course more experimentation. Insanity set in and I decided to rebuild the boards in my RF-7's -- a speaker I was already happy with. When I pulled the original boards out, which had parts mounted on a PCB -- I knew there was no way I was going to get what I wanted to use on them. So, I built new ones.
http://forums.klipsch.com/idealbb/do...-02E02476A8B7}
Again, easily heard improvement in every area: Tighter bass, better retrieval of ambiant information, no grain, sparkly treble, decay on the cymbals, etc. Of course, these boards were near cost no object boards.
Next, I took on my Dad's old JBL Aquarius S109's -- which had been sitting in storage for 10 years. I pulled them out and gave them the complete workover. Same result. Almost got to see my old man cry.
So -- now I'm a believer. Take almost any commercial speaker, yank the crap -- and you are going to get a much better speaker for very little investment.
What are some objections to this line of thinking?
You didn't make them "better", you just made them "different".
A valid statement in part. Yes, they become "different". However, there is not a change in signature. They don't take on a totally "new" sound. There is a slight shift in signature because of the additional clarity and dynamics. A welcome trade off.
The engineers know what they are doing, and that speaker was designed to sound a certain way. The parts chosen contribute to that "sound".
This is actually true, and why modding can be dangerous. It can be hit and miss. However, my personal experience so far has shown improvement each time I've done it. The speaker sounds cleaner, and can play louder before distortion artifacts draw attention to themselves.
If it could have been done better -- it would have been.
This one connects to the objection before it. Something to keep mind is that the best engineering department is constrained by the marketing department, heh? Hey man, it's all about demographics, price points, WAF, etc. These folks know you just sunk $3000 - $4000 on your big screen, and you're scraping together every last cent you can find for the sound system. Trust me on this -- corner cutting is the name of the game in most consumer mass market products.
Let me show you:
The JBL S26
Not a bad sounding speaker. Quite good actually considering its size. I'm kind of old school. I like bigger drivers, and the more the better. Large drivers have less IM distortion at any given volume. The JBL S26 6.5" woofers look itty bitty to me.
I pull one out of the cabinet and I'm surprised by the weight. JBL makes nice drivers. The driver exudes quality. Nice cast frame, well made through and through. The tweeter is sweet too -- I dig the phase plug. So, this is where the money went. This is good -- because crossover components are much cheaper than good drivers. The cabinet material is partical board, though the fit and finish is very good.
So, what's left?
What you are looking at are the parts I replaced from the PCB crossover I just rebuilt for Marcus. If you know something about crossovers, then you'll notice there are no inductors. I do not mess with inductors. The combination of mH and DCR are critical in relationship to the drivers. If I were completely rebuilding these boards from scratch, and not using the original PCBs, I would probably replace the inductor for the woofer with a 14AWG Solen Perfect Lay. Besides, this is primarily a HT system with an SVS sub bringing up the bottom -- so we can let this go.
At any rate, what do we know about the parts in the picture? Well, we have two electrolytic capacitors, two cement resistors, and two 'do drop in' bypass caps (there is only one in the picture because the other one is MIA in my work room
Total cost of these parts (retail mind you)?
electolytic #1.....40 cents
electrolyic #2.....45 cents
resistor #1........39 cents
resistor #2........39 cents
bypass cap #1......11 cents
bypass cap #2......11 cents
$1.85
There are two inductors, each costing about $2. Throw in the PCB and the wires -- and you have a board that's worth less than $10.00 Don't laugh, even you guys with the high priced stuff might be surprised to find out what's in your speakers. I can safely bet they're not film and foils
End Result
The picture shows the completed board with two of the old parts for scale. I had really wanted to use Audience Auricaps, but they are kind of fat, and there was simply not enough room on the board to fit them. I consider the Auricap the best metallized polypropylene there is, but it was apparent I was going to have to use something different. I had to find a decent metallized polypropylene that would fit.
Bottom of the board -- big cap for scale.
I was also somewhat indecisive as what to do about the small bypass caps. I'm not a big advocate of the principle. The idea behind it is to run a very good quality, small value, high voltage cap -- in parallel with a low quality, large value cap. In theory, the signal will pick up the signature of the high value, high quality cap, and mask the sub-par signature of the low quality cap. I say use the right cap to begin with -- and you don't have to deal with the issue. Many people do not agree with me. Many people actually prefer the sound of bypassing, and reason that it is not necessary to spend the money on a large value quality cap if you can get the same signature with bypassing. Since I'm basically a hard head, I'm not about to budge on this -- even though I have no experience with bypassing -- until now.
JBL boxed me in. The PCB is designed for the bypass caps, and I can't use the big caps because of the space limitation on the board.
I decide that maybe Marcus can have his cake and eat it too. If bypassing really works (and JBL certainly seems to think so, since they employed the principle in an attempt to "bypass" the electrolytics)-- then I'll take it to the highest level possible.
Once I find the polypros I know will fit -- I then order a batch of the AudioCap Theta film and foils. These are considered by many (including myself) to be the best caps on the planet. They are expensive, but the bypass values are small enough, that in conjuction with the polypros -- I was able to keep the cost at about the same as the Auricaps would have cost without the bypass caps. If the principle really works -- I will have been schooled by JBL, and Marcus will have some dyamite sounding monitors.
Also notice in the pic that I like hot glue. I like it a lot. I damp the crossover parts with it as much as possible without inhibiting heat dissipation. The inside of a speaker box is a violent place.
The Cabinet
Worth doing anything here? You bet!
I talked Marcus into the Deflex Panel mod.
Deflex is the bomb. It's simply the best single tweak you can do to a speaker. I'm serious -- it's that good. TV should line one of his SVS subs with this stuff -- I think it would blow him away.
JBL makes you pay the price for getting into their speakers. I reach in and pull out what I believe to be the standard fare -- and end up with fiberglass all over me. I may charge Marcus extra for "pain and suffering".
At any rate, there is plenty of stuff on the net about Deflex, and it's the last thing I have to do before I put the speaker back together. Looks like total time spent on the speaker mod will come in at about an hour and half. Marcus will have around $50 into each speaker.
I will not be making any comments regarding my impressions relating to the sound of the modded S26 until after Marcus has had an opportunity to assess for himself what he thinks. I did tell him that if he doesn't like it -- I will change it back for free (which means I'm out $1.85
Dean
MM
