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what should be the distance between woofer & tweeter?? (in a diy two way BS)

Wharfedale EVO 4.1 4.2 Speakers

Naveenbnc

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Hello All,
How do we determine the distance between the woofer and tweeter in a 2way BS?
I mean, how close or how far away they can be placed?
I read somewhere that it depends on the crossover, but not very sure.
Any suggestions please ....

Thanks in advance,
Naveen
 

yogibear

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CTC rule applies between tweeter and midrange. Single / or half / or quarter wavelength of the XO frequency is a debatable issue from practical perspective. Even single wavelength demands a smaller midrange if you wish to XO at 3000 Hz, the ideal crossing point.

If it’s a 2 way I would say keep closer as possible. If the tweeter is sealed back then life is simpler as the woofer gets all the volume to itself.

Though the acoustic rules are often not followed wrt spacing. Classic examples are many.... Altec, JBL etc.

There is no substitute to experience and experimenting in Audio DIY.

CTC is crucial when you design an MTM or Line Array. (CTC refers to centre to centre distance between mid and tweeter)

Just my little understanding. More experienced DIYers would say it better....
 
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Naveenbnc

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thank you Yogibear ...

For 3000Hz, the wavelength is 11.4cm
Im using an 8" woofer.
So even if I place the woofer and tweeter touching each other, the CTC will be around 13.5cm (more than 1 wavelength)

So as you said, we just have to place as close as possible. (if my understanding is correct)
 

yogibear

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thank you Yogibear ...

For 3000Hz, the wavelength is 11.4cm
Im using an 8" woofer.
So even if I place the woofer and tweeter touching each other, the CTC will be around 13.5cm (more than 1 wavelength)

So as you said, we just have to place as close as possible. (if my understanding is correct)

In a 2 way, a lot depends on the specs of the tweeter and the woofer itself.

It’s very important that you have the correct TSP of both. For example if you cross the tweeter at its Fs then you must use a crossover network with steeper slope like 24dB / octave so as not to damage the tweeter. The woofer on the other hand must comfortably manage the crossover point. Other things to consider is both should have similar impedance and similar sensitivities.

See the impedance vs freq graph of the woofer as well. It should be as linear as possible. Don’t try to aim too low on the woofer part. If a BS has finely mated tweeter and woofer and they do just sing along well till 50hz then it’s just great and better than aiming to make it sing a lower at 40 hz.

You will want to complement it by subs later.

I would personally decide the crossover frequency in a 2 way depending on specs of both drivers and look for a sealed back tweeter and place it as closer as possible but in a thick front baffle and even try a truncated plate tweeter.

I would play with different baffles wrt placement.

Again a couple of more experiments if your BS is ported and not sealed.
 

Kannan

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@yogibear Ji, even at 24db slope it is extremely unsafe to cross tweeters at the f/s point.
It is always safer to be an octave or above.

Regarding speaker positioning, keeping them close and in perfect vertical axis is the safest bet.
Second important thing is to always flush mount drivers and work out a physical time alignment by having the tweeters a little recessed compared to the woofer.

Whatever you do, the biggest challenge is going to be the crossover. That is what decides on the performance and the hardest to configure.

Does need in-depth knowledge of the speaker parameters, designing softwares and hardware tools.

It will be one long and interesting learning curve.

If you get a grip of this, sky is the limit and you can build seriously good speakers at an extremely affordable price.
 

Naveenbnc

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the biggest challenge is going to be the crossover. That is what decides on the performance and the hardest to configure.
The crossover design is in safe hands. Aniket is going to help me.
The only thing I may screwup is the enclosure design:D:D
I am learning now. After getting some grip on the enclosure design, I will learn crossovers.
 

yogibear

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Yes Kannan, though to be safe, I would always cross tweeter about 500 Hz above it’s Fs even at 24dB slope.

Naveen, not to dampen your spirits but if you are starting your DIY journey with a 2 way BS, and have already bought a midrange/woofer, then search for popular designs already published. Else you can look for popular BS DIY builds.

It’s a lot about drivers, enclosures and passive networks where all have to work together for a coherent design.

My attempts and experiments drew me to extended and full range drivers to make my life simpler and more musical and I nearly did away with crossovers. (At least so far...) Single point reproduction again came with its own benefits and unmatched imaging.

And open baffle was again huge relief as the whole cabinet making was done away with and I rather saved and invested on drivers and amps.

But everyone has his own learning curve and it’s a rewarding hobby..... Good Luck with your attempts.
 

Naveenbnc

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Yes Kannan, though to be safe, I would always cross tweeter about 500 Hz above it’s Fs even at 24dB slope.

Naveen, not to dampen your spirits but if you are starting your DIY journey with a 2 way BS, and have already bought a midrange/woofer, then search for popular designs already published. Else you can look for popular BS DIY builds.

It’s a lot about drivers, enclosures and passive networks where all have to work together for a coherent design.

My attempts and experiments drew me to extended and full range drivers to make my life simpler and more musical and I nearly did away with crossovers. (At least so far...) Single point reproduction again came with its own benefits and unmatched imaging.

And open baffle was again huge relief as the whole cabinet making was done away with and I rather saved and invested on drivers and amps.

But everyone has his own learning curve and it’s a rewarding hobby..... Good Luck with your attempts.
what you said is really true !!!
As I understand, all the soldiers exhausted with 2 way, 3way, and multi way designs seek refuge in fullrange eventually !!!:D:D
May be I will also end up there ....
Dr.Karthik recently made OB and he is very happy with it.

Coming to OB, is it suitable for HT?
I mean, can can we make Left, right and center with Full range Open baffle???
 

Kannan

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As I understand, all the soldiers exhausted with 2 way, 3way, and multi way designs seek refuge in fullrange eventually !!!:D:D
May be I will also end up there ....
Dr.Karthik recently made OB and he is very happy with it.

Coming to OB, is it suitable for HT?
I mean, can can we make Left, right and center with Full range Open baffle???

I am from the diametrically opposite pole. I started with mammoth full rangers, mostly old school and ended up with multiway active setups.
Will never revert back to full rangers.
I find modern drivers offer much more in the plate in terms of compactness, performance and efficiency.
 

Naveenbnc

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I am from the diametrically opposite pole. I started with mammoth full rangers, mostly old school and ended up with multiway active setups.
Will never revert back to full rangers.
I find modern drivers offer much more in the plate in terms of compactness, performance and efficiency.
Interesting :):)

If OB and Full range can do all the magic, why the heck the whole drama with multi way and enclosures ??

Your quote is the answer for this i guess.
Looks like Each has its own benefits !!!
 

yogibear

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There are modern drivers suited for OB as well though the choices are limited as the fight gets crucial looking for High Qts and low Fs in bass and top end sparkle in case of full range. Visit me, I will shock you with an OB made around with only modern drivers ! (97dB to 101 dB and 17k to 35hz in a 2 way)

What really bugs me in a multiway boxed speakers is loss of sensitivity and the driver character/signature being masked by passive components and the enclosure itself. I am a midrange guy and cannot compromise it in a setup.

Yes, you can make a HT OB and I do have all the drivers and tube amps in place to do a 5.2 except a good DSP with room correction and my current space is small for that.

If one delves into OB, so far my experience says, the mid-treble has to be driven by tube and high sensitivity drivers (>95 dB) is a must. Though I hope to finish building and testing a pure Class A amp with a tube first stage. Never played a pure Class A amp in my OBs and I hope to start with a hybrid soon.
 

Kannan

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@yogibear sirji you too should listen to my 2-way modded Infinity sprakes.
I love their signature off my Class A amp, but they sound pretty good with Class AB aswell.
The tweeters are the venerated polycell, just a step below the Emits.
The woofer is IMG.

I do a lot of editing work from home (mostly at night) so listen for long hours.
 

yogibear

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@yogibear sirji you too should listen to my 2-way modded Infinity sprakes.
I love their signature off my Class A amp, but they sound pretty good with Class AB aswell.
The tweeters are the venerated polycell, just a step below the Emits.
The woofer is IMG.

Sure, would love too....
 

yogibear

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An example of what could be termed as “ “Extreme” in CTC spacing:

3EC5E1C7-9E15-42F2-B4E0-BA125D45BAB7.jpeg

The tweeter is original Denmark made, double magnet 6 ohm Vifa and woofer is a 7” carbon woven cone made by Peerless, Denmark, both with truncated faceplate / frame.

But the drivers must not touch each other IMO.
 

yogibear

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Lovely looking drivers. Are they still in production?

Vifa can be found sometimes on eBay US but the midbass was OEM to some name brands and is harder to get. Midbass does have some amazing vocals and I plan to test this duo and the midbass with another very amazing horn tweeter ( I flicked 5 pairs when they were available) in my upcoming modular OB build.

Woofers very similar to the ones I have:

https://rover.ebay.com/rover/0/0/0?mpre=https://www.ebay.com/ulk/itm/332739008973

These are also marketed by scanspeak.

Tweeters:

https://rover.ebay.com/rover/0/0/0?mpre=https://www.ebay.com/ulk/itm/222710964042

Current production probably.
 
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Naveenbnc

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I'm not going to buy right now, but just asking....
If we place an order, they cost us only the dollar conversion price?? Or any additional charges like customers etc ??
 

Hari Iyer

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If I design a first order filter, the wave length at crossover frequency is the distance between the woofer and tweeters center. At higher orders this won't any way matter as there is a phase reversal.
 

yogibear

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I'm not going to buy right now, but just asking....
If we place an order, they cost us only the dollar conversion price?? Or any additional charges like customers etc ??

Freight and then customs duty at the total amount.
 
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