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Your suggestion for 18" + 15" plans

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bob4 View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote bob4 Quote  Post ReplyReply Direct Link To This Post Posted: 25 March 2017 at 9:31pm
Originally posted by SouthwestCNC SouthwestCNC wrote:

Bee's 1850 hornresp parameters here:

https://freespeakerplans.com/forum/8-advanced-discussion/8687-horn-resp-for-beginners

And some others. Very helpful info there from bee.


wow, just plugged the numbers into hornresp for the 1850 horn. A single 1850 horn with L18/851 plays from 50 Hz upwards. But in a stack of 6 x 1850, hornresp the low corner drops to 46 Hz, with 145 dB max SPL output at full excursion (=xmax=9mm)!!! Provided of course the RCFs cone can take the abuse. Shocked 

To push it that hard you would obviously need to have a good limiter and HPF in place, because you would be within 2-3 dB of xmax (9mm) below 66 Hz

So on paper (or rather according to computer simulations) it should be able to play 8 - 10 dB louder than 6 x reflex Dead you will be trading some sub bass for higher sensitivity above 50 Hz
Of course you could limit the system to 140 dB, then you could run it flat down to 40 Hz.


But you might want to have these numbers confirmed by someone else though before you base any serious decisions on them. Im just sitting here entering numbers provided by others into some software Embarrassed

EDIT: sorry, did a rookie mistake on the input screen, had it on 1 pi for some reason, and hence my initial sensational claim..... EmbarrassedOuch
....but if you corner load, you get flat down to 40 Hz, I swear! LOL            


Edited by bob4 - 25 March 2017 at 9:44pm
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Post Options Post Options   Thanks (0) Thanks(0)   Quote SouthwestCNC Quote  Post ReplyReply Direct Link To This Post Posted: 25 March 2017 at 9:52pm
They were impressive horns in the time of the pd1850. How does it sim with 1850/2?
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Post Options Post Options   Thanks (0) Thanks(0)   Quote bob4 Quote  Post ReplyReply Direct Link To This Post Posted: 25 March 2017 at 10:07pm
Originally posted by SouthwestCNC SouthwestCNC wrote:

They were impressive horns in the time of the pd1850. How does it sim with 1850/2?

I dont know...... might be a bit offtopic though? I believe the Polish gentleman that started this discussion wants to get some advice on how to get the optimum from the loudspeaker components at his disposal? Embarrassed


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Post Options Post Options   Thanks (0) Thanks(0)   Quote SouthwestCNC Quote  Post ReplyReply Direct Link To This Post Posted: 25 March 2017 at 10:12pm
I wouldn't say so, he already has 2 1850 horns. The best advice may be sell the drivers and buy the correct ones. All said I have doubts about the 1850/2
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Post Options Post Options   Thanks (0) Thanks(0)   Quote matthies00 Quote  Post ReplyReply Direct Link To This Post Posted: 25 March 2017 at 10:14pm
not only, i am wide open for any discussion . Especially if i can get some infor for me tho ;)

so it seems like completin the horn 1850 isnt such bad idea?
Still can be completed by 15"? Maybe some kicks probided by 15" huh? on approx 140-200 Hz? OR it's pointles?


Edited by matthies00 - 25 March 2017 at 10:17pm
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Post Options Post Options   Thanks (0) Thanks(0)   Quote gen0me Quote  Post ReplyReply Direct Link To This Post Posted: 25 March 2017 at 10:35pm
Originally posted by bob4 bob4 wrote:

Originally posted by gen0me gen0me wrote:


This 18" eminence has a little better ts parameters

Hi,
just curious, how are the TSPs of the Eminence better? It has very low Fs(25 Hz), little bit lower Qs than RCF, but only marginally (0,3 mm) better xmax, and lower BL than RCF. 

Yes has weaker BL but has also lower Re which makes its motor stronger then rcf.

In italian standards ((vc-gap)/2 + 1/4 gap) this eminence has Xmax 7.175mm

If any of those speakers ts parameters are true is a totally different thing ofc.
Anyway its strange that such a crapy rcf speaker would have 9mm XmaxConfused
Sorry for all the confusion but tbh you should measure those speakers ts first and then sim them.

Edit
I was wrong. Emi could work in 1850. Will go 1Hz lower than in 186LOL due to excursion.
1Pi, 80V¬800W



Edited by gen0me - 25 March 2017 at 10:53pm
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Post Options Post Options   Thanks (0) Thanks(0)   Quote bob4 Quote  Post ReplyReply Direct Link To This Post Posted: 25 March 2017 at 11:08pm
Originally posted by matthies0 matthies0 wrote:


Still can be completed by 15"? Maybe some kicks probided by 15" huh? on approx 140-200 Hz? OR it's pointles?

no, if you decide to go with 1850 you shouldnt need any separate kick bin, as far as I know

also note that your tops will go easily down to 120 Hz or so. But they will be completely outrun by a stack of six 1850 anyway!!


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Post Options Post Options   Thanks (0) Thanks(0)   Quote bob4 Quote  Post ReplyReply Direct Link To This Post Posted: 25 March 2017 at 11:25pm
Originally posted by gen0me gen0me wrote:



Yes has weaker BL but has also lower Re which makes its motor stronger then rcf.
 

what does Re have to do with motor strength? I thought BL was the direct measure of motor strength ?

Originally posted by gen0me gen0me wrote:


Anyway its strange that such a crapy rcf speaker would have 9mm XmaxConfused
 

Weird, I was always under the impression that RCF is a more "Pro" company with higher end products than Eminence, for example the famous L15P200AK? Stern Smile



Originally posted by gen0me gen0me wrote:


Edit
I was wrong. Emi could work in 1850. Will go 1Hz lower than in 186LOL due to excursion.
1Pi, 80V¬800W


little bit optimistic with the 1 pi maybe? I did the same mistake as well though.... Confused

maybe matthies can elaborate which driver worked better in the 1850 in his opinion, the omega 18 or the RCF L18-851?

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Post Options Post Options   Thanks (0) Thanks(0)   Quote SouthwestCNC Quote  Post ReplyReply Direct Link To This Post Posted: 25 March 2017 at 11:34pm
You need the original pd1850 sim as a reference
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Post Options Post Options   Thanks (0) Thanks(0)   Quote bob4 Quote  Post ReplyReply Direct Link To This Post Posted: 25 March 2017 at 11:40pm
Originally posted by SouthwestCNC SouthwestCNC wrote:

You need the original pd1850 sim as a reference

good call.... but I cant be arsed at this hour anymore though OuchOuch
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Post Options Post Options   Thanks (0) Thanks(0)   Quote gen0me Quote  Post ReplyReply Direct Link To This Post Posted: 26 March 2017 at 12:17am
1850 sim is from https://freespeakerplans.com/forum/8-advanced-discussion/8687-horn-resp-for-beginners
186 from some another site.

Cant simulate 186 from there something is wrong with this 186 front chamber. Unfortunately in my 186 input data is the same mistake. Dont look at it!

Ok so here goes 1850 in 2Pi

71Hz 6.8mm on the mountain


Yes RCF is much more pro company, but its cheap speaker so it may vary a lot from its published parameters.
Motor force depends on Re and BL



Florentz=BxI=BlxI/l
IRe=U
P/I=U
P/I=IRe
I^2=P/Re
Florentz= Bl I/l=Bl P^1/2 / Re^1/2 l
l is length of conductor inside gap. It will be function of gap height vc height and conductor material resistance. Its good start for xmax wonderings. Or you can look at it as its fixed to gap height and vc diameter. Power is fixed.
It helps comparing different speakers motor strengths.

Edit
Just thinking about this 186 simulation. Could be simulated this way. More or less accurate. Its strange though someone treated first part of the horn as volume instead of making offset driver.
This 1850 is also simulated as Nd instead of OD.

Edited by gen0me - 26 March 2017 at 10:49am
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Post Options Post Options   Thanks (0) Thanks(0)   Quote matthies00 Quote  Post ReplyReply Direct Link To This Post Posted: 26 March 2017 at 11:42am
shit guys, your knowledge is freightening me :) and big respect.

I am not any pro, neither Hi-fi maniac, but for me Eminence and RCF did sound same way in the horn cub. I can't be sure about frequencies, since i haven't any measurement devices, and additionally we tested those on our old Cross RH Sound CX223.
Why i asked about horn, is because there was a bargain to purchase some horn looked cubs. Guy said it's build like Pol Audio T118. For me looks very similar to Horn construction, but i am not an expert.
Secondly, it was really bargain for cost less than 50€ / pc... but they are sold already :(

We are not in a rush, we can slowly consider what is right, and what is wrong.
I remind the idea, that for me it was just a pity do not use the 15's. Furthermore selling them will be i think also silly prices :)

Originally posted by bob4 bob4 wrote:

I'm no expert by any means, but that thin and long port looks wrong.

That i know already. Friend of mine told me this, and this is also a reason why we are considering the rebuild.
Originally posted by bob4 bob4 wrote:

Have you ever heard some kind of blowing/farting noises from these boxes at high level?

Yes indeed, the construction seems not solid enough for such power imo.
Originally posted by bob4 bob4 wrote:

You would definitely need to build some new cabs if you decide to do reflex, and make sure they are tuned appropriately. Other people on this forum can help you figure out the tuning and actual build plan. I don't think you can modify the old ones. Shame though if they are built from good 18mm ply...
That's why i am here :)



Edited by matthies00 - 26 March 2017 at 11:50am
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