For upgrading a crossover it is best to stick to the original cap, inductor and resistor values. Don't try to second guess the original design! That's just asking for trouble!
Problem Solvers Needed-Got my New XOs installed and am worried....
I think I made a big mistake. I loved the sound of my 1988 Tannoy FSM Dual concentric 15'
speakers. So I thought an expert could analyze the existing XOs and make improvements.
I installed the new XOs expecting a 300-400 hour burn in period. Herein lies the problem.
After 30 hours or so the initial sound has no high end to it. I expected to initially hear sound as good as I had
which would continue to improve as the burn in continued. But no.
I am tempted to reinstall the old XO and kiss off the $2k invested.
I am very open to some suggestions from anyone who has been down this road.
Thanks,
speakers. So I thought an expert could analyze the existing XOs and make improvements.
I installed the new XOs expecting a 300-400 hour burn in period. Herein lies the problem.
After 30 hours or so the initial sound has no high end to it. I expected to initially hear sound as good as I had
which would continue to improve as the burn in continued. But no.
I am tempted to reinstall the old XO and kiss off the $2k invested.
I am very open to some suggestions from anyone who has been down this road.
Thanks,
34 responses Add your response
Do your speakers have controls on them? Is so, mark where they are set and then experiment. You might also experiment with speaker placement. Any change to the system that changes the sound (the reason for the change in the first place) requires other changes to optimize the sound. You need to work with what you now have to get the best out of it. You should also give yourself some time to get used to the new sound. In time you might like the change. Have you talked to the builder about the problems you hear? The builder might be willing to make alterations based on you feedback. |
If you loved the sound of these speakers what were you trying to achieve with this crossover?? I can perfectly understand replacing the stock crossover with higher quality caps, coils, and resistors. But did you give him license to rework the crossover?? That seems like a roll of the dice if so. Did you contact this individual and voice your displeasure? It would be fairly easy in some cases to adjust the resistor values and increase the tweeter output to its original level. Curious how you connected with this "expert." There are a few talented people out there that do this type of work. These people also have many reviews from satisfied customers. |
chorus, Make sure they are hooked up correctly. Without speaker impedances and the values of the components it is impossible to make an accurate statement. Somebody may have goofed up on his math. I would put the old ones back in for the time being. Draw a schematic of the new crossovers with the impedance of the speakers and I'd be happy to run the math for you. You may be able to adjust a value or two and get the right result. |
Some good suggestions; 1) Contact the expert and describe your issues. Crossovers don't need burn-in to sound good, just get better. 2) Good suggestion mijostyn, maybe error. My thought; Hope the original iron core inductors were not replaced with air cores, especially for the low frequency drivers. Iron is usually better than air for woofers. Ask "expert" for a detailed schematic for the crossovers he made for you. |
I will tell you this, I have TRT teflon caps in 3 pairs of speakers I currently own. If you wanted to listen to them you could, I COULDN’T for over 200 hours. 500 hours was considered broke in. So we are clear the manufacture told me to put the speakers under moving blankets for 24/7 with a SS amp and 10-30 watts going through them. Turn them off and on every 2 hours for the DC tickle on startup. It was the only way to break in teflon caps, it worked every time for me. Two pairs of speakers I owned were sold BACK to the manufacture because of the BAD sound, and the customer said so.. "It should sound good when they’re delivered". I agree 100%, but I also paid 50% less for a break in.. I still like teflons the best.. Copper foil are pretty good too for mids in the band pass, a lot easier to break in to. 50 hours tops. I’d make darn sure they were hooked up correct and let them percolate for 2-300 hours... All the time, stay in touch with the guy that sold you the XO. Did YOU asked him to do something silly? OR are the XO changes his idea? His idea, his problem. Your idea, your problem. Be patient.. Regards |
Assuming the new crossover is broken in, modern capacitors and resistors of the exact same values will change the sound, sometimes significantly. It's possible you're used to your original sound and the new parts aren't to your taste. This may be even More true if the crossover topology has also changed. The single most important factor in choosing audio gear is to know your self, especially the factors that must be there and the negative factors that you can't stand. If you don't know yourself well, changes are a case of throwing darts while squinting. |
...now, I'm not brilliant, nor a xover designer, but.... One look at the existing... https://reverb.com/item/10409571-tannoy-fsm-pro-215-studio-monitors-15-dual-concentric-15-walnut-woo... ...and I'd have replaced all existing components with new and Stopped.😬 If a change Had to be made, iyo....a nice outboard active crossover, bit the belt and bi-amp carefully.... Looking over the charts with the ad above, the existing units seem pretty 'exquisite' for those Tannoys'....even the inductors should be approached with care for a revamp...imho, which that + a buck might get you cross-town on a bus. Vintage includes components not really made the same as now. I'd pause at just reconing them, just about that.... They're not speakers anymore....you've got a pair of mistresses...;) Good luck....both are expensive, as you've discovered.... |
I sure would like to see a side by side of the two crossovers, (old and new)THAT would tell me a lot.. Any chance you could post a couple of pic in your "details"? If it's lost the highs its a resistor of some type in the HF path. I'd look where it was hooked to the Highs and see if an inductor or resistor value was added and its GREATER than the original, or as simple as getting the decimal point in the wrong place. If the HF driver wire was hooked up at the beginning of the HF circuit VS the end of the circuit? That would cause the bass to still be going through the HF side. A series XO always coming off the + side and on to the next frequency is pretty easy to see the resistance in the path. Here is the issue I could see in my minds eye. A resistor at the driver that is NOT on the XO. BUT because the resistor was left on or in the HF path the ADDED (but normal) resistor on the new XO doubled the resistance and of course cut the HF signal from getting through. I would look to see if there is a component that you didn't see or were even looking for. Look at the HF driver terminals and make sure there is nothing in the path and if any type of wiring is going to the Negative side of the driver wire all the way to the new XO. Just a thought.. If I was the builder though, I would have wondered WHY I had to add the greater value from the old? The light bulb should have gone off.. WHY? And know a Tannoy XO is not going to be that far off.. IF AT ALL!! Yet the only customer complaint is "It's Old". NOT broke.. old... All I got for no cost. I woke up at 3:30 thinking about that.. And of course it's time to feed the rabbit.. Junior. :-) Regards |
Hello, No worries. If the drivers are OK just go back to the origin values. I would upgrade to better components since you have to do a break in. Did you ask if you have Teflon caps. Maybe they need more time. No permanent damage done just go back to original. Call the person who did the upgrade. If they did require a speacial upgrade he should have told you like Oldhvymec said he had to do on his. I could see why a manufacturer would not put in the Teflon caps. Audiophiles have very little patience. I am a stickler for break in especially on expensive things like audio gear, cars, and motorcycles. It makes a huge difference down the road. We took a road trip and we’re getting 40 mpg in a 2020 CRV touring on the highway. This is not a hybrid. Amazing! |
So, about upgrading XOs... Yes, if you are doing a part swap, then keep the original values. However! DCR in coils and ESR in caps must be maintained, especially in those devices which go to ground, often via a resistor. If you can’t measure that, but only know the uH or uF you are in danger of altering the design. Reducing the DCR or ESR of a part can significantly alter the sound and not for the better. These values are taken into account at design time. You can’t substitute a generic crossover for a previous crossover. The electro-mechanical properties of the speaker and drivers function as a unit. There are times when a speaker’s crossover justifies a complete rethink. I’ve seen this in some Focal and Genesis speakers where impedance drops really did justify a reworking here. I’ve also seen actual speaker designer Troels Gravesen post some really interesting write ups on vintage B&W and Yamaha speakers as well. Go take a look there if you want to know how actual speaker designers think about crossovers: http://www.troelsgravesen.dk/Diy_Loudspeaker_Projects.htm You should be well versed in speaker analysis and crossover design before you attempt this, and even then you must ask yourself, if I’m rethinking this crossover shouldn’t I just build new? And then... well, if you are building new... lots of outstanding kits out there, not to mention speaker drivers waiting to be assembled into a dream setup. As always, I encourage DIY and learning about speaker making. Please do so! Just don't assume things are simpler than they are. :) |
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I had not dreamt I would receive this much great advice. Thanks to all who took time to contribute! Some more detail: The existing system was measured and found to have wide impedance drops-to as low as 1- with frequency responses that were a long way from straight lines. Most of the existing XO parts were from about 1988. The coils were puny. The original system included multiple db settings in 3 areas of treble. You could also run it as a 3-way or a 2 1/2 way. On the computer screen the new system- which eliminates all the old tonal adjustment options- was way simpler and produced straighter frequency responses. The new XO also eliminated the option to bi or try wire the cables. The new XO came in the form of a bag of parts and a wiring diagram of the three speakers. I took these to a guy who truly knows how to assemble things- PHD & former professor who personally assembled 4 Pass DIY amp & pre kits during Covid last year. I was only left to wire the color coded XOs to the speakers. Perhaps I messed up something but I do not think I did. I will try to determine if the tweeters are in fact working or not. As I listen I really do not hear anything in the higher range at all. This is what has me most worried. I was warned that 400-500 hrs of burn in are needed and I am nowhere near that. I have not consulted the fellow who made the new XOs yet for his advice. Thought I would start with you all. I will advise more as it develops. |
I'd stop and make sure I was hooked up right. Now that you've explained what you did. STOP!!! DON'T keep playing I wouldn't want to hurt those drivers.. I don't modify XOs other than the occasional make up cap (by pass is the wrong name) addition. My fear there was a resistor left on a HF driver or that its just wired wrong.. I don't bypass LPads and surely don't go from a tri/bi amp wiring set up to a single amp set up.. WAY to many things were changed.. The LPad removal had to have a little resistor for volume put in place? Wrong value or not hook up when bypassed.. It's in series right? Not a parallel XO.. Again Tannoy are not that far off, they sound to good.. Am I missing something? Less than 1 ohm? You'd be burning up amps. Thing aren't tracking.. for UNDER 1 ohm much less a 2 ohm load.. What kind of amp are you running? :-) Regards |
I may have mis-explained. There were no L-pads before. Just optional db treble settings. Like 0/+3/-3. After a few hours of listening I rolled the big boys into the other room for storage until I had a direction on what to do. My amp is a Pass INT 25. I can send you the before and after graphs if that helps. Not familiar with how to PM people on this forum though. I will disassemble one and try some tests. The two XOs in both speakers are easily removed and shipped. As you say I would have preferred to have maintained the all the original functionality. If you have any suggestions of who to hire to fix this F-up on my part I am listening. Thanks |
Post pics on your profile page, that's the best. I'd be looking at the db selection and what the heck was done there. No Highs, 12 db 2 components, 18 db 3 components, 24 db 4 components. If there is a notch add 2 more to any of the 3. If it has a normal series + feed. Simple question, Did you like the way the speakers sounded before the XO change? Were you having any amp issues like overheating any weird science going on? A Yes, No, answer is dupe the old xo with newer, better parts and be done with it.. Maybe add 2 make up cap in the mids and one in the highs.. The same values just use 2 to 3 to get the total value and it cost a lot less for the better caps and smaller values.. Nutty super voltage is the biggest mistake. 250 vac/dc caps are plenty. Inductors, coils, and resistors.. good parts. Don't mix up left and right either, they were tuned per box sometimes.. different values per speaker, because of driver differences.. It's easy to figure with tone burst and db level. If they are tuned and they are in the wrong box.. LOL 3-8 db difference. Left to Right.. Regards |
Unhook tweeters from the network use a multimeter to test DC of tweeters to see if coils are open this would be the 1st thing I would try. Next, I would continuity test network to see if it has an issue even experts can mess up. Both are easy to do and if you don't know how too many youtube videos on doing so, multimeters are cheap so get one if you don't have one already. |
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Chorus, I am a master with a soldering iron but my knowledge of electronics engineering is.....limited. I can design a cross over which is pretty straight forward in most cases. Dahlquist DQ 10 excepted. It sounds like the difference is beyond anything that break in might overcome. It is also possible the speakers are actually more accurate now and you are just use to listening to the way they were. You could only tell by measuring the loudspeakers. You will have to review thw schematic and the crossover to tell if the math is right and there are no mistakes. Tannoy wisely gave you the flexibility to adjust the speakers for various amplifiers and room conditions and they did it brilliantly with jumpers. I would have maintained that system at least until you knew exactly how you liked them. But, then what happens when you change rooms or amplifiers? |
Two categories of audio "improvement" have 95% of all the total audio misrepresentation attached to them. Wires and capacitors. I mainly fiddle with older Klipsch and new speakers I build for myself and have found a couple of things to be true in my world. A conductor of proper size works just fine and the 12 zip cord I use handles 600 seat theater setups with complete fidelity and no loss. Capacitors do get old and the ESR generally is what drifts out of spec over time. I recap all those crossovers now using Audyn red label or Dayton 1% polypropylene caps. Now there are a ton of people who swear by various expensive caps, especially those who sell them and fru fru fancy crossover builds, but the reality is they are adding distortion to flavor things in a way they like. I use neutral good measuring caps and add flavor other ways if I must. If you liked them when you first got them years ago then caps would be my first suspect for degraded sound today. |
Hi
chorus, some good info supplied and also some not so good. There appears to be a means of adjusting the overall balance of sound with jumpers and something there might be the cause of your problem. What is not the cause is break-in. Initially the components may sound a little off but will not be responsible for lack of top end, something else is. I agree with the suggestions to contact the supplier. If you were supplied a bag of parts he should provide after sales assistance. Measuring 1 ohm is wrong with a Tannoy. I suspect an error. An XO rebuilt should immediately sound better than before if properly done and then will improve a little over time. Generally this involves not changing the circuit's component values, simply replacing the parts. I have upgraded many XOs from a variety of speakers and the results have always been great. I can get as technical as you like but without before and after schematics it's guesswork. erik squires warns against capacitor ESR (equivalent series resistance) and says it can significantly alter the sound. Take no notice as this is a non-issue. ESR comes into play at radio frequencies not audio. What the cap does in an XO is to set the frequency, it is capacitive reactance that is important and the formula for this does not take into consideration any resistance. Xc = 1/2 Pi fc As you can see: There is no R in the equation. Linkwitz, Dickerson and D'appolito know what they are doing. The above person also said go to Troels Graveson for info. I suggest you read up on XO design from the 3 gentlemen I mentioned who are true experts in the field. In fact Linkwitz is famous for his contribution to the well known Linkwitz-Riley XO. Graveson does not acknowledge inductor orientation which from experience makes a difference. Lots of top end speakers don't seem to bother because mounting them the correct way is awkward and therefore expensive to do properly. I have worked on some B &W speakers with coils all over the place. To end off, unless the XO was incorrectly assembled, the guy who sold you the XO should refund you or endeavor to help with your problem. I wish you luck. |
I have been traveling for the past two weeks and left my problem at home. To answer a couple questions: -Yes I loved the sound prior to the XO upgrade attempt. -No I was not having any issues -Yes I marked each left and right side parts. -No I have not done any tweeter testing but when I get back I will. -Yes I plan to take one speaker to my local guru who can tell me what could be incorrectly connected Unless my friend can make the speakers sound good again using the parts I was sold, I plan to follow the advice given above about returning to the existing XOs and simply upgrading them where it makes sense. I will have some updates in another week or so. Thanks! |
A good crossover design would involve more than looking at the speaker specifications and box dimensions, etc. and would involve more than actual measurement of the speaker--you would expect there to be some iterative process involving listening to the result and making changes. Also, it makes no sense to remove driver controls. In properly setting up a speaker system, it is extremely helpful to utilize BOTH speaker placement and control setting to find the best sound for your particular room, your particular speaker location, your sitting position and your taste. You are severely handicapped by a lack of such controls and you may have to resort to more compromises in the ideal speaker location to compensate for a problem that could be ameliorated by controls. I know that there are some "purists" who hate L-pads and such controls, but, if you must insist on removing such items, first set up the speaker for ideal performance, then measure the resistance value of the L-pad at its preferred position before removing and replacing such control with a resistor. |