I just received my T34B tweeters today and got all excited to open them up and admire the fine European craftsmanship, but what i found instead was a back chamber of a driver had come off in transit. The other one still was intact but I only needed to pry very lightly and it came off as well.
The problem is they glued the chamber onto the polished and plated surface of the magnet asy. The magnet surface isn't rough enough to adhere to the adhesive they used so it can get a good bite on it. Needless to say I'm not impressed. At least you guys can see what these things look like inside. There is a 35mm disc of wool felt for dampening inside the chamber. Nothing fancy. I swept both drivers without chambers and they both sound fine, so I'll glue to chambers back on again.
Very disappointing. I thought the Germans know what they're doing with this stuff.
The problem is they glued the chamber onto the polished and plated surface of the magnet asy. The magnet surface isn't rough enough to adhere to the adhesive they used so it can get a good bite on it. Needless to say I'm not impressed. At least you guys can see what these things look like inside. There is a 35mm disc of wool felt for dampening inside the chamber. Nothing fancy. I swept both drivers without chambers and they both sound fine, so I'll glue to chambers back on again.
Very disappointing. I thought the Germans know what they're doing with this stuff.
Attachments
Last edited:
Needless to say, I won't be installing this tweeter without having its own dedicated sub-compartment in the enclosure. I dont trust any adhesive sticking to that slick surface over the long haul. I'll be using a RTV based sealant made for glass surfaces to reattach the chamber.
Believe me, that will happen first thing tomorrow. I should be able to expect more after spending $725 for a pair of tweeters.
My only other guess is US customs opened them up and poked inside, but ithey usually post a note they did that.
I'm pretty sure it's an adhesive issue, due to how easy the other one came apart. That slick surface on the magnet won't hold onto adhesive well and it appears they used some sort of thermo-adhesive ie. hot melt glue. There was zero adhesive residue on the magnet, which tells me it wasn't a good bond to start with.
I'm pretty sure it's an adhesive issue, due to how easy the other one came apart. That slick surface on the magnet won't hold onto adhesive well and it appears they used some sort of thermo-adhesive ie. hot melt glue. There was zero adhesive residue on the magnet, which tells me it wasn't a good bond to start with.
Well at least everyone can see how these are made. Compared to other brands of Be tweeters, these are actually relatively inexpensive. Just one of the new Seas Be domes will cost the same as what a pair of these T34Bs cost me.
Reach out to retailer/manufacturer! See what resolution they offer!
Think you ordered from audio-hi.fi, I booked a set of T25 from them, Fingers crossed!
Think you ordered from audio-hi.fi, I booked a set of T25 from them, Fingers crossed!
Two adhesion failures out of two samples... that is statistically significant. If it is a bad batch of adhesive, then you plan to use an RTV glass window sealant is a good plan. However, it could also be a broken process for surface preparation, in which case the surface could still be unready for adhesive. It may be contaminated with a release agent, a lubricant, or silicone residue. If the surface is not cleaned and prepped, the new adhesive may fail also.
I reached out to Bliesma and got a reply, I quote
"
Thanks a lot for sharing us the link. Hope the customer will contact our dealer and share more details about his problem and we’ll be able to find the solution.
Mit freundlichen Grüßen / With kind regards,
Stanislav Malikov"
"
Thanks a lot for sharing us the link. Hope the customer will contact our dealer and share more details about his problem and we’ll be able to find the solution.
Mit freundlichen Grüßen / With kind regards,
Stanislav Malikov"
The lighting from the camera doesn't show the accurate picture. It's showing alot of surface texture rather than the actual color / hue of the finish itself. It's a chrome or nickel plating, likely to protect the neo magnet material. I'll try to get better pictures in daylight.
I agree about the surface prep issue. The powder coating on the back chamber was clearly not fully cured, as some of it was left behind on the adhesive. The type of adhesive matters too. It was some sort of thermoset adhesive aka hot melt glue. The box was very warm when I got it from delivery, which could have weakened the glue, likely from the 115 degree weather we're having here in AZ.
Either way, I'm going to re-attach the chambers after careful surface prep and go from there. If it's all ok after that, I'll just chalk it up as human error and deal with it. Stuff happens and its a hand made, small batch product. Hopefully the only issue is whats in front of me and life goes on.
I agree about the surface prep issue. The powder coating on the back chamber was clearly not fully cured, as some of it was left behind on the adhesive. The type of adhesive matters too. It was some sort of thermoset adhesive aka hot melt glue. The box was very warm when I got it from delivery, which could have weakened the glue, likely from the 115 degree weather we're having here in AZ.
Either way, I'm going to re-attach the chambers after careful surface prep and go from there. If it's all ok after that, I'll just chalk it up as human error and deal with it. Stuff happens and its a hand made, small batch product. Hopefully the only issue is whats in front of me and life goes on.
They are normally produced and sold in 'matched pairs with consecutive serials, so statistically significant idk, they at least was quite well "matched"l 🤣
A small production batch with glue or surface treatment issues.
Guess the QC procedures does not involve manhandling, so the issue was not noticed.
As for German?
At best assembled in Germany, if not only packaged, branded and shipped etc, like the BMS "made in Germany".
ND magnets are Chinese 99% certainty.
Be diaphragm is Materion foil.
Plastic parts generally are made in China these days, and so on.
The machining finish in your picture, of the machined recess of the pole vent, does not point towards German 5 axis Hermles spitting them out either😊
https://hificompass.com/en/speakers/measurements/satori/satori-tw29bn
The Bliesma T34 is better in every aspect, it is a good option at a lower price if you do not need high spl.
The T34s can play at levels that very few dome tweeters are capable of while sounding good, the distortion down low beats all the competitors too.
Xmax p-p 3mm vs 0,5mm
Flux density 2,2T vs 1,5T
weight 700 grms vs 400.
LE 0,008mh vs 0,2mh
mms 0,26g vs 0,46g
Sd 10,5cm2 vs 9,6 - Yet the T34B has significantly better off axis behavior, and the A's wide dispersion rivals several 0,75"s.
Eff: 97,5 vs 95db - more real 94 vs 96 ish.
A small production batch with glue or surface treatment issues.
Guess the QC procedures does not involve manhandling, so the issue was not noticed.
As for German?
At best assembled in Germany, if not only packaged, branded and shipped etc, like the BMS "made in Germany".
ND magnets are Chinese 99% certainty.
Be diaphragm is Materion foil.
Plastic parts generally are made in China these days, and so on.
The machining finish in your picture, of the machined recess of the pole vent, does not point towards German 5 axis Hermles spitting them out either😊
https://hificompass.com/en/speakers/measurements/bliesma/bliesma-t34b-4
https://hificompass.com/en/speakers/measurements/satori/satori-tw29bn
The Bliesma T34 is better in every aspect, it is a good option at a lower price if you do not need high spl.
The T34s can play at levels that very few dome tweeters are capable of while sounding good, the distortion down low beats all the competitors too.
Xmax p-p 3mm vs 0,5mm
Flux density 2,2T vs 1,5T
weight 700 grms vs 400.
LE 0,008mh vs 0,2mh
mms 0,26g vs 0,46g
Sd 10,5cm2 vs 9,6 - Yet the T34B has significantly better off axis behavior, and the A's wide dispersion rivals several 0,75"s.
Eff: 97,5 vs 95db - more real 94 vs 96 ish.
Last edited:
Thanks for doing that. I'll let them know.
Having a materials engineering background, I can clearly see its a surface prep and adhesive application issue. They should have used some form of bolt on /screw on attachment to secure the chambers. Just adhesive alone is not enough for something like a high vibration area prone to weakening by heat and vibration in transport and use. I could have planned to use a more permanent type of adhesive, but that will hinder serviceability of the driver in thr future, which Is important to retain.
Thats why I bought them, mainly because of the potential dynamic range they have while being low in distortion. Thata a hard feat to achieve with a hifi type driver.
Why not take the oppurtunity to experiment before you glue em back on permanently at least on one?
A larger damped enclosure for example to see the differences.
And Augerpro already have a good amount of nice WG designs for them, there also exists a few other options, if that's to your taste.
As for being critical of German craftsmanship, I'm German myself, coming from a family of patent owners with engineering history. There is a certain amount of pride when I look at what has been achieved by Germans in terms of fine mechanica technology ie optics, small scale machinery and precision. My expectations are very high of products that are assembled there. Even though other materials, processes and machining could have been done elsewhere in the world, the ultimate final QC should be done by the end assembly person. They should catch engineering and assembly issues before they get in the hands of the customer. Thats really on them as a company, regardless of where else the other parts and labor come from.
I'm not gonna mess with proven performance, but I can appreciate where you're coming from. Some more dampening or a larger back chamber can hurt more than it could do good on a driver of this level of engineering. I also don't want to void any warranty if there's any other problems I can't see yet. Maybe a better back chamber geometry could have lowered THD even more, ie a rear phase plug in the back chamber like Seas uses on the T35C002, a very good driver i also have a lot of experience with. I have a huge soft spot for larger diameter HF domes. Even the lowly audax TW034 is a great.performer.for its cost and age in design. It too benefits from a few little extra things. Its really a fantastic underrated driver with far more to give than originally designed.
- Status
- Not open for further replies.