I received the replacement pair today. I think they just sent me back the same exact pair I returned. The two impedance curves lay directly over the first pair.
Funny thing is I just received an email inviting me to write a review about these tweeters.
I received the replacement pair today. I think they just sent me back the same exact pair I returned. The two impedance curves lay directly over the first pair.
Funny thing is I just received an email inviting me to write a review about these tweeters.
I sent a very professional email to tech@parts-expess.com complete with my invoice numbers and screen shots of the DATS impedance measurements of both pairs. That was only mid afternoon today. Hopefully they will respond soon.
PE tech replied to my email. They checked their current batch of RST28F and found more units that "didn't meet their expectations". So they've asked me to return the second pair. They will either give me a refund and help me "select" another model tweeter or I can wait while they work with their vendor to fix the issue. I can't complain about how they've handled this. I think I'll just move on though.
When you redesign a great $50 tweeter and price it at $30 something has to give. It certainly caught my attention when both Jeff B. and Curt C. went with Morel tweeters in their NLA RS28 redesigns.
I got curious and ran a sweep on the pair I have next to my desk:
Bullshit, you ask me.
I'm not going to worry about it, I bought them when they were $25/ea, but it is still a stretch to say they had production processes ready. They do appear to be reasonably close from a sensitivity perspective, but might actually require different XO values.
Here is a random pair of the recently on-sale DA25 (I purchased four, grabbed two for this):
The impedance peaks are generally a better fit for each other, but there is an obvious difference in impedance - which probably equates to a db or more of difference in sensitivity.
I will have to measure the other pair of RS28F and the other pair of DA25 to see if I can match pairs a little closer, but I am disappointed in Dayton Audio. Over the last several years I have measured a lot of their drivers and found many of them to be pretty nuts-on, generally within 1-2% of advertised. Their inability to accurately clone the original RS28 is an issue as they do not currently have any dome tweeters in this range otherwise. Maybe they should stick to stealing Morel designs.
The Tymphany is concerning, as well. Although I paid, what - $12/ea for them on-sale they are still in that price range where it is very easy to move to a different tweeter if QC is not there.
In any event, I have two pair of each and these measurements confirm my intended use - as a throw-away tweeter in quickie designs. I see no reason to go through the trouble of dealing with returns when I can just throw a design together with some inexpensive MCM clearance drivers and be done with it.
The Tymphany DX25BG60 (beast mode tweeter) pair also exhibits some issue with one of them:
I might spend some time breaking them all in and re-sweep, the DX25 with the normal resonance is well broken in, the other is out of the box. However, they are almost a perfect match for each other otherwise.
The measurements I took of the DX25 indicate it is a very worthy successor to the original RS28. It has a smooth response, and very low distortion above 1500Hz. I would have no problem crossing it as low as 1500 in a small bookshelf that will be SPL limited via woofer excursion, and it will likely handle 2000 all day and all night in a large system.
My hope is the DA and RS drift closer together and the resonance clears up on the DX25after a break-in , but that takes a little time to set up in the ol' Nerdery so it will not be right away.
I'm very surprised to see that problem with the Peerless. Could be something as simple as VC lead dressing, damping material that's cut wrong or not quite sitting where it should be. Still, it hints there might be lax QC oversight in the China factory. I hope this is not indicative of where their entire product line might be headed. I better measure my DA25's and see how they look.
A PE Tech sent me an email today saying they refunded the RST28F amount back to my credit card. He didn't send me a UPS label or say anything about returning them. So if I see the money is refunded then I'm going to tear them apart and see if I can figure out what went wrong and fix them.
I was at PE's website this morning and noticed that the RST28F show out of stock and due in 6-14-19. They must have pulled all their stock after measuring bad ones.
I tore one of mine apart tonight. I had to tear off the felt dome that was glued on under the dome and over the pole vent. That cross shaped pole vent has a black plastic insert that fills the ends of the cross and leaves a round pole vent. The resulting pole vent has an open cell grey foam cylinder inserted. But one thing I found as a possible issue is there is a ton of extra glue that I assume is used to adhear the plastic insert. It over flowed and blocked off at least half of the pole vent (directly below the felt dome). I'm hoping it's as simple as removing that excessive glue to bring these babies into spec.
Well removing the extra glue didn't solve the problem. I then removed the foam plug from the pole vent. No change. Then I stuffed some cotton in the pole vent. That reduced the lower frequency peak and increased the higher frequency peak. I'm sure if I stuffed enough cotton in there the lower peak would completely disappear and I'd have a tweeter with no rear chamber and a Fs of ~1100 Hz.
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Funny thing is I just received an email inviting me to write a review about these tweeters.
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Bullshit, you ask me.
I'm not going to worry about it, I bought them when they were $25/ea, but it is still a stretch to say they had production processes ready. They do appear to be reasonably close from a sensitivity perspective, but might actually require different XO values.
Here is a random pair of the recently on-sale DA25 (I purchased four, grabbed two for this):
The impedance peaks are generally a better fit for each other, but there is an obvious difference in impedance - which probably equates to a db or more of difference in sensitivity.
I will have to measure the other pair of RS28F and the other pair of DA25 to see if I can match pairs a little closer, but I am disappointed in Dayton Audio. Over the last several years I have measured a lot of their drivers and found many of them to be pretty nuts-on, generally within 1-2% of advertised. Their inability to accurately clone the original RS28 is an issue as they do not currently have any dome tweeters in this range otherwise. Maybe they should stick to stealing Morel designs.
The Tymphany is concerning, as well. Although I paid, what - $12/ea for them on-sale they are still in that price range where it is very easy to move to a different tweeter if QC is not there.
In any event, I have two pair of each and these measurements confirm my intended use - as a throw-away tweeter in quickie designs. I see no reason to go through the trouble of dealing with returns when I can just throw a design together with some inexpensive MCM clearance drivers and be done with it.
The Tymphany DX25BG60 (beast mode tweeter) pair also exhibits some issue with one of them:
I might spend some time breaking them all in and re-sweep, the DX25 with the normal resonance is well broken in, the other is out of the box. However, they are almost a perfect match for each other otherwise.
The measurements I took of the DX25 indicate it is a very worthy successor to the original RS28. It has a smooth response, and very low distortion above 1500Hz. I would have no problem crossing it as low as 1500 in a small bookshelf that will be SPL limited via woofer excursion, and it will likely handle 2000 all day and all night in a large system.
My hope is the DA and RS drift closer together and the resonance clears up on the DX25after a break-in , but that takes a little time to set up in the ol' Nerdery so it will not be right away.
FS is a little high, it's supposed to be 721Hz, but at least they match fairly well.