Speakerlab S7s Rebuild and Modding (Ribbon Tweeter Model)

[Bratwurst7s]

So this is why I went external and modular. It took just a few minutes today to glue in a new block and connector on each tweeter board, and after letting the glue dry while running errends it only took a few more minutes to move a wire over to the new connector and add a padding resistor in series.

I went here to do the calculation...

http://www.sengpielaudio.com/calculator-Lpad.htm

...and had some 1.8ohm resistors on hand from an earlier order, and the calculator showed that for a 7.1ohm driver 1.84 ohms of padding would drop the tweeter 2db. Going with 2db was just a guess, and I had 1.8 and 1.0 ohm 10watt resistors.

Sounds quite a bit better now, the tweeters aren't setting my teeth on edge anymore. I think that the mid will need some adjusting, it's a bit bright, but for now I'm just going to leave it so for a while and do a bunch of listening.

I think that the next step will be to go ahead and order the alluminum frame mids that I was looking at when I have some money saved, and then decide if I want to change the mid section to a bandpass (probably will).



Cheers,
James

 

[Bratwurst7s]

OK, today I went ahead and added 1/2 ohms more padding to the mids, should result in about 1.3db down. Sounds a bit better now, the drivers seem more equal in output. But it also seemed to reveal (to my ears at least) that the mid is just trying to work where it shouldn't, and I'm gonna have to bandpass the mid. There's an upper harshness coming out of the mid now that grates the nerves.

What with the Foster ribbons dropping off below 6khz I can understand why they let the mids run fullrange on the upper end originally (to try to fill in the hole), but with the response of the MHT-12s they are now trying to work in the same range and it hurts the ears there now.

But in passages where that harshness isn't promenant the speakers sound fantastic, bass is not so muddy, I think that I'm on the right track. Time to think this through over the next month or 2 as I save some funds, but the plan at this time is to redesign the mid board as a bandpass after buying 2 new Wavecor mids.



Cheers,
James

 

[Spalls]

James:

Just out of curiosity, are you consistently listening to the same music as you troubleshoot, or listening to a wide variety of sources?

 

[Bratwurst7s]

James:
Just out of curiosity, are you consistently listening to the same music as you troubleshoot, or listening to a wide variety of sources?

Hi Spalls, sorry for taking so long to answer, I missed that you had posted.

The answer is both. I have a set of CDs that I always use for testing, and have also been listening to random cds just because.

Chicago's first album,
Supertramp COTC,
Dire Strait's first,
Rory Gallagher's first,
It's a Beautiful Day's first.

Some or all of those 5 are my everytime set, depending on how much time that I have. Then I go from there. Some Led Zep, mabye some Sabbaton for something heavy, some Social Distortion, lately been listening to Rod Stewert's Every Picture Tells A Story a lot (again ). Etc.

I decided today to order the caps and coils to add a lowpass to the midrange to make those boards into a bandpass. There is just too much coming from the mid on the upper end and I can't leave it like that even if I plan on changing things later.

Since Europe Audio is on my blacklist now I started looking around for another source of Jantzen air core coils and found an outfit called Fidelity Components Shop up in Estonia. They have an even larger selection than Europe Audio and better prices. So I'm trying them out and placed an order this morning. We'll see how they do.

Cheers,
James

 

[Bratwurst7s]

A couple of days ago I got an email from Fidelity Components Shop about my order. They told me that they had made a mistake and ordered the wrong parts. Made sure that I knew that they had made a typing error and didn't try to shift the blame or make excuses. They also offered 2 different subs to replace my order, more expensive Mundorf 0.22mH coils, at no extra cost to me, or that if I was willing to wait 3-5 extra days they would reorder and ship the Jantzens.

I like this. I like their honesty. Anybody can make a mistake but they stepped up, took responsability and offered a set of choices to deal with the issue. I wrote them back and explained that the order wasn't urgent, that I'd prefer the Jantzens and had no problem waiting, and that I was pleased with their honesty. I have more than enough to do with other projects to keep me busy another week.

Oh, I forgot to mention that when I placed the original order they informed me immediatly that some items weren't in stock and would need a couple of weeks to order. I had no problem with that and was happy that they at least made a quick info dump.

Cheers,
James

 

[Spalls]

Glad to hear that things are working out for you. Order problems can be very frustrating, especially when you feel that you are not getting the straight story.

 

[Bratwurst7s]

Glad to hear that things are working out for you. Order problems can be very frustrating, especially when you feel that you are not getting the straight story.

Thanks Spalls. I got a post yesterday that the order has shipped. So it should be here tomorrow or Saturday. With a little luck I'll be installing the parts this weekend.

Cheers,
James

 

[Bratwurst7s]

Well my parts arrived yesterday, everything in good condition. So that's one attaboy for Fidelity Components Shop so far. Today they got installed and now the mid section is a true bandpass. The schematic shows how things stand now.

The boards are starting to look like something that would make Dr. Frankenstein proud but I can live with that as long as they take me where I want to go. And they are. LOL, I ignored my normal test cd's and played the Dead's "Workingman's Dead" and Ten Years After's "A Space In Time" first, just because. I'll conform to the norm as the week moves along.

Anyway, this is nice. I'm headed in the right direction. The overdriven harshness is gone now and the mid to upper area is butter smooth now. It sounds really really nice up there now. €23 well spent I think.

But getting that out of the way has revealed a bit of bass boom now. That's not completely unexpected, XSim showed a roughly 7db hump centered at about 240hz. So that's the next issue to address. Time to learn about notch filters I guess. Or look deeper into switching over to L-R 4th order crossovers.

I'm also seriously considering replacing the dacron fill that is now in the cabs with fibreglass. €25 will buy enough to do any number of speakers so that's probably next up on the todo list. As well as looking into replacing my current padding resistors with true L-pads.



Cheers,
James

 

[Bratwurst7s]

So now that I've been listening to the speakers for almost a month now the following comes forth. 1) I tend to get too entheusiastic about every change and tend to be not objective enough. 2) My feeling after settling down was that the highs were too high and the lows were too boomy. But over time I realized that I was just having to turn it up too much to get the mids to perform like I wanted. And the soundstage and depth were now lacking compared to the old crossovers.

So the mids were underperforming. Today I removed the extra 0.5 ohms of padding that I had previously added to the mids. That resulted in a surprising improvement in overall sound. The 1.8 + 0.5 ohms of resistance should have given about 4.7db of padding to the mids. Removing the 0.5 ohms should have brought it down to about 3.9 db of padding. There was a surprising difference/improvement in sound for that 0.8 ohms of padding but I think that the mids still need to come up a bit more.

I'm thinking now of going to a true L-Pad and swapping the series 1.8 ohms to an L-Pad with 1 ohm series + 7.5 ohms parallel which should lower the padding to 3.1 ohms. I have no idea if that will be to much but will find out.

In any case things are improving. I spent about 4 hours listening today and am very pleased with the current sound, just a bit more to go I think. I also re-arranged the room a bit allowing the speakers to be spaced another ca 10" apart, and moved them about 6" farther away from the back wall. That improved things a bit also.

Cheers,
James

 

[markdi]

I bet they sound great

 

[Bratwurst7s]

I bet they sound great

Hi Mark,

They are getting there. Still some tuning to do. When I first had the new crossovers in they sounded very different than with the originals. Objectively, not as good in some ways actually. Now that I'm slowly getting them step by step where they should be they are now sounding better than before, with the exception that I think that the mids are still playing too low.

Once I get to a point where I'm very satisfiyed I'll probably pull the mid boards and remake them in a more organized/clean layout, and get the remaining resistors off the wood supports and on some plastic supports/insulators. That was a mistake.

How are your das7's coming along? did you ever recap them?

Cheers,
James

 

[markdi]

no I have not done anything to them yet

 

[Bratwurst7s]

Last night I remembered that I still have some 2.2 ohm Mox's in the parts box. I had originally installed 2x 3.9 ohm moxs on the mids to duplicate the 2x 4ohm wirewound resistors in the stock crossovers. (and for some brainfart reason have been calling them 1.8 ohms of padding instead of 1.95 ohms)

So today I pulled one of the 3.9 resistors and paralled the remaining one with a 2.2. I just did a listening test with Steely Dan "Can't Buy A Thrill". This is getting very very good now. Really goosebump good. Very smooth and one doesn't notice the individual drivers now. After lunch they are going to get a bit of a workout.

Cheers,
James

 

[Bratwurst7s]

After the last listening session I dicided to trade out the 2nd (last) 3.9 ohm resistor on the mid with a second 2.2 ohm. So now there is only 1.1 ohms on the mid. For my ears this is somewhere around perfection now. For now anyway this is what I'm going to live with. And I'm very pleased with the results so it's easy to live with them.

Over the next weeks or month I'll make plans of the external crossover boxes and a list of materials for anyone that's interested.

Cheers,
James

 

[Bratwurst7s]

LOL, every time that I listen to the speaks for a few weeks I decide that the mids need just a bit more volume. So 2 days ago I reduced the mid padding to 0.7 ohms and now I think that I'm done. At least I'm even more happy with the sound than I was before.

Cheers,
James

 

[Bratwurst7s]

So, an update.

In the past I had been using a variety of source components. A Sony DVD player, the Asus Xonar Essence STX sound card in my pc and a LG blu-ray player. Then I decided that I'd like to try a real CD player and a friend gave me an Onkyo DX-6900 to play with. It sounded pretty good and I used it since around the beginning of this year. But the last few months it wasn't sounding so good so I decided to look for something new/better.

http://www.audiokarma.org/forums/showthread.php?t=672930

I looked around quite a bit and settled on looking for a Denon DCD-1290- It seems to have been their flagship in the '92-'94 time frame, has a laser that can still be bought for reasonable money, and is available on the 'bay for reasonable (aka in my low budget) prices. I ended up buying 2 of them.

But after hooking it up after the 1st one arrived I was a little dissapointed. Overall the sound seemed more detailed, Highs and lows seemed more, well just more. But imaging and mids were actually lacking in comparison to the Onkyo.

http://www.audiokarma.org/forums/showthread.php?t=674109

So thinking about what I've already gone through concerning the mids today I removed the last padding that was on the Wavecors and replaced it with a jumper. Whoah Mama!

Now we are another step along the way. It just keeps on getting better. I am so damn happy with these speakers at this point that I don't really have the words to describe it. They sound incredible. Which is in itself surprising. Considering that these are the first crossovers that I have ever built it is obvious that they must be far from perfect.

When I load the crossover plan in XSim and look at it, well a person can just laugh. It shows a huge peak at the low crossover point, which seems to have fallen closer to 300hz than the planned 350hz, and there is another hump at the upper cross point, and a nasty dip between the low and high. The frequency curve looks simply despicable.

And yet, the speakers sound fantastic. Much better now than I ever remember. They're blowing me away they sound so good, I just can't stop listening to them. I wonder what more can be pulled from them?

Cheers,
James

 

[sc427]

I just sold one of my pairs of 50's to my ex.... We bought them together back in 96' and she always loved them. I get buy back rights so I'm happy. I passed on a pair of Super 7's on Craigslist. I was twitching but my wife wasn't really thrilled with getting another pair of speakers.... They were all original with nice oak veneer cabs . The 10" and 61/2 needed to be refoamed.... $175 was all they were asking..... Kicking myself..... But I really don't need any more speakers. Glad to hear that yours are sounding great....

 

[Bratwurst7s]

I just sold one of my pairs of 50's to my ex.... We bought them together back in 96' and she always loved them. I get buy back rights so I'm happy. I passed on a pair of Super 7's on Craigslist. I was twitching but my wife wasn't really thrilled with getting another pair of speakers.... They were all original with nice oak veneer cabs . The 10" and 61/2 needed to be refoamed.... $175 was all they were asking..... Kicking myself..... But I really don't need any more speakers. Glad to hear that yours are sounding great....

Please PM me if the 7s are still available. I have a friend down near Portland that might be very interested in them.

Cheers,
James

 

[Bratwurst7s]

It's been a while now since I've done anything with the speakers except listen to them. I got pretty sidetracked with a vacation to the Pacific NW, my CD player project...
http://audiokarma.org/forums/index.php?threads/dennon-dcd-1290-mod-thread.688774/
...a new (to me) Yamaha RX-V3900 amp, and some other projects. But today I ordered a new set of mids. 2x Wavecor WF166TU01's. Essentially the same speaker as what I have now but with a nice heavy cast allu frame.

http://www.wavecor.com/html/wf166tu01.html

€369 for 2 midranges. I must be nuts. Well, ok, yes I am, at least concerning my speakers anyway. But it's not like the WF160WA01's will go to waste. The plan is to eventually buy another MHT-12 tweeter, put the 160's in series, build a cab and use them as a new center channel speaker.

I'm also going to buy a bale of fibreglass and refill both speakers with that at the time that I swap out the mids.

Cheers,
James

 

[Bratwurst7s]

I got an email yesterday at 3:31pm stating that my mids had shipped. This morning around 10:00 they were at my door. Damn that's fast. I ordered them from Iris Strassacker Lautsprechershop. http://www.lautsprechershop.de/ I've placed perhaps 10 or so orders with them so far and am pretty pleased with their service. I can often find a bit better prices from other outfits but often buy from them anyway because their service and communication is first class. (no affiliation, just stating the facts)

These are some nice looking speakers. It'll be a week or so before I get them installed but will post more pics when that happens.



Cheers,
James