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New Mid-Top *in progress

Printed From: Speakerplans.com
Category: Plans
Forum Name: New Projects Forum
Forum Description: Forum for new speakerplans projects, in memory of Tony Wilkes, 1953 - 2014
URL: https://forum.speakerplans.com/forum_posts.asp?TID=1421
Printed Date: 17 April 2024 at 2:40am
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Topic: New Mid-Top *in progress
Posted By: staiper
Subject: New Mid-Top *in progress
Date Posted: 18 February 2005 at 4:41am

Hi,

At the moment this cabinet exist only on a paper.. Due to my other jobs and duties I will be able to make some prototypes not before 5th month. Every comment is welcome.

 




Replies:
Posted By: staiper
Date Posted: 18 February 2005 at 4:53am

uuupsss! Now I see I have started on wrong sub-forum.. this belongs to "New projects forum"

BTW there is higher resolution picture of project;

http://groups.msn.com/SpeakerBuildingpics/shoebox.msnw?action=ShowPhoto&PhotoID=44 - http://groups.msn.com/SpeakerBuildingpics/shoebox.msnw?actio n=ShowPhoto&PhotoID=44



Posted By: mobiele eenheid
Date Posted: 18 February 2005 at 5:29am

Well, it looks nice! A good beginning is half the way. Tho I'm more interested in sims, if available.

Do you think 10" will get you low enough to use above 18" BPH?

Cheers



Posted By: staiper
Date Posted: 18 February 2005 at 5:50am

Hi,

The mid horn lenght is 62cm which is one qarter wave of 138Hz. My bass cabinets (bandpass-hoorns) can reach to 160-200Hz range w/o problems so I think it will work fine.



Posted By: mobiele eenheid
Date Posted: 18 February 2005 at 7:44am

You're not gonna simulated or anything? Generally there is more to horns than just an 1/4 wavelength path.

Cheers



Posted By: Pinheiro
Date Posted: 18 February 2005 at 8:22am

Hi all

The Staiper is correct on my math at 15ºc the min xover for that horn is 137Hz

And one xover point for me whiad HD215 or HD15 can be set at +- 160Hz

Yours Vitor



Posted By: Tom Umney
Date Posted: 18 February 2005 at 9:03am

What drivers are used in that new design???

 



Posted By: young poon
Date Posted: 18 February 2005 at 9:33am

what if you ported rear chamber though the front of horn. Where it meet the front.

poon



-------------
young, gay, proud and into speakers


Posted By: Timber_MG
Date Posted: 18 February 2005 at 9:36am
You'd loose efficiency.


Posted By: young poon
Date Posted: 18 February 2005 at 10:07am

but if a port only takes as much as it gives and it is tuned to 60 Hz, why will it effect efficiency anyhwere else. Dosen't in a reflex box.

poon



-------------
young, gay, proud and into speakers


Posted By: Contour
Date Posted: 18 February 2005 at 10:58am

There is a large jump in crosssection area for the HF driver. Don't you think this will be a serious problem? I also think there is a lot of unused space in this design.

Best regards,

Walt



Posted By: norty303
Date Posted: 18 February 2005 at 10:59am
Yeah, but all that extra air makes it lighter.

-------------
My laser stuff: http://www.facebook.com/SubsonicSystems" rel="nofollow - Frikkin Lasers


Posted By: Contour
Date Posted: 18 February 2005 at 12:03pm

I don't see the advantage of this design above a unity concept. The loading on the cones may be more efficient but the overall sound will not be very good I think. HF horns are very sensitive to this kind of jumps in cross section area.

Best regards,

Walt



Posted By: Timber_MG
Date Posted: 18 February 2005 at 12:26pm
Except if the Mid drivers load over a slot. However the sudden change in flare-rate in the horn will cause a reflection or two, but nothing to worry about as this is quite common in PA-type horns.


Posted By: Contour
Date Posted: 18 February 2005 at 12:49pm

I am not talking about different flare rate. Please take a closer look at the design to see what I mean.

Best regards,

Walt



Posted By: freddyi
Date Posted: 18 February 2005 at 1:41pm
looks like theres a vertical diffraction slot from HF feeding the larger section - maybe I'm missing something on interpreting one or two views???

whats happenin' in the HF section transition Staiper?


Posted By: JD01
Date Posted: 18 February 2005 at 2:48pm

I guess this horn will give response to 1kHz, maybe 1,2kHz with some luck. But i don't think the HF driver will go that deep. And even if a driver is used that can do it, it won't be loaded properly enough to run down to 1,2kHz. And I guess the reflections in HF range won't be piece of cake. Gonna get nasty....

I'd take the design but position the HF on a usual horn frontmounted, so it gets coaxial....



Posted By: staiper
Date Posted: 18 February 2005 at 3:10pm
 

This is still “virtual” cabinet and at the moment I really can not prove its performance or sound quality.

 Yes this design maybe looks much unity-like (and I must confess that unity horn makes me to think about this design) but in unity horn design you must use relatively small midrange units (5-6inch) to fit them close enough to HF unit and midrange throat area is very-very small (and practically it is impossible to make them a bit larger due to very tight area and sensitive position- very close to HF throat).

In this design I can use larger units (lower cutoff, more power) and bit larger throats but preserve physical time alignment and near to coaxial output.

Due to “unused” space in cabinet it can be “fixed” a bit by making trapezoidal cabinet (I have this version in papers but it is not important at this stage). Cabinet is same dimension as my bass cabinets to make stacking more flexible (same approach used by HK, Dynacord.. etc..)

HF horn is basically diffraction slot which output is “mixed up” with midrange and then squeezed together into larger waveguide.

 

P.S.

 Optionally unused space can be filled up with helium gas and it makes stack of eight cabinets transportable on one hand!!



Posted By: freddyi
Date Posted: 18 February 2005 at 3:24pm
cool  - hope "mix" comes out good - will HF need 4th order highpass to protect? - (looks like ~350Hz 1/4 wave path for the HF diffraction section)


sometime - help me w. a K. - "if" can be worked out


Posted By: Timber_MG
Date Posted: 19 February 2005 at 5:50am
It's not the 1/4WL that matter as much as the size to get the HF driver loaded.


Posted By: freddyi
Date Posted: 19 February 2005 at 7:38am
is hornresp good for showing load for HF waveguide? - if so, like to see what it says for old "Smith" horn - without baffle, real hard to localize

(--how does one estimate parameters for a compression driver?)
  


Posted By: Timber_MG
Date Posted: 19 February 2005 at 7:50am
One doesn't. Compression driver and horn interaction is something where one cannot just whip out a model. (excep if it is FEA or similar) There is a lot more to it than just guessing a nice set of parameters if it has to really good. Fortunately there is always the conical variant (with different throats) which makes life a little easier.


Posted By: freddyi
Date Posted: 19 February 2005 at 7:59am
thanks Timber_MG - got feeling 'experience is useful

can a LCR trap like what is sometimes used on dome tweeeters at fc be applied to horn /driver ? - or does this not make much sense?


Posted By: djeddie
Date Posted: 20 February 2005 at 7:35am

I know someone has already said about the 'empty space' in the cab, but would it not make sense to make the cab trapezoid (?) in shape?, so that if you have 2 per side you can angle the mid-hi cabs to gain a wider dispersion.

(P.S. The 'edit' button is brilliant idea)



Posted By: young poon
Date Posted: 20 February 2005 at 8:12am

well I love it.

I feel so bad that you show your design on here and most people just try to rip it appart and find the bad in it.

Just do it and don't tell no one. If you did this around here you would be loved by everyone.

Don't you just love the smell of complacency in the morning.

poon



-------------
young, gay, proud and into speakers


Posted By: mobiele eenheid
Date Posted: 20 February 2005 at 8:24am

Quote I know someone has already said about the 'empty space' in the cab, but would it not make sense to make the cab trapezoid (?) in shape?, so that if you have 2 per side you can angle the mid-hi cabs to gain a wider dispersion.

Yes it would:

Quote Due to “unused” space in cabinet it can be “fixed” a bit by making trapezoidal cabinet (I have this version in papers but it is not important at this stage). Cabinet is same dimension as my bass cabinets to make stacking more flexible (same approach used by HK, Dynacord.. etc..)

Quote I feel so bad that you show your design on here and most people just try to rip it apart and find the bad in it.

Most times there is just a small line between ripping something apart and pointing out the weakpoints of a design.

It takes a matter of time to see who's doing what. Aren't you a little to quick in your judgments, or am I?

Cheers



Posted By: Timber_MG
Date Posted: 20 February 2005 at 9:00am
Young poon, taking that you are too stupid to guage what a well adapted post or avatar description on the squatjuice forum is, I suggest you stop trolling. If I post a design I am only too happy if people point out possible weaknesses (and this has thankfully always been the case) and I am sure Staiper is more than mature enough to gauge comments and make useful use of them. All engineering issues in general revolve around compromizes.


Posted By: mobiele eenheid
Date Posted: 20 February 2005 at 9:13am

Hmm that first sentence remindes me of Gandalf

 



Posted By: freddyi
Date Posted: 20 February 2005 at 11:18am
gentlemen - Staiper does cool stuff - as "diversion", critique this lovely 2-way cab bult by an internet buddy: http://home.earthlink.net/~buddhaboy2/X.jpg - http://home.earthlink.net/~buddhaboy2/X.jpg


Posted By: JD01
Date Posted: 20 February 2005 at 1:09pm

@ freddyi: Argh, Karlsson again.... :)  I guess this design has some mids missing (Well, not in theory, but...).

@ Young poon: Timber is right. Noone here is ripping the design apart. Everybody in here is HELPING staiper with their thoughts about the design. Nobody is perfect. What seems to be a really good idea to the one, might be a horrible idea to another.

As I said, I think the reflectioons will be 'evil' and the HF driver won't be loaded enough to reach the frequency where the 10"s will play good to. But I could be wrong. That's the thing about a forum, EXCHANGE!



Posted By: djeddie
Date Posted: 20 February 2005 at 2:10pm

Just a quick note for mobiele eenheid, I'm not trying to rip apart the idea of the cab and I'm not being negative. I was just giving my ideas to Staiper, I think the idea for the cab is excellent. Several times I've built something, whether it be a speaker cab or a mixer, and once the idea is presented someone will always say 'ah, shouldn't you have done this or that before finishing it'. So if Staiper has the original idea and takes on board what everyone has to offer or not, surely the end result would be better? So therefore I think you are being a little quick in your judgements, only a tiny little bit though!



Posted By: mobiele eenheid
Date Posted: 20 February 2005 at 4:31pm

Quote Just a quick note for mobiele eenheid
Hmmz...I am not sure if I am understanding what you say completely.

As I can read from your post it seems to me that you agree with what I say. But you're writing your post like you're offended or something.

So could you explain a little bit better what it is, that you're disagreeing with?

 

As I was saying there is a small difference between being negative about a design or pointing out possible weakpoints either in design or knowledge. It's just all about the persons intension. That's a little bit hard to see on the web. Especially if you don't know a person either face to face or on the web.

My guess is young poon doesn't know the people reacting well enough to know about their intensions. Because I believe most reactions look negative but are well ment.

My intension was interest in Staipers design and asking him in my own way how far his knowledge goes. This way it would be easy for me to see if he could benefit from my knowledge or not. To this point that's still unclear to me.

I know my designs would have benefit greatly from my knowledge as it is now. To bad that's exactly the way I got in the first place.

By the way: I've never mentioned you by my knowledge or actually judged anyone in a wrong way, so why your reaction?

Mvg Johan



Posted By: Timber_MG
Date Posted: 20 February 2005 at 4:39pm
Yup, actually (as has been seen in the unity, EAW and Renkus-Reinz products) this arrangement desirable for a number of reasons. The only concern is how the HF driver will interact with the mid-throat in this arrangement, but that one can never really know before not having litened to the box by oneself.


Posted By: young poon
Date Posted: 20 February 2005 at 7:00pm

*Timber*

still didn't answer my question. Why would addding a port lose effeiciency.

Take a sealed box with speaker in it. Add a horn to front of speaker. You now have a bandpass gain from fo to upper cutoff. Say fo is 140 Hz like in Staipers design.

Now take the horn off and port the box. fb of 60 Hz. Are you telling me that frequencies above 140 Hz are going to be quiter from the cone now there is a reflex port added. Yes, cone movemet will be reduced at and around fb and the port cannot add the same gain as the horn, but we are asking the port to reproduce a single frequency just over one octave below the cutoff of the horn. So if we now add the horn to the front of the speaker again why will 140 Hz to upper cutoff have lost effeiciency. If the port was working within the horns passband then yes it would have to match the horns gain, but this is not the case in this design.

Granted trasient response will not be as good, but try telling the above to Altec with their L-F series horns, model numbers 210, 211, 410 and 825.

Poon



-------------
young, gay, proud and into speakers


Posted By: Timber_MG
Date Posted: 21 February 2005 at 2:37am
Read up on elementary horn theory (esp. Leach, on the specification of ....). Keyword: reactance anulling and the basic functioning of a horn.


Posted By: staiper
Date Posted: 21 February 2005 at 7:17am
 Hi to everybody,

To make things clear.. Design is posted on forum to discus its bad or (eventually J ) good aspects.  I am do not finding myself offended by any comment. So.. as I say all comments are welcome (including negative ones) ;)

 This is just preliminary idea and I am planning to make first prototype like posted one then measure it and then play a bit with different HF flare extensions and center wedges and measure it again…

 For example;

 

 



Posted By: freddyi
Date Posted: 21 February 2005 at 11:03am
cool vanes - will be interesting to hear results- heres crude cardbaord wings added to small HF horn

http://home.earthlink.net/~buddhaboy2/LIP.jpg - http://home.earthlink.net/~buddhaboy2/LIP.jpg


Posted By: Pinheiro
Date Posted: 21 February 2005 at 2:16pm

Hi Staiper

My take on the project

look at this http://www.renkus-heinz.com/technologies/tech_pat_co.html - http://www.renkus-heinz.com/technologies/tech_pat_co.html  might do the job

my idea is to put on the centre the WL5 from Beyma and do some custom horn for mid (more then 90º)and the mid hi of speakerplans line array or one kick ass trapbox whiad HD15

keap the great job

Yours Vitor



Posted By: Timber_MG
Date Posted: 21 February 2005 at 2:21pm
Speakerplans has a line array design?  Whoa, where is Jesus Christ and dubsuction with that 'erbal remedy?

* we now return to your scheduled programming *


Posted By: Pinheiro
Date Posted: 21 February 2005 at 3:50pm

Hi

Speakerplans has a line array design?Not at this moment but whiad that 'erbal remedy  can start one ?

Line array it not that hard to plan (see Vertec ,Martin ....)

yours Vitor

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Posted By: Pinheiro
Date Posted: 21 February 2005 at 3:52pm

Hi

Watt is this ???

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???????



Posted By: JD01
Date Posted: 21 February 2005 at 6:23pm
Yeah, a LA is easy to plan, but hard to find really working speakers (so you can operate within the necessary physics). Even harder if you try to make your own transformer for the HF range (would be much easier to buy a BMS 4510 or the Alcons ribbon...).


Posted By: Pinheiro
Date Posted: 22 February 2005 at 6:06am

Hi

Some of the problem can be solved whid WL5 trasformer

the mid is very simple just look at http://www.linearraykits.com/design-acoustics.com/LA1246.htm - http://www.linearraykits.com/design-acoustics.com/LA1246.htm

yours "love this job "Vitor



Posted By: JD01
Date Posted: 22 February 2005 at 2:51pm

@ Pinheiro: Yeah, mids like that are indeed simple, but they don't work well (I mean the mids will work well, but HF will be affected by the mids cone motion). And the HF of those systems doesn't seem to have a transformer.... Their smaller system is a very stupid invention.... why use a 10" woofer AND a 10" midrange?

 



Posted By: JD01
Date Posted: 22 February 2005 at 2:54pm
Oh, tell me more about that WL5 thing.


Posted By: Pinheiro
Date Posted: 23 February 2005 at 5:44am

Hi

the plan for mid is to do one slot like in the vertec (vertec as two slots on mid and on the JBL model the distence is +-10cm and at 3khz is almost 1 wavelengh)

the info on the WL5 is in http://profesional.beyma.com/ENGLISH/producto.php - http://profesional.beyma.com/ENGLISH/producto.php  

 

yours hope it helps Vitor



Posted By: JD01
Date Posted: 23 February 2005 at 9:50am
3kHz is too high for LA mid range anyways. A decent driver like the BMS4510 or the Alcons ribbon can go down to at least 1,3kHz. With the right speakers you can get coherent coupling....


Posted By: JD01
Date Posted: 23 February 2005 at 9:52am

Oh, that WL5 looks like a clone of the BMS 4510....

 

We need an edit-button!



Posted By: Timber_MG
Date Posted: 23 February 2005 at 2:36pm
Und du brauchst brillen?


Posted By: JD01
Date Posted: 24 February 2005 at 1:08pm
Ich habe eine! But why's that? Because the WL5 is with 1,4" throat?


Posted By: Timber_MG
Date Posted: 25 February 2005 at 5:38am
Becasue if you look carefully at the bottom right of your post you'll see an Edit button. Sorry for being so rude.


Posted By: Pinheiro
Date Posted: 26 February 2005 at 2:04pm

Hi

i was looking at lab sub forun and some one post one plan "pk2115"

but looks like is mising but ok

the plan was one trap box whiad one Bms 4590 on DDS 60x and to 15" delta LF"?"

look very nice for one full range box

one diferent plan is some dual 12 horn and the 4590 whiad low x over  can do some good box to go whiad HD15 and kickass 3 way top

yours Vitor



Posted By: Timber_MG
Date Posted: 26 February 2005 at 2:18pm
@ Poon: I have re-read the thread and you do have a point. If the driver could reactance-anul (in a 140Hz mid-horn like your Porn Horn) with a large rear chamber (like what Bill Fitzmaurice suposedly does with his bass-cabs), then one could look at a hybrid like you suggested. However one would need a really weird (OEM) driver to have both the ability to funciton in a large rear chamber (ignoring resonances for one) and the strong motor/light cone to be any good at loading over a high bandwidth.

One could then look at loading the "port" closer to the throat of the horn and try and reduce its Q. Not something I' try on a mid-horn anytime soon, but one never knows.


Posted By: JD01
Date Posted: 02 March 2005 at 12:28pm

Hmmm, edit button. Great. When did that happen?

I didn't see it because in all other boards I visit it is near the quote button....

BTW I think you have spoken too much english. Glasses is singular in German: Brille.... :)

Venting the rear chamber of a midhorn often results in loss of max spl capability in the low mids.... I don't know numbers, but it's basically a fact...



Posted By: Timber_MG
Date Posted: 02 March 2005 at 1:47pm
Except if the diver paramers are such, that you can still reactance-anull. however I have my doubts whether such a driver exists.

@ JD01, fair enough. I am fairly fluent in three languages, so it is inevitable that something will get mixed up somewhere. Languages aren't exactly my forte.



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