The crossover can affect the woofer, usually from the inherent series resistance of and inductors in series with the woofer. Usually heavy gauge or iron cored inductors are used in those positions to minimize the resistance. Other than that, in most cases the woofers are used at full level.
That's because of a couple reasons, but mostly because usually woofers are the least sensitive components in a set, so the tweeters and/or mids are attenuated down to the woofer levels.
That's because of a couple reasons, but mostly because usually woofers are the least sensitive components in a set, so the tweeters and/or mids are attenuated down to the woofer levels.
I thought so. This is the script so far. I have a pair of Acoustic Energy Radiance Ones. About 12 months ago I upgrade the tweeter to Scanspeak 3004/66000. The was in big improvement and I was very happy with the results, so I decided to upgrade the mid bass unit and this is were it's all gone wrong. I bought a couple 15/w8530koo driver in fitted them into my existing cabinets using the existing x/overs. This didn't work well, is was lacking bass and lower midrange, so I returned them because I couldn't get a x/over. Anyway, Because the Scanspeak mid woofers are so highly rated I bought two more, but with x/over. I fitted them thinking this would give me really nice sounding bookshelf speaker.
However, it's not worked out, they are still sadly lacking bass and Lower mid range. With original Acoustic Energy mid bass drivers the bass is fine. Any thoughts ?
Ron
However, it's not worked out, they are still sadly lacking bass and Lower mid range. With original Acoustic Energy mid bass drivers the bass is fine. Any thoughts ?
Ron
The crossovers were supplied with the 15w mid bass drivers. They were specific to the 15w and the 3004/6600 tweeters. Just for the sake of clarity, I had no problem with the bass using the Acoustic Energy pressed alloy drivers. I'm going to have play around with the positioning and see how it goes. The only other thing I can think of is the size of the box. Having said that, there are quite a few kits using a box about the same size as mine.
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Galu - OP's previous thread may be informative. 
OP: A couple of things may be contributing:
1: have the new drivers been run in at all yet? Many people find that drivers do not perform at their best when fresh out of the box, but need some time running to settle in to their proper performance.
2: WRT the Scan's not working with the original crossover, it may be that the AE drivers needed less Baffle Step Compensation than the Scan's (perhaps due to an inherently falling upper mid response). If that were the case the minimal (or potentially absent) BSC in the original crossover would have left the Scan's sounding very light in the bass & low-mids in comparison.
I confess, I'm not enough of an expert to say wither of these factors is definitely at play, but they're both possibilities.
OP: A couple of things may be contributing:
1: have the new drivers been run in at all yet? Many people find that drivers do not perform at their best when fresh out of the box, but need some time running to settle in to their proper performance.
2: WRT the Scan's not working with the original crossover, it may be that the AE drivers needed less Baffle Step Compensation than the Scan's (perhaps due to an inherently falling upper mid response). If that were the case the minimal (or potentially absent) BSC in the original crossover would have left the Scan's sounding very light in the bass & low-mids in comparison.
I confess, I'm not enough of an expert to say wither of these factors is definitely at play, but they're both possibilities.
Gala, this is a different setup now. I couldn't get a x?over for that setup so I bought two 15w/8530 from Wilmslow and they supplied the x/overs Ok. a couple of things after further investigation.
Fist off, the speakers are in phase. However when playing a 100hz test tone it didn't sound right, both the tweeters and the bass units were not sealing properly. I could feel the draft around the edges. This is because the Acoustic Energy cabinets are made of compressed cardboard and when you screw the screws in in it leaves a raised l lump around each screw. So I need to fix.that. The other thing was the wadding is blocking the vent tube, so I've moved that. I did expect some compromise with the cabinet, but I thought it would only be minor. Anyway, I'll fix these and see how it goes.
Thanks for all you input, personally I think the x/over needs to tame the tweeter a bit to bring things more into balance?
Ron
Fist off, the speakers are in phase. However when playing a 100hz test tone it didn't sound right, both the tweeters and the bass units were not sealing properly. I could feel the draft around the edges. This is because the Acoustic Energy cabinets are made of compressed cardboard and when you screw the screws in in it leaves a raised l lump around each screw. So I need to fix.that. The other thing was the wadding is blocking the vent tube, so I've moved that. I did expect some compromise with the cabinet, but I thought it would only be minor. Anyway, I'll fix these and see how it goes.
Thanks for all you input, personally I think the x/over needs to tame the tweeter a bit to bring things more into balance?
Ron
Hi Ron! Perhaps the following may help:
To reduce the 4 ohm tweeter output by 4dB you can wire a 6.8 ohm resistor (R2) in parallel with the tweeter terminals then place a 1.5 ohm resistor (R1) in series with the parallel combination as shown in the attached L pad circuit diagram.
Both resistors should be at least 10W ceramic wire-wound resistors like the ones available here: Ceramic Resistors
Attachments
Ok! for those that are interested about my disastrous foray into self build speakers here is the latest update. I sealed the drive units and moved the wadding around and there was a slight improvement.
However, the sound was still awful, it's all mid range, they sound like a huge transistor radio.
The efficiency ha increased by a least 6db, possibly more. They are flat out at 10 o-clock, with the old drivers and x/over it was more like 1 0-clock/ 2 o-clock on the volume control. A massive increase in efficiency. Pink noise tests are very harsh, never heard pink noise like this before. In summery the upgrade has provided me with a VERY efficient, but very harsh sounding loudspeaker. So, I put the old x/over back and the Acoustic Energy mid/base and it is now silky smooth, the mid range is slightly recessed, but it is a very musical and foot tapping sound.
Something must be wrong with the x/over. How could two top class drive units sound so bad?
The reason I swapped out he original tweeter and replaced with the Scanspeak 3004/66000 was because I always felt the top end was a tad dull. The upgrade to the Scanspeak tweeter has fixed that, but it has effected the mid range slightly. I thougt that buy buying the Scanspeak mid bass and ax/over the match I would have really nice sounding bookshelf speaker. And what have I got? the worst speaker I have ever heard and that is no exaggeration..
However, the sound was still awful, it's all mid range, they sound like a huge transistor radio.
The efficiency ha increased by a least 6db, possibly more. They are flat out at 10 o-clock, with the old drivers and x/over it was more like 1 0-clock/ 2 o-clock on the volume control. A massive increase in efficiency. Pink noise tests are very harsh, never heard pink noise like this before. In summery the upgrade has provided me with a VERY efficient, but very harsh sounding loudspeaker. So, I put the old x/over back and the Acoustic Energy mid/base and it is now silky smooth, the mid range is slightly recessed, but it is a very musical and foot tapping sound.
Something must be wrong with the x/over. How could two top class drive units sound so bad?
The reason I swapped out he original tweeter and replaced with the Scanspeak 3004/66000 was because I always felt the top end was a tad dull. The upgrade to the Scanspeak tweeter has fixed that, but it has effected the mid range slightly. I thougt that buy buying the Scanspeak mid bass and ax/over the match I would have really nice sounding bookshelf speaker. And what have I got? the worst speaker I have ever heard and that is no exaggeration..
I haven't looked up curves on the woofers you tried, but it's possible they have big cone breakup resonances in the midrange, well above their levels in the woofer frequency range. Some of the fancier wider-band woofers (such as the Acoustic Elegance and some others) can have quite a bit of output above their targeted band, so need the crossover to be adapted more aggressively to not feed that band into the woofers.
I'm going to give the supplier a ring tomorrow. I asked them to provide two drive units and a crossovers the match my existing tweeters. I know the cabinet is not exactly the same size, but it is within a few mm. Mine 320x185x250 The cabinet Wilmslow use is 330x200x255.
So not that much difference, there is no way it's the cabinet that's at fault. This is a really poor speaker. The thing is, it's not just that the sound is a bit bright or the bass lacking a bit.. These are so way off you would not know where to start with a critical assessment.
What I can't understand is the massive increase in efficiency. I'll let you know how I get one.
I've been a hi-fi hobbyist since the mid seventies. Never hear anything like these though.
So not that much difference, there is no way it's the cabinet that's at fault. This is a really poor speaker. The thing is, it's not just that the sound is a bit bright or the bass lacking a bit.. These are so way off you would not know where to start with a critical assessment.
What I can't understand is the massive increase in efficiency. I'll let you know how I get one.
I've been a hi-fi hobbyist since the mid seventies. Never hear anything like these though.
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Ok, further update, just to recap. I was using Acoustic Energy Radiance Ones with a Scanspeak 3004/66000 tweeter. This worked fine, but the tweeter was so good I decided to upgrade the mid/bass driver from the pressed alloy to Scanspeak 15w8530koo. So I ordered a pair of Scanspeak mid/bass units, with a x/over to match my existing Scanspeak 3004/6000 tweeters.
I fitted these and the sound was as described in previous posts. Awful. So put the speakers back to were they were before I started and everything was fine. Anyway, I decided to put the Scanspeak mid/bass drivers back in with the the original Acoustic Energy x/overs, and guess what, It's fine, they work really well with the AE x/over. The bass is has should be, better the the AE alloy drivers if anything. So there you go, the problem is the x/over. Here is a pic of the x/over and the AE x/over
I fitted these and the sound was as described in previous posts. Awful. So put the speakers back to were they were before I started and everything was fine. Anyway, I decided to put the Scanspeak mid/bass drivers back in with the the original Acoustic Energy x/overs, and guess what, It's fine, they work really well with the AE x/over. The bass is has should be, better the the AE alloy drivers if anything. So there you go, the problem is the x/over. Here is a pic of the x/over and the AE x/over
Attachments
![IMG_0549[1].JPG](/community/data/attachments/685/685005-479ad895df4b529d761dc3386eb3c9cc.jpg)
![IMG_0531[1].JPG](/community/data/attachments/685/685033-2d83863804247d3ca4b09330822dfa5c.jpg)
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The crossovers are entirely different (you just have to look at the capacitor values) so no wonder they give wildly different results!
The supplier may have made a mistake when they designed the crossover to match the Scanspeak 15W/5530 to the Scanspeak D3004/6600.
They are very helpful so please contact them for advice.
I've linked to details of your drivers so that all can see what you are working with!
Scanspeak 15W/8530K00 MidWoofer - Revelator Range
https://www.falconacoustics.co.uk/downloads/Scanspeak/d3004-660000.pdf
The supplier may have made a mistake when they designed the crossover to match the Scanspeak 15W/5530 to the Scanspeak D3004/6600.
They are very helpful so please contact them for advice.
I've linked to details of your drivers so that all can see what you are working with!
Scanspeak 15W/8530K00 MidWoofer - Revelator Range
https://www.falconacoustics.co.uk/downloads/Scanspeak/d3004-660000.pdf
Thanks Galu, these mean nothing to me, I have no idea about electronics and x/overs.
All I know is that the AE one works and the other doesn't.
Wimslow are very experienced, I bought a pair of Kef Reference Ones from them when they were in Wilmslow.many moons ago. There must have been a slip up,somewhere
All I know is that the AE one works and the other doesn't.
Wimslow are very experienced, I bought a pair of Kef Reference Ones from them when they were in Wilmslow.many moons ago. There must have been a slip up,somewhere
The day I visited the original Wilmslow location all those years ago I had the speaker demonstration room and switching facility all to myself. The staff just left me to get on with it! I was like a kid in a candy shop! I remember that of all the speaker kits I auditioned that day, the Wilmslow Audio version of the LS3/5a sounded the best to my ears. I now regret not buying the kit, but I did go home with ready assembled cabinets for my Wharfedale 12" drivers instead! 
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