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Midrange advice

poppop

poppop

pfm Member
Guys

System, which Ive had for a number of years, is Linn Keltiks with klimax crossovers, and 8 avondale power amps (200/220 boards)
Midrange is: Seas M15CH002 E0043-06S - Excel Series (crossover points: Bass to mid 118Hz, mid to treble 2400Hz)

Room size is c. 9m x 5m. and believe it or not I love the sound!

However, Im going through a youth revival and listening to a lot of Budgie. The problem is that on tracks like Breadfan, Infor the Kill, Parents and Black Velvet Stallion the midrange cone is slightly unhappy, having a tendency to almost meet me half way up the room!! "Er indoors" suggests turning it down but wheres the fun in that!

I dont have a clue about "parameters" and all the various specs, but Im ok with a bit of DIY.

Any suggestions for an alternative midrange that can cope with a bit more welly!!?

Thanks
Steve
 
118hz is a low crossover point for a 5" mid, but it has very good xmax and power handling, so It should be capable of going pretty loud.

The loudest speakers I've owned had a 10" Eminence deltalite 2510 midbass driver, coupled with an 18sound horn tweeter. A good horn tweeter can go loud as hell, without distortion. Couple that to a good pro-audio driver like the Eminence, and it's surprising how loud they can go.

As for replacing the mid driver. Loudspeaker design isn't easy. Read here - https://www.diyaudio.com/community/...-design-your-own-speaker-from-scratch.332688/
 
Don't forget that although you say the Bass/mid crossover point is 118Hz the woofer will still be contributing to the sound until its level is about -25dB down.

I personally doubt that your lower crossover point is 118Hz, much more likely to be about 375Hz in which case the case driver will contribute up to about 900Hz

If however you are determined to try a new mid then try the Satoti 16cm, available as woofer or mid, or if you are rich there are a couple of Scan speak drivers that might Work for you.

I would buy a USB measuring Microphone, turn the Bass power amp Off and measure what the mid is doing. Then turn the mid amp Off, bass one ON and measure what the Bass driver is doing
 
Hi
CPG, I picked up the figures regarding crosover points from the WAM but of course not available now!
However, I think the poster was "Sunbeam" and may be a poster on here (?) I believe he was/is doing work regarding the Linn Exakt system, BUT I could be wrong.
Could you point to a particular scanspeak unit that would be best match?
Thank you.
 
poppop said:
Could you point to a particular scanspeak unit that would be best match?
Click to expand...
None of the Scan-speak drivers will be a drop in fit. It'd be a proper faff to re-cut the baffle. I advise against it, as the change will be permanent.

Your best bet is another Seas. I suggest the ER15RLY, which is a drop in replacement. It shares the same basket, if not the motor, of the M15. The E15 has a slightly wider range, higher (peak) power handling, and longer excursion. The only trade offs are 1dB less sensitivity and perhaps not as good a motor as the M15.
 
Thanks James.
Again, your comments reminded me of something I read on the Lejonklou forum (now they really are "Linnies"!!) someone suggested that the M15 requires to have a 2dB attenuator fitted? Now given my general ignorance/"wallieness" it didnt dawn on me that 2dB may be significant? The fact you mention 1dB in your post made me think it probably is!! LoL. On the klimax x over there are no adjustments for the midrange.
Would the fitting of such an attenuator be of use, and if so where do I get one (online I only seem to find 5 and 10dB??) and how is such an item fitted?

Im fast approacing 70, and the keltiks are going nowhere, so a bit of modding would be ok. Even if something goes wrong finding a replacement pair wouldnt be too difficult - they dont seem to attract much interest these days.

The reason I mentioned DIY above, was that - given I think there is enough power on tap - I could build another "midrange box" the same size width, depth/volume as the existing separate volume within the speaker and stand it on top??!! Connect in parallel????, and share the output. Building a "box" would be about the limit of my diy skills - I could stretch to some "roll over" edges! I read some of the threads on here with the real woodworkers with great envy/admiration.

"Steve, just turn it down a bit" - Naaaah.
 
Sounds like replacing the M15 with ER15 could get you the result you're after. They are not too expensive the last time I looked. As for building another mid box to put atop the Keltiks, that is not a good idea. You will truly screw up the dispersion of sound, and possibly suffer integration problems.
 
The original keltiks did not have that seas driver installed so the don't sound like keltiks already.

Rgds
Stuart
 
Stuart, yep I changed to the seas unit about 3/4 years ago - and noticeably a better sound at the time. Indeed, if it wasnt for the present slightly annoying issue, Id be more than happy to do nothing!
As James noted above the ER15 isnt overly costly so in the next few weeks Ill get round to giving it a try.

Cheers
Steve
 
poppop said:
Guys

System, which Ive had for a number of years, is Linn Keltiks with klimax crossovers, and 8 avondale power amps (200/220 boards)
Midrange is: Seas M15CH002 E0043-06S - Excel Series (crossover points: Bass to mid 118Hz, mid to treble 2400Hz)

Room size is c. 9m x 5m. and believe it or not I love the sound!

However, Im going through a youth revival and listening to a lot of Budgie. The problem is that on tracks like Breadfan, Infor the Kill, Parents and Black Velvet Stallion the midrange cone is slightly unhappy, having a tendency to almost meet me half way up the room!! "Er indoors" suggests turning it down but wheres the fun in that!

I dont have a clue about "parameters" and all the various specs, but Im ok with a bit of DIY.

Any suggestions for an alternative midrange that can cope with a bit more welly!!?

Thanks
Steve
Click to expand...

I’m using a Scanspeak 5” bass/mid with the same crossover frequency. Your driver is specified as 6mm pk-pk linear travel and 14 mm max.
I use a 2nd order (electrical) crossover and my drivers never move more than about 5mm pk-pk, even at ear ringing levels. (15W8434G00 xmax = 8mm).

Something seems to be amiss here!
 
S-man, thanks for input. Apologies, as above, my lack of knowledge in this area unfortunately means I can make no sensible comment.

Steve
 
Ah ok, I will try to put it in layman’s terms: I am surprised your mid drivers are moving so much. Is there any way you can get the crossover checked?

Are the bass units also moving a lot during your “Budgie” sessions?
 
Hi, the klimax crossovers(c.1999 vintage) are in fact being sent to Jez Arkless (former member of PF) this week for a service, in particular the power supply (SMPS?) This has been planned for sometime, and is not as a result of this issue.

The bass units dont seem to be having the same "stress" problem. Again, overall the sound is great - but "Budgie", Rammstein, and some progressive trance can generate that horrible "cracking" sound!!
Jez's answer is Ive got the wrong speakers, and to get some Kef Reference 4's. which to be honest Id never heard of!! LoL.

Its not a massive issue, as in the original post, if there was an alternative to the SEAS M15 that was more "robust" (excuse the non tech description) that would be great. For the cost, James's suggestion is one I will try in coming months.

Steve
 
Bariks are crossed over at 300hz, I’d be surprised if keltiks are crossed lower.

I’d make sure the mid enclosure is airtight and not allowing the bass to pollute the mid.

Exakt is likely a solution and certainly a huge step up from what you have.

You have mid adjustment, by increasing bass and treble by equal amounts, you reduce mid output by the same.
 
David, again cant add much Im afraid, other than reference previous posts re. the WAM discussion to which "sunbeamgls" (Im fairly sure) contributed the technical info. re crossover points.
Ive also passed the time where I can justify/afford to make significant changes/investment in Hi Fi. I genuinely like my system and thought it would be a relatively easy issue to "bung" something else in to overcome a relatively minor problem! BUT that is a reflection of my lack of knowledge - fairly clearly! LoL.

"I’d make sure the mid enclosure is airtight and not allowing the bass to pollute the mid." This I had never even considered. The mid chamber is an odd shape I think with a block of kustone(?) stuck to the side. The speakers will be c.25 years old, is it possible gaps/glue/sealer will have perished/deteriorated enough to cause this sort of problem?

Steve
 
Try pushing the bass unit in using equal pressure , it should spring back instantly and not suck. Also closely check the mid unit whilst you do this . There should be no movement.
 
poppop said:
... the midrange cone is slightly unhappy, having a tendency to almost meet me half way up the room!!
Click to expand...
Having just re-read your OP, I wonder if the active XO is doing its job correctly. If the mid-cone is moving that much, it would suggest that the low-pass section of the mid filter is not working (running wide open). Before you invest in a pair of ER15s, try running the Keltiks without the bass amps and see how low they go/sound.

Even when crossed that low, there should not be appreciable movement from the cone. One of my semi-active Ergo has the mid chiming in from 150Hz, and there is no visible movement from them.

The other possibility is a leaky mid-chamber, as David suggested. Running them without the bass amps going, and seeing whether they flap just as much, will narrow down one of the two scenarios.
 
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