Speakerlab S7s Rebuild and Modding (Ribbon Tweeter Model)
- Thread starter Bratwurst7s
- Start date
You are 100% correct. Every step has been a joy so far. The learning experience alone has been worthwhile.
James
OK! I just made payment on a pair of new 10" woofers. As mentioned earlier the decision fell on the Scan-Speak 25W-8565-00. They seem to fit the parameters better than anything else that I could find. I should have them in a week or so.
Cheers,
James
Cheers,
James
I just got an update from the outfit where I ordered the woofers. Apparently they only had 2 in stock and noticed some damage to a tinsel lead on one so there will be a week delay while they order new ones. They apologized for the delay but the way I see it they just saved me 2 weeks and a lot of aggravation by doing a QC check before shipping. This is the same company where I ordered my tweeters and midranges. I'm starting to like them a lot.
Cheers,
James
Cheers,
James
The woofers finally arrived this morning. I didn't have time today to do anything other than open the box and check their condition, everything looks ok. Sure is an enormous magnet, much larger than the soon to be history previous replacements. I'm hoping that I'll have time tomorrow to install them.
Cheers,
James
Cheers,
James
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I have nerver been able to find any specs for the poly cone - foam surround W1008P that were OEM in this model so have had to fall back on the '80 specs for the W1008R (paper+polylam cone). The W1008R specs vary considerably over the years, and some of the spec sheets That I've found (including the 1980 one) were poorly scanned, making them very difficult to read.
Finding something that comes close to matching (on paper) has been difficult to say the least. Here goes... SL = W1008R, SS = W25/8565-00
Fs: SL = 16.7hz / SS = 20hz
Qts: SL = 0.412 / SS = 0.41
Qms: SL = 2.0 / SS = 5.4
Qes: SL = 0.52 / SS = 0.44
Bl: SL = 8.3 / SS = 8.2
Rms: SL = 2.59 / SS = 1.00
Mms: SL = 49.23 / SS = 43
Cms: SL = 1.84 / SS = 1.47
Sd: SL = 340mm³ / SS = 330mm³
Vas. SL = 305L / SS = 225L
DCR: 7.0 / SS = 5.5
Voice coil Dia. SL = 1.5"/38.1mm / SS 42mm
Voice coil overhang - Xmax: SL = 6.1mm / SS = 6.5mm
Sensitivity: SL = 89.5db / SS = 88db
Power handling (continous): Both = 100w
I've been unable to find a woofer that matches perfectly. Some had better sensitivity but then had much higher Fs. One had a matching Fs but much different Qts. One looked very interesting overall but had a much greater flange dia, requiring filing a bite off of the flange to fit the mounting hole. Etc, etc. I'm also not entirely sure which specs to place the most weight on. I choose to look at overall Qts, Fs, Xmax and ease of mounting.
In the end my choice landed here. Some specs differ considerably but it looked to me to be overall the best compromise. I'll have them installed in the next few days and find out how they sound. I'm assuming that the values of the existing Zobel are now suspect and I need to measure the impedance of both woofers (10" + 12") and recalculate.
Next on my purchase list is a copy of DATS V2 and a UMIK-1 usb mic. I have (or have access to) a freq generator and Fluke ScopeMeter, so over the next few months it's finally time to learn how to use this stuff. After that the plan is to approach a second generation crossover around the end of the year.
So, thoughts? Am I making any major thinking failures here? If nothing else I'm having fun, and the speakers are so far sounding better with each step.
Cheers,
James
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GuyK
Addicted Member
I think you are on the right track, and I also think that the x-over will need to be reworked slightly to bring the all the new components into alignment...rather like you're planning. But I'm certainly no expert in these matters. I just have enough understanding of the basics to muddle my way through things.
OK. My wife has been very supportive of my newly rekindled audio craze so I promised her that I would finish her new kitchen before installing the new woofers. The last 2 cabinets took less time than I thought so I was able to move forward in the sound dept today after all.
In the 1st pic the Scan-Speaks are on the left, the now retired semi-unknown 10"ers on the right.
I wasn't at all sure just what to expect. I certainly didn't expect such serious improvement. First on was my standard test cd, the first Chicago album, followed by Kenny Wayne Sheppard's "Live On".
Whow! It isn't just that there is substantially more base (there is), or that it's going deeper (it is), but that it is so much cleaner and more intense. More punch. This is really nice. Another step forward and it just keeps getting better. Once again I'm very happy. Time to start tuning and find out how much more can be squeezed out of these things.
The last week also saw the retirement of our old Sony 29" Trinatron TV and DVD player, sat receiver, and the old Phillips CD player that I was using, replaced by a Samsung 48" LED TV and LG BP-620 Blu-Ray player. That stuff was changed out before the woofers, with a couple days of audio listening in between to get used to the difference between the old/new disk players. The next few weeks will see the TV/stereo stand getting replaced with a better open shelf setup. Things are jumpin'.
Cheers,
James
In the 1st pic the Scan-Speaks are on the left, the now retired semi-unknown 10"ers on the right.
I wasn't at all sure just what to expect. I certainly didn't expect such serious improvement. First on was my standard test cd, the first Chicago album, followed by Kenny Wayne Sheppard's "Live On".
Whow! It isn't just that there is substantially more base (there is), or that it's going deeper (it is), but that it is so much cleaner and more intense. More punch. This is really nice. Another step forward and it just keeps getting better. Once again I'm very happy. Time to start tuning and find out how much more can be squeezed out of these things.
The last week also saw the retirement of our old Sony 29" Trinatron TV and DVD player, sat receiver, and the old Phillips CD player that I was using, replaced by a Samsung 48" LED TV and LG BP-620 Blu-Ray player. That stuff was changed out before the woofers, with a couple days of audio listening in between to get used to the difference between the old/new disk players. The next few weeks will see the TV/stereo stand getting replaced with a better open shelf setup. Things are jumpin'.
Cheers,
James
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Yeah, that's were I'm at too. A basic concept of where I want to go, with a very rudimentary ability to get there. Trial and error. It's been a lot of fun so far, and it's probably good that my limited funds are forcing me to go slow. More time to try to get my old brain working. Thanks for the encouragement, I need all that I can get.
Cheers,
James
One other thought. As I was searching through the specs of different woofers and finally started to pay attention to frequency response charts I started to notice that the peak sensitivity of all the speakers I was looking at were well above the 350hz crossover point that these model 7's have.
When I started to look at the sensitivity in the 350hz and below range the Scan-Speaks started to look a lot better than speakers with a higher stated sensitivity, and have a better (lower) rolloff, and had the lowest Fs in a speaker that appeared to be suited to a closed box in terms of Qts.
In any case since my last post I've listened to Supertramp "Crime Of The Century", Europe "Bag Of Bones", the new remaster of Led Zep I, and Ten Years After' "A Space In Time". The improvement in bass response is crazy good.
Cheers,
James
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While not directly related to my speakers, I finally finished the new stereo/TV stand that I've been working on. What makes it relevant is that I now have room for a second power amp, as well as an active crossover, and even an OPPO BDP-105. Long term dreams, but you gotta start somewhere. I'll start a thread about the project in the DIY forum in the next day or 3.
Cheers,
James
Done: http://www.audiokarma.org/forums/showthread.php?p=8031690&posted=1#post8031690
Cheers,
James
Done: http://www.audiokarma.org/forums/showthread.php?p=8031690&posted=1#post8031690
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Thank you. They are keeping me happy. Building the new stand kinda used up my fun funds for this month, but I should be able to buy the UMIK-1 mic that I want next month and start testing.
Cheers,
James
Valveglow
Super Member
Good show, James. Personally however, I would choose the volume control and start crankin'!
Oh heck, I'm doing that already! But I want to do some real balance measurements on the different drivers, as well as some room measurements. My ears are telling me that they are quite well balanced now, but I'm wanting to know exactly before I start to get into buying new crossover components. Plan is Sept a mic, and in Oct Dayton's DATS V2, if they have it for sale by then. Shooting for a Dec buy of poly caps and better air-core coils, especially for the woofers. I already have a selection of 10w MOX resistors.
Cheers,
James
I have REW. I'm hoping that's enough. I haven't actually messed with it yet, except to confirm that it will run in Linux.
I have 2 separate goals, and didn't state clearly enough where I'm headed. The mic and REW are for measuring freq response, sensitivity, and room response. DATS I want to use to measure driver parameters, I'm especially hoping that it can measure impedance for calculating the values to determine what changes the woofer zobel needs, if any. Nice to see you back, been a while.
Cheers,
James
A friend of mine uses an older version of the PE woofer tester for getting driver data. I don't remember what he's got for frequency response capture. He's a fan of series crossovers and has developed his own software for making the design simulations. I think he uses MathCad. He's a mathematician, so it all works for him.
You've put a lot of good work into your project and I hope you will enjoy them for years to come.
Have fun,
John
You've put a lot of good work into your project and I hope you will enjoy them for years to come.
Have fun,
John
Someone here at AK recommended DATS as a great program, and since then I've heard other good comments about it so that was/is what I was/am planning on buying. When I checked Dayton's website it stated that it's currently out of production, waiting on a new version. So I sent them an email last month asking about "when" and they replied that it would be released at the end of July. I haven't seen it yet but am hoping that by October when I can afford it it will be available.
Again, REW was recommended here on the forums somewhere. And I've downloaded Jeff Bagby's crossover design software, and it seems to run in Linux using Libre Office Calc. I haven't gotten very far with that yet.
I don't have the brain to do the math for myself. I've been reading Rod Elliot's pages over and over again and I'm still understanding only a very small percent of what he writes. I also have a copy of "The Loudspeaker Design Cookbook", same answer, a small part of it is sinking in.
I had never seriously considered bi-amping until ConradH but a bug in my ear, now I'm glad that Speakerlab put the woofer in parallel with the mid/tweeter. That makes it easy to mod if I do decide to go that route.
Oh well, one small step at a time. At least I'm having fun.
Cheers,
James
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