Fullrange Bipole MLTL speaker build

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“Hans: An eye for an eye leaves the whole world blind, I believe that wholeheartedly.
Billy: No it doesn't. There'll be one guy left with one eye. Hows the last blind guy gonna take out the eye of the last guy left, who's still got one eye! All that guy has to do is run away and hide behind a bush. Gandhi was wrong, it's just that nobody's got the balls to come right out and say it.”

Before someone takes out my eyes, I want to build a speaker so when the eyes are gone, I will have something to listen to instead of chasing the guy behind the bush blindly.

My first post here. So, not sure if this is the right place for this question.

I wish to build a bipole mltl speaker using full range speakers.

Late last year, I came across few DIY speaker designs and I was impressed with it. Furthermore, I am also impressed by the design of Apple Homepod and Sonos Sub desgin. So, I went ahead and build one small bipole speaker using cheapest that I could find locally, Dayton PC105 4ohms (PC105-4 4" Full-Range Poly Cone Driver - Dayton Audio) driver, two of them in one box mounted back to back. Initially, I went with sealed cabinet but than ended up drilling a large hole and put a bass port, and I was impressed with it. Bass went lower than what the specs said and what I expected. It is nice and punchy and clean. No lingering boominess. Well this was speaker made by what was available, no measurements or calculations were used to design the cabinet, just went to hardware store and asked them to cut a long plank in 5 equal parts for 4 walls and last part cut in half for top and bottom. Anyway, it was a good outcome. This leads me to building a proper calculated speaker cabinet with better drivers but 4 of them in one cabinet.

So, what I am looking to build is...

A bipole speaker with 4 drivers 2 in the front and 2 in the back in MLTL cabinet for better bass.
The reason I went for fullrange is to avoid any crossover designs as I am just getting into DIY and want to reduce any complications. I would prefer to use 4 small drivers (3" or 4" inch) instead of mid woofer and big woofer for bass extensions.

Any suggestions on drivers to use. Any suggestion on speaker cabinet designs and cabinet measurement calculations and etc. What about the power requirement, I assume using 4 speakers in one cabinet will require more power.

Appreciate your help.
 
frugal-phile™
Joined 2001
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I certainly have my favourite drivers and have given much thot to use of multiple drivers in ML-TL.

We were early proponenets of bipoles. They do have an issue with bipole dip, and when possible we moved to putting the 2nd driver on the top. Also using. abipole for bass, with the drivers facing sideways. To avoid combin gyou will need to have a filter on some of the drivers. Upward, sideways firing drivers tend to have less issues, back firing driver needs the filter if you find the bipole dip annoying.

I would start by arranging the drivers with 1 on each side, or 1 on each side, 1 on top and one on the front. This really needs an end-loaded ML-TL — The large size microTower, or a Pensil derivitive would work. (Pensil’s here, not all listed yet). One could take a microTower and build 2 pair per side and play with facing all sides ot just fore & aft by flipping one upside down on top of other. The distant termini would also load the room more evenly at vent frequencies. The Pensil could be adapted to a square cross-section to accomplish the same thing.

How much bass do you want? What size room? Size restrictions? Associated Kit? Tastes?

dave
 
That is a neat idea. Didn't think of mounting speakers on top and sides. Is there a link to that microtower you referred to?
How much bass do you want? What size room? Size restrictions? Associated Kit? Tastes?

dave

Bass somewhere 40hz to 30hz would be good. But given the small size it may not be possible.

As for the size I am open to idea, obviously not crazy big size.

I have Sansui AU-217mk ii amp with 40 watts per channel and planning to get higher amp but in same brand and make.
 

Funny you mentioned this. Your post was the one that inspired me to build my first set. Really great work.

Given that post was old, I wasn't sure if you were still around. I also couldn't find the drivers you used in that speaker so I ended up using 4 inch Dayton speaker for the initial build. Can I ask how was the bass on that speaker.

Here is the one I build. As I have mentioned, no measurements or calculations were used, I just built it with available wood and was impressed so much so that I stopped listening to my Q Acoustics 3020 bookshelf speaker. Oh! also I only built one for test and currently listening in Mono.

Your design is exactly how I want to build mine, but with transmission line port. Reading that post, I saw lot of talks went into to determine the size of the cabinet and port tuning.
 

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Founder of XSA-Labs
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Me still around? :)
I designed it but did not build it. I heard from the builder that the bass was great - people would ask where the sub woofer was hiding. The bipole eliminates the 6dB loss from baffle step falloff.

The design had a TL port - just a constricted (or so-called mass loaded) type.

I have basic Akabak script that can calculate it if you have a favorite driver in mind.
 
frugal-phile™
Joined 2001
Paid Member
That is a neat idea. Didn't think of mounting speakers on top and sides. Is there a link to that microtower you referred to?

Yes, in my last post.

Bass somewhere 40hz to 30hz would be good. But given the small size it may not be possible.

That is doable, you will need something like Alpair 10/11 (which have Pensils)

I have Sansui AU-217mk ii amp with 40 watts per channel and planning to get higher amp but in same brand and make.

You are unikely to need more power, but these days you can get better. I was never a big Sansui fan.

dave
 
frugal-phile™
Joined 2001
Paid Member
Me still around? :)
I designed it but did not build it. I heard from the builder that the bass was great - people would ask where the sub woofer was hiding. The bipole eliminates the 6dB loss from baffle step falloff.

Like the FH Lite that shows the ability to do a good job of the 1st harmonic, the 881 just cannot go much below 100 Hz.

dave
 
Me still around? :)
I designed it but did not build it. I heard from the builder that the bass was great - people would ask where the sub woofer was hiding. The bipole eliminates the 6dB loss from baffle step falloff.

The design had a TL port - just a constricted (or so-called mass loaded) type.

I have basic Akabak script that can calculate it if you have a favorite driver in mind.

I don't really have any specific speaker in mind, but was looking to do it with 4 inch driver. I could go with either of these two but open for suggestion, 1). Tang Band W5-1611SAF 5" Full Range Speaker or 2). Tang Band W4-2142 4" Paper Cone Full Range Driver 8 Ohm or 3). 5" Tang Band W5-1611SAF 5" Full Range Speaker.

Yes, I know that you had given ryani the measurements for the cabinets and port tuning. Thought you might have had a chance to listen to it, from the post I couldn't tell that you did.

I really liked that design and would be happy to go with given the right measurements.
 
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Is that the vent out the top?

dave

Oh yes, that is the port up top. :D

Initially, I had no plan and no right tools to do the build. You will see I used the screws to secure the cabinet, no wooden glue, but I did have silicone seal laying around and used that to make it secure and airtight. By the time I decided to drill a hole for port, it was too late to take it apart and the bottom was filled with poly fill so instead of risking the poly fill to leak out from port at bottom or sides, I decided to port it up top. This was just a try anyway, I didn't care for looks.

As for the port tube, I had some cylinder cardboard packaging around for some papers, so I drilled the hole to that size and stick that in and put silicone seal around to secure it.
 
I don't really have any specific speaker in mind, but was looking to do it with 4 inch driver. I could go with either of these two but open for suggestion, 1). Tang Band W5-1611SAF 5" Full Range Speaker or 2). Tang Band W4-2142 4" Paper Cone Full Range Driver 8 Ohm or 3). 5" Tang Band W5-1611SAF 5" Full Range Speaker.

Yes, I know that you had given ryani the measurements for the cabinets and port tuning. Thought you might have had a chance to listen to it, from the post I couldn't tell that you did.

I really liked that design and would be happy to go with given the right measurements.

1 and 3 are the same driver! ;)

I am playing with the W5-1611saf in a MLTL right now, and it beams quite low. It starts dropping at 3kHz, then like a brick at 8kHz.
That driver needs a tweeter. Easy enough adding one with a simple 2.2 or 3.3 uf cap on it. No fancy Xao.

It's not the cleanest nor warmest sounded driver. If I were to do it again, I'd stick with a 4" like the w4-1052sd, which needs a small notch then sounds wonderful.
 
1 and 3 are the same driver! ;)

I am playing with the W5-1611saf in a MLTL right now, and it beams quite low. It starts dropping at 3kHz, then like a brick at 8kHz.
That driver needs a tweeter. Easy enough adding one with a simple 2.2 or 3.3 uf cap on it. No fancy Xao.

It's not the cleanest nor warmest sounded driver. If I were to do it again, I'd stick with a 4" like the w4-1052sd, which needs a small notch then sounds wonderful.


Oops!! Made a mistake in tabs and copied the wrong URL of the drivers.

Here is the correct list of drivers I had in mind.
1). Tang Band W4-1052SD 4" Driver 4 Ohm
2). Tang Band W4-2142 4" Paper Cone Full Range Driver 8 Ohm
3). Tang Band W5-1611SAF 5" Full Range Speaker

After your comment about the w5-1611saf, I might have to look for another one. And the 4" w4-1052sd driver you mentioned, was my first choice but copied the wrong URL :).

I figured 4 4" drivers would be enough for good bass and possibly be able to avoid adding tweeter, but if need be, adding tweeter would be easier than building a 3 way with big woofer.
 
That, we agree on the 1611.

bluehalk, the w4-1052sd would not need a tweeter (unless you have the ears of a teenager!).

What it does need is to tame some stored energy between 5 and 8kHz... then it sounds wonderful. Easy enough to add a small notch after you built the 4-driver version and measured it to see exactly where to put the notch in your case.
 
That, we agree on the 1611.

bluehalk, the w4-1052sd would not need a tweeter (unless you have the ears of a teenager!).

What it does need is to tame some stored energy between 5 and 8kHz... then it sounds wonderful. Easy enough to add a small notch after you built the 4-driver version and measured it to see exactly where to put the notch in your case.

Forgive my ignorance, but what do you mean by "notch"? like a crossover or something?
 
frugal-phile™
Joined 2001
Paid Member
A notch is an XO filter that depresses a portion of the frequency usually to help hide a resonance peak. The FR will be flattened, but the resonance is still there, and now you have reactive components between the amp & speaker, which can screw up the flattness of the impedance. Something i like to avoid.

dave
 
Given the current COVID19 pandemic, I highly doubt I would be able to source the previously mentioned drivers from Parts-express. I have ordered a tube pre-amp from amazon about a week ago and it still hasn't been shipped, and given all the lockdowns happening, I am not keeping high hopes.

So, I think it would be better to work with the drivers that are locally available here in Australia. Unfortunately, the choices are very limited.

1). PC105-4 4" Full-Range Poly Cone Driver - Dayton Audio @ AUD $24.40
2). PC83-8 3" Full-Range Poly Cone Driver - Dayton Audio @ AUD $21.70
3). DSA90-8 3" Designer Series Aluminum Cone Full-Range Driver 8 Ohm - Dayton Audio @ AUD $36.50
4). PS95-8 3-1/2" Point Source Full-Range Driver 8 Ohm - Dayton Audio @ AUD $34.50
5). RS100-8 4" Reference Full-Range Driver 8 Ohm - Dayton Audio @ AUD $59.00
6). https://www.wagneronline.com.au/sb-...dio-speakers-pa/sb10pgc21-4-89895/1002163/pd/ @ AUD $24.50


I already have two drivers of option 1 from my trial build which I intentionally got the 4ohms version to yield 8ohms output when parallel wired. I could get further two more for 4 driver build for one speaker and save money but would end up with 4 ohms load when all 4 are wired.

Is anyone able to recommend a driver from above list. Please note, if needed I can add a single inexpensive tweeter for HF.
 
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