Open Source "Tower XL"

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no not the efficiency/sensitivity of driver or a passive system, overall SPL in active system ( should have added that to avoid misunderstanding ). I might be wrong but back in my studio monitor days I read that they simply feed more power to drivers (in active systems) to have more max SPL, so you have a very high 110db SPL in a very small package that still goes down to 35-40Hz, I know this ahs nothing to do with this thread but so was my point.
one question tho, I did ask this before and it is off topic but how did Zaph got 92db sensitivity from a 90db woofer in SB12.3 ?
 
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AE TD6M reportedly has some unusual dip around 900-1K Hz range, AE stock FR pic shows some dip in that area but apparently people are experiencing even deeper dip, looks like there are some fixes around this but not sure if this changes things or not.
4-Way Series Crossover. Accuton and Acoustic Elegance Drivers
Lambda TD6 tests on the way

I believe they have changed the design some what since then, but I would not trust that mid without some current measurements and user feedback.
Their woofers I trust because there is lots of user feed back, but the mids too much of a mystery for me at this point.
Why not one of the pro sound 6" mids? Looks like B&C have several interesting ones.
 
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Hopefully they did fix it by now, Cousin Billy showed how he did get rid off that dip (both here and on AE forum) apparently reflections from the magnet causes the dip and he explained how he got rid of that with a piece of Sorbothane, but the pic he shared does not help much, this goes back to 2015 tho and I could not find any newer info if they fixed the issue or not, they probably did otherwise people would still talk about it. but Cousin Billy mentioned that he liked it better than Accuton C158.
at the end of mentioned AE forum John from AE posted:
"There are clearly some changes as seen in the measured frequency response seen. I still have not been able to recreate this on a test baffle here. It is seen only in cabinets with approximately the same depth. The position of the dip does move with respect to depth of the cabinet though. Most all of these absorption techniques will help lessen any reflection off the inside of the cabinet. There could be a reflection from the lip around the spider, however adding a small amount of foam should not have that significant of an effect then with a resonance at that frequency.

At this point though, we have a new frame we are going to be using as the old one is no longer available. I will get some good measurements of the new driver on a test baffle soon."


Unfortunately this is the last post and no updates since hopefully the posted FR plot in TD6M is the updated measurement, the DIP is there but not significant.
 
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About that dip around 700Hz, spider/frame reflections was suspected. I wouldn't trust Cousin Billy's sorbothane result too much though...

Most likely measuring a 6" driver with large plug at 3" distance is the main reason for the bad dip in first link. Even plug shape makes differences! Still, there is dip even in AE's owm data. This is partly compensated with typical baffle step hump.

Notice the difference in response nearfield (yellow)/1m (red)! TD6M - the Lambda Series Little Brother - AE Speakers
TD6M-response-curves-mid.PNG


Wolfgang Klippel tells something here ... https://www.klippel.de/fileadmin/_migrated/content_uploads/KLIPPEL_Sound_Radiation_Poster_01.pdf
Check this too, by Peter Larsen ! YouTube
 
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Hopefully they did fix it by now, Cousin Billy showed how he did get rid off that dip (both here and on AE forum) apparently reflections from the magnet causes the dip and he explained how he got rid of that with a piece of Sorbothane, but the pic he shared does not help much, this goes back to 2015 tho and I could not find any newer info if they fixed the issue or not, they probably did otherwise people would still talk about it. but Cousin Billy mentioned that he liked it better than Accuton C158.
at the end of mentioned AE forum John from AE posted:
"There are clearly some changes as seen in the measured frequency response seen. I still have not been able to recreate this on a test baffle here. It is seen only in cabinets with approximately the same depth. The position of the dip does move with respect to depth of the cabinet though. Most all of these absorption techniques will help lessen any reflection off the inside of the cabinet. There could be a reflection from the lip around the spider, however adding a small amount of foam should not have that significant of an effect then with a resonance at that frequency.

At this point though, we have a new frame we are going to be using as the old one is no longer available. I will get some good measurements of the new driver on a test baffle soon."


Unfortunately this is the last post and no updates since hopefully the posted FR plot in TD6M is the updated measurement, the DIP is there but not significant.

If the magnet/spider/basket system creates any significant acoustic reflections, they would show up at higher frequencies. 900 Hz wavelength is 0.38m, and that's too much to fit into the driver, even when you just take half the wavelength. Also, if the dip changes with different enclosures dimensions, it's not reflections happening in the driver.

If the datasheet does not show the dip, I'd trust that and get one of those drivers. If you find the dip is there on an open test baffle (or whatever they used to get the curves in the datasheet) you simply return the thing saying that it does not match the datasheet specs.
 
AE TD6M reportedly has some unusual dip around 900-1K Hz range, AE stock FR pic shows some dip in that area but apparently people are experiencing even deeper dip, looks like there are some fixes around this but not sure if this changes things or not.
4-Way Series Crossover. Accuton and Acoustic Elegance Drivers
Lambda TD6 tests on the way

Only on a large IEC baffle this dip can be observed in a correct way.
All measurements in a cabinet have an extra baffle step boost in the SPL, which depends on the cabinet size and shape.
So at this moment I only take the SPL curve published on the AE website as a reference, because I suppose it has been measured on a large IEC baffle.
 
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I did some research on the TD6M, if the dip is caused by basket (or frame) as AE and some other users claimed (pic 1), all the measurements including the one I posted in #125 and Juhazi in #129 is from the old basket, the old basket had 6 pols (or legs or posts...) connecting the magnet to front part and the new one has 4 with slightly different shape (pic 2). so hoping that was it, but weirdly there are no reports or feedback for newer basket since. if we don't hear back from AE, we may have to look for another mid. what is the minimum sensitivity required for the mid to go with TD15X (if) ?
 

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I did some research on the TD6M, if the dip is caused by basket (or frame) as AE and some other users claimed (pic 1), all the measurements including the one I posted in #125 and Juhazi in #129 is from the old basket, the old basket had 6 pols (or legs or posts...) connecting the magnet to front part and the new one has 4 with slightly different shape (pic 2). so hoping that was it, but weirdly there are no reports or feedback for newer basket since. if we don't hear back from AE, we may have to look for another mid. what is the minimum sensitivity required for the mid to go with TD15X (if) ?

Conform the TSP of the AE TD15X, it will have a sensitivity of 90.1 dB in full space.

For the speaker we have in mind it will radiate in full space up to about 100 Hz and in half space above 400 - 500 Hz.
So if midrange and woofer are crossed low, suppose 200 Hz, the midrange also has to operate a part in the transition zone from full to half space.

A rough estimation is a sensitivity of 93 - 94 dB in half space for the midrange, to cover some tolerances on woofer and midrange and to choose a low crossover frequency.

Before ordering drivers, we can do a study to check this all w.r.t. sensitivity and excursion...
 
thanks Paul, yes I like lower crossed mids better too,
In different posts and forums AE claims that the dip issue was from the cab and not the driver same as mbrennwa suggested, and they said that they couldn't measure the dip in their test baffle.
TD8M also looks like a good candidate as well, no reported issues and curve looks better too, also only 20$ difference, but looks like it needs to be crossed lower than 2k.
but if we didn't hear back from AE we have two options:
1-finding alternative drivers, finding a good 6-8" midwoofer should not be a problem (maybe the woofers too ?).
2-get the AE drivers and measure it and hope they work well.
I have no problem w either of the options and as much as I want to go with AE but I just do not like the fact that AE does not answer back before ordering the drivers and makes me think that we may have harder time returning the drivers if it didn't work out. just thinking out loud looking for feedback.
 
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I want to go with AE but I just do not like the fact that AE does not answer back before ordering the drivers and makes me think that we may have harder time returning the drivers if it didn't work out. just thinking out loud looking for feedback.

If something does not conform to the specs given in the datasheet, any reputable seller should take it back and give you a refund or provide a replacement that works as described in the datasheet. No need to be worried as long you get your stuff from a reliable source.
 
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