Crossover for different impedance drivers

[sreten]

Hi,

Crossover calculators are always wrong as they don't
include compensation for the baffle step, even if you zobel.

Take a look at : Zaph|Audio - ZA-SR71

rgds, sreten.

Also look at https://sites.google.com/site/undefinition/diy/amiga
The cabinet proportions are nicked from you know who.

 

[dragonweed]

Basically the Staff is a "redesign" of the Mite, in a floorstanding version, using a bass tuning yielding the deepest F-3 point from the given woofer. X-over is almost the same, but due to the somewhat higher efficiency, the tweeter resistor is a bit less. Make the X-over on a test panel, placed on the top of the box, so you can easily change the values, and expriment until you get the best sound for your taste and system. Actually this is how I did most of my design work.... Microtuning is essential, sometimes tenth of ohms, and 0.1 uf changes in the values can make or break your day. Most of these speakers were designed using a Roksan Xerxes t'table , Dynavector Karat 23 Ruby cartridge, Artemiz tonearm, a self designed tube preamp, and Roksan ROK S-1 power amp (one of my all-time favourite). Your system choice might call for slightly different values tough..... Good luck, if you need more help, send me PM.

 

[Inductor]

dragonweed,
Do you mind I ask you where can I read more info (in book or "net" form) on the QM3 alignments, you mention on post #17. Can read English, French, Italian, Spanish, Portuguese. I will give a second read at your posts, they are interesting. Regards.

 

[sreten]

Speaker design software are a good starting point, but usually
have limited use when it comes to real-world drivers.

Hi,

Not true at all as soon as you ignore the suggested alignments
and make up your own bass alignments, which you can easily.

rgds, sreten.

 

[AllenB]

Crossover calculators are always wrong as they don't
include compensation for the baffle step, even if you zobel.

Baffle compensation cannot correct for the baffle either though. Even partial compensation won't correct it. It is an in depth subject.

 

[dragonweed]

Here is the article on the QM3 alignment. I think it is the "secret weapon" of reflex enclosure design, because it gives you almost limitless possibilities in choosing a box size and tuning for a given driver, with minimal low frequency ripple.

 

[Inductor]

Here is the article on the QM3 alignment. I think it is the "secret weapon" of reflex enclosure design, because it gives you almost limitless possibilities in choosing a box size and tuning for a given driver, with minimal low frequency ripple.

Hi, and thanks.
Is that the ""Résonateur ELIPSON""?!
Regards.

 

[portreathbeach]

I've been trying to get hold of some of the Tonsil drivers, but the couple of Polish companies who sell them haven't got back to me. Anyway, I also heard that Tonsil went bankrupt! is this true, and if so, what other drivers have very near characteristics as the drivers mentioned earlier in this post.

Or does anybody know where I can buy the Tonsil drivers from and ship to the UK?

 

[Inductor]

Tonsil GDN 13/40/2 8 ohm

portreathbeach,
I did a search and it seems that you are lucky, there are a few possibilities, more than you might expect.

1. Peerless 830860 HDS 134 PPB
http://www.tymphany.com/files/HDS-P830860 Rev1_0_0.pdf
Peerless 830860 HDS 134 PPB MidWoofer Speaker
The Madisound Speaker Store
Peerless 830860 5-1/4" PPB Cone HDS Woofer 264-1080
830860 - Peerless HDS-134PPB PPB diaphragm, 26 mm coil, AL - Europe Audio
http://www.diyaudio.com/forums/mult...60-vifa-xt-25tg-30-04-low-volume-tweeter.html
Peerless HDS PPB 830860

2. Audax HM130Z12
Haut-parleur grave médium Audax HM130Z12
Audax HM130Z12 (8Ohm)

3. Monacor SPH-5M
MONACOR INTERNATIONAL : New products
Monacor SPH-5M

4. Wavecor WF152BD04
WF152BD03_04
Wavecor WF152BD04 - Lautsprecher-Berlin
WAVECOR WF152BD04, 13cm bass/midrange driver, paper cone - Price per piece

5... I would consider many others variants, give a look, some might also be available in the UK.
Audax HP130Z0
http://www.audax.com/archives/hp130z0.pdf
HP130Z0 - RumoH - Caps, coils and speakers

 

[dragonweed]

You should also consider the SB Acoustics 15 series midwoofers, which are excellent performers in a cca.1/3rd cu.ft. vented box. Falcon Acoustics used to sell them at reasonable prices. SB Acoustics :: MIDWOOFERS

 

[sreten]

Here is the article on the QM3 alignment. I think it is the "secret weapon" of
reflex enclosure design, because it gives you almost limitless possibilities in
choosing a box size and tuning for a given driver, with minimal low frequency
ripple.

Hi,


There is nothing in that article that suggests stuff that is not already
known. Picking a peak ripple of 0.25dB just gives a set of very
arbitrary so called "QM4" alignments that I don't agree with at all.
Just an obscure criteria yielding a set of (poor IMO) alignments.

The "secret weapon" is knowing what you are actually doing.

rgds, sreten.

Here "quasi-monotonic" is a joke in terms of transient effects.
My criteria for vented is monotonic with an optimised low point,
which occurs depending on the drivers between -6 and -10 dB.

 

[dragonweed]

Without wanting to argue the wiewpoints of Sreten..... in speaker design there are so many factors and variables are present that CANNOT be modelled, that even his opinion cannot hold more water than any others. While it is true that vented alignments were thoroughly and deeply analized by real big names in acoustics, I personally believe -with my 25 years experience in the field- that there are still uncharted areas which need to be investigated. I worked for 10 years as a designer for Totem, and no one ever complained about the bass response of their models, in fact if there was anything most reviewers and customers were raving about, is their low end extension for the size of the boxes. No, i am not saying that they are perfect speakers, but musically they are very smart compromises within their limitations of size and price range. The reason I am telling you this, because almost all of them were designed with the QM3 alignment, of course with lots of trial and error procedure. So there is no reason just plainly refuse a theory because one has not enough knowledge about the subject.....

 

[portreathbeach]

One last question..... In the crossover in post 8, the tweeter used is an XT25 (4ohm). If an 8 ohm tweeter was used, would the cap (4u7) and inductor (0.3m) values have to be changed?

 

[sreten]

So there is no reason just plainly refuse a theory because
one has not enough knowledge about the subject.....

Hi,

Well I like being patronised ... The article is about QM4 not QM3.

I not refusing any theory, far from it, just that QM4 is simply
an arbitrary criteria yielding a set of arbitrary curves, that is it.
The article pretty much admits that, read carefully.

There is not much theory in that article, just loads of empirically
derived tedious tables, you can bypass with a decent simulator.

I don't have to agree with criteria for QM4 and I don't. Trying
to make out that is ignorance and refusal on my part is just
showing how much you really understand about the subject.

QM4 isn't a secret weapon. There are other good alignments,
with different (and IMO) better real compromises. YMMV.

rgds, sreten.

 

[dragonweed]

One last question..... In the crossover in post 8, the tweeter used is an XT25 (4ohm). If an 8 ohm tweeter was used, would the cap (4u7) and inductor (0.3m) values have to be changed?

The XT25 Vifa is a good tweeter, but extremely difficult to handle due to its low (560 Hz) Fs, and undamped (no ferrofluid) resonance peak. You better find an alternative like the DX25 TG-09-04 which is even better, but still inexpensive and much easier to work with. The values shown an post#8 are for the XT, but something close to it should work with the DX25 too.

 

[ProfGriff]

Totem crossover values

Hi There;

Sorry to raise a thread from the dead, but I'm in the process of swapping a pair of 8 ohm drivers in to a 4 ohm pair of Totem Mites. I have the crossover out, and it is a simple 1st order with a series coil (what looks like a Solen hepta-litz 16 ga) and a series cap (actually 3 in parallel for a total of 2.63uF) and resistor (can't read the value) on the tweeter. (i.e. this is NOT the same as in post #8, which is second order.) Also Totem spec's the x-over at 3.2 kHz, not 2.5.
One of the original 4 ohm woofers in my Mites is blown (after lending them to a friend no less) and rather than paying Totem $150 for a replacement one, I picked up a pair of tonsil woofers for 20 Euro online. These however are the 8 ohm version. I'm planning to use the "totems" with my restored Harmon Kardon A300 tube integrated as my office system, so 8 ohms is a good thing, since the A300 only has 8 and 16 ohm taps.
I realize they will not be the same speaker as the 4 ohm version, but with a little tweaking, I'm sure they'll work quite nicely.
My nest step is to take the x-over apart and measure the value of the woofer inductor, and calculate for the 8 ohm driver as best I can.

I'll try to keep y'all posted.

Griff

 

[BlueWizard]

Figure out what the rated impedance is on your drivers, or figure out the impedance at the crossover frequency.

Then use this calculator to determine the correct values.

Crossover Design Chart and Inductance vs. Frequency Calculator(Low-pass)

Find the nearest value to the calculations, or create a close value using series and parallel combinations.

At the bottom of the webpage is a calculator to make impedance controlled L-Pads (attenuators) should you feel the need for them.

Also the drivers you bought, you have to make sure the respond high enough to reach the functional range of the tweeter.

It doesn't matter what combination of driver impedance you have. If the woofer are 8 ohm or 4 ohms, just plug that value into the calculator. If the tweeter are 4 ohm or 8 ohms, doesn't matter, just plug it in and run the calculation.

Picking drivers is not as simple as I've got of 5" woofer, I'll just replace it with another 5" woofer. What is important is the high frequency response of the woofer, and the low frequency response of the tweeter, and making sure they can be aligned an an effective way.

Depending on how bad the Totum speaker was damage, it is possible to repair them. Typically for a pretty reasonable cost. The cone/voice_coil can be replaced. If surrounds are torn, then can be replaced.

Steve/bluewizard

 

[ProfGriff]

Thanks Blue Wizard, that's pretty much was my plan, but thanks for the link to the x-over calc. Keep in mind that the drivers I'm using are the exact same Tonsil driver that Totem uses, just the 8 ohm version. Bass tuning will be a little different, but as long as I use an inductor that's correct for the 8 ohm driver, they should be pretty much identical in the mids, which the Mites seem to excel at.


Griff