How to choose correct Drivers for DIY speakers? need advice

[spirovious]

Hi friends,

I am very new to this section of forum.May there others too who may need to know the subject.I have been reading other sites & learnt that one should get correct driver combination to get good sound out.

Some of the facts that if someone need detailed sound(said to sound bright),he has to choose probably Aluminum Tweeter.
Silk Dome Tweeter can sound silk,but can roll of the high frequencies(called as warm sound).

Now there are some more facts we all would like to know from DIY experts.like-

1.How to combine the Driver?Selection?
This is very important as if we select the 2 way combo just by reading the specifications,final sound can be just Headache.There may not be a coordination between Bass & Treble sound.The drivers can behave like individual units.

2.How to select sensitivity of Drivers?
Now sensitivity of woofer can be different that the tweeter.eg-
Woofer can have sensitivity of 90db & tweeter can have 88db.So does that mean woofer can be dominant here?In opposite situation, will tweeter output more than woofer?

3.How to selecting Driver material?
This is also can be a must know point.If we select aluminum tweeter & woofer also made of light aluminum ,then will the final sound ear fatigue?
Is it wise to select silk dome tweeter with that to balance sound?
The same way a Kevlar woofer always sound good with aluminum tweeter?

4.Crossover?
How to select this?Is it the blind way to have separation point at overlapping frequencies of individual drivers?
Say woofer has the top frequency output of 3k & the tweeter starting point around 1k.So will it be 2k as straight option?

5.The perfect sound?
Finally is there any best combination of Drivers which can be paired with warm as well bright sounding stereo amp?(so called neutral sound).
I have found that polk RTi series is paired with Denon,Onkyo,Yamaha easily without missing details.

So experts,pls.do guide for building DIY speakers.Dont forget to mention the required budget too.

Thanks.

 

[anm]

I had exact same questions in my mind for a couple of days. A speaker design is eating my head for last few days.

 

[aashish351]

I too have gotten bitten by the DIY speaker bug... Tyring to find quality drivers (Peerless, Vifa, Fostex) availability in Delhi, with no luck so far...

 

[spirovious]

Thanks,
Peerless are easy to get Locally(India).Other can be Seas,Dayton.Designing & getting best out of the drivers is a skill.I know there are experts here & need to learn from them.I am looking to build 2 way Bookshelf speakers.some thing like-
http://www.parts-express.com/projectshowcase/indexn.cfm?project=karmaindignia

ZAPH AUDIO SR71 - YouTube

 

[Flash]

Guys I think we have to segregate the questions .

Because each answer is pretty vast with multiple view points.
We are basically talking about designing a complete loudspeaker from the ground up sans cabinet design

I started with first question and it ran into several paragraphs
I gave up half way through.

 

[pupupuchi28]

You can add another question...I might sound dumb.
- If we have a 4 ohms tweeter and 4 ohms woofer over a crossover, if the resultant impedance 8 ohms. or 8ohms tweeter and 8 ohms woofer over a crossover will give overall 8 ohms for the speaker.

This thread should be really helpful to me.

 

[Flash]

You can add another question...I might sound dumb.
- If we have a 4 ohms tweeter and 4 ohms woofer over a crossover, if the resultant impedance 8 ohms. or 8ohms tweeter and 8 ohms woofer over a crossover will give overall 8 ohms for the speaker.

This thread should be really helpful to me.

you can make a 4 ohm or 8 ohm or even 6 ohm Depends if it is connected in series or if you add a L pad.

Actually your impedance purely boils down to your crossover design

 

[doors666]

Why do you want to design your own speaker, specially when you dont have any knowledge on this, why cant you find a suitable design, by a reputable designer. It would probably take you a long time before you can probably design as well as a dennis murphy, danny ritchie, troels, krutke etc. You will probably be working real hard for about 2 years before you can turn out your alpha version and then probably realize it aint worth it and give up. You also need measurement equipment and that doesnt come cheap. Figure the cost of multiple sets of drivers over time, different cabinet, crossover components costs etc. And Next you will want a 3 way, and then will you also be designing your own amp? Why not just make a pass f5?

Sorry, dont want to sound discouraging, but thats the reality. designing a good speaker is not an easy task. Its a lot of art and science. There is a lot of time, effort and money involved. Though if you just want to slap something together and get some decent sound out of it, then it might not be that hard, but a really good speaker, now thats a different ball game all together.

My suggestion to you is to decide on what budget, sound etc you are looking for and identify the design you are looking for. Most of the designers are quite decent people and help people out with questions etc. Make a few speakers, and if not satisfied, then take a call if you wish to design your own.

If you still decide to go ahead with it, good luck, we all will provide what ever help we can

Hi friends,

I am very new to this section of forum.May there others too who may need to know the subject.I have been reading other sites & learnt that one should get correct driver combination to get good sound out.

Some of the facts that if someone need detailed sound(said to sound bright),he has to choose probably Aluminum Tweeter.
Silk Dome Tweeter can sound silk,but can roll of the high frequencies(called as warm sound).

True, but as usual there are exceptions, e.g. dayton rs28f is silk and rs28a is aluminium, they exhibit opposite behavior.

Now there are some more facts we all would like to know from DIY experts.like-

1.How to combine the Driver?Selection?
This is very important as if we select the 2 way combo just by reading the specifications,final sound can be just Headache.There may not be a coordination between Bass & Treble sound.The drivers can behave like individual units.

Not really, as long as a few things are taken care of, you are good. primarily there should be a good freq overlap between the two. impedance and sensitivity dont matter much. there might be a few more things though, not sure.
The coordination part is done by the crossover. distortion (both linear and non linear) causes headache. There is always a chance that even of everything is fine on paper, the combo just doesnt work together (read that as doesnt sound that great). there is no way to find out this until you try it out. Try to use the drivers that have already been used in a build by someone else with +ve results to avoid the possibility of this.

2.How to select sensitivity of Drivers?
Now sensitivity of woofer can be different that the tweeter.eg-
Woofer can have sensitivity of 90db & tweeter can have 88db.So does that mean woofer can be dominant here?In opposite situation, will tweeter output more than woofer?

You can always pad the tweeter. thats reducing the efficiency, by using the crossover. I have heard of people not doing this and still getting good results. Not sure what technique they use.

3.How to selecting Driver material?
This is also can be a must know point.If we select aluminum tweeter & woofer also made of light aluminum ,then will the final sound ear fatigue?
Is it wise to select silk dome tweeter with that to balance sound?
The same way a Kevlar woofer always sound good with aluminum tweeter?

The metal drivers are usually more resolving than their paper counterparts, but the paper ones have smoother sound. You dont need to worry about bright or warm etc as you are the one designing the xo, so you can tweak all that to suite your taste. This is the biggest advantage of designing your own speakers, you can tweak it to your heart's content, make it suit your room and all that.

A 0.75" tweeter will probably not go lower than 2.2khz, but a 1.25" might go down to 1.2khz.
A 4" woofer will cover say from 80z to 5khz, while a 8" will go from say 40hz to 1khz. extrapolate. there are always exceptions

4.Crossover?
How to select this?Is it the blind way to have separation point at overlapping frequencies of individual drivers?
Say woofer has the top frequency output of 3k & the tweeter starting point around 1k.So will it be 2k as straight option?

Nope, its not that straight forward. What I have seen is that usually people try to take the tweeter to as low as possible without creating other problems. I believe its because the woofer might start beaming at higher freq. Another reason for that is if your tweeter goes real low, say 1khz, then you can use a larger woofer, which will give you much better bass. If you crossover at 2khz, there is probably no 8" woofer that can go that high. A 5" driver will take you to about 4-5khz, but might not go below 80hz.

A tweeter that goes low will usually be larger as well as more expensive. Thats where waveguides come into picture, you can take a smaller and cheaper tweeter, add it to an appropriately designed wave guide and it will go much lower.

5.The perfect sound?
Finally is there any best combination of Drivers which can be paired with warm as well bright sounding stereo amp?(so called neutral sound).
I have found that polk RTi series is paired with Denon,Onkyo,Yamaha easily without missing details.

So experts,pls.do guide for building DIY speakers.Dont forget to mention the required budget too.

Thanks.

I think you are putting too much of importance to drivers, while the crossover is the most important part of the speakers.

There is no best combination, if it was there, everyone would have only that.

You need to decide the budget. The cabinet and the painting can be done by professionals for a small 2way for some 2-3k. Rest is drivers, crossovers, wires, binding posts etc.

 

[ukjeyaraj]

I fully agree with above post.

I am not an expert, but I can tell what I did.

1) Chose drivers with same impedance (all 8ohms).
2) Looked for specs that cover entire frequency range (i.e., together all 3 drivers should cover wide range).
3) Didn't bother much about cone material, as that alone does not make much difference in sound quality
4) Sensitivity, its difficult get matching drivers. Hence chose something very close and handled the difference in xover design.

Now coming to crossover, this is something, which should never be purchased off the shelf. Precisely because you will never get matching drivers that are made for one another. Crossover needs to be designed and built based on the strength and capability of each driver. Similarly box needs to be designed and built. Software used for designing crossover and box are xover pro and boxpro. Getting xover components in India is almost nightmare. Finishing of box is another topic to discuss.

However, I did DIY FS speakers starting exactly with the kind of questions OP has posted. But over the time learn, there is no straight answers for any of these questions and I enjoyed the complete journey of learning. Infact I am interested to do a 2-way bookshelf now.

Experts can still help with some thumb rules to be followed, atleast to the extent of choosing drivers.

 

[navin advani]

Some of the facts that if someone need detailed sound(said to sound bright),he has to choose probably Aluminum Tweeter.
Silk Dome Tweeter can sound silk,but can roll of the high frequencies(called as warm sound). Now there are some more facts we all would like to know from DIY experts.like-

1.How to combine the Driver?Selection?
2.How to select sensitivity of Drivers?
3.How to selecting Driver material?
4.Crossover?
5.The perfect sound?

First there are soft dome tweeters that have been more lispy and forward than metal dome tweeters. There is no rule that dictates metal dome tweeters will sound more forward. The SS 9800 is one example of a metal dome that is very good. SS new Be dome ($500 each) Illuminator is another.

Driver selection is part art and part science. A paper cone woofer can sound good with a metal dome tweeter and vice versa and there are many examples from Troels, Tony Gee, Zaph, Jim Salk, Rick Craig, Dennis Murphy, Paul Kittinger, etc.. of speakers that combine drivers of different materials.

Usually the woofer needs to be 3-4 db more senstive than the tweeter to compensate for baffle step. The tweeter is uaually padded down to match the woofer.

Choosing Crossover parts is part common sense part expereince.

I made this post not long ago on another forum.
"Many years ago (early 90s) I was visiting a rather well known speaker designer. In his lab I saw a rather simple 6" 2 way speaker half finished. I was surprised that there was a electrolytic cap in the tweeter circuit so obviously I asked. He said the cap's sonics were part of the design and when he removed the electrotytic and replaced it with a "esoteric" cap of the same value the speaker did loose it's "danceability". After that experience I dont question methods of people who know far more than I do. There is a method in their madness. In the end it is the music that matters. "

Lastly. Perfect sound is subjective. We all have our opinions.

 

[spirovious]

Why do you want to design your own speaker, specially when you dont have any knowledge on this, why cant you find a suitable design, by a reputable designer.

Well,I have no intention to design myself,but surely with the help of good designer.
But what do you think,should I simply go to him,tell my requirement & just get my product which he thinks & makes?
When we buy a product,say HDTV,we do our homework(atleast I do),know the technical specifications,features & then take Demo.
If I go without basic knowledge,then there can be a chance that I may not like the sound of speaker make.I may not even get a prior demo of one I am asking him to make.

So thats my views.

 

[GeorgeO]

T Antony is doing a build, why not check the thread out?He is using Peerless locally available drivers. If you start getting into nitty gritty without reading up, it may not be as useful as doing a build AND reading up. As Vikas said-first define your budget.

 

[anilva]

There are so many posts in this forum on speaker building including on basic principles like the one you are alluding to. The answer to the questions you have posted is going to be like a treatise. No point in writing them all over again, when there is excellent info available on this forum as well on the net. Please take time and read up. Once you have a good basic understanding, it makes sense to have a specific discussion not a generic discussion.

Cheers.

 

[spirovious]

As Vikas said-first define your budget.

I read that basic BS speakers can be built for Rs.10000 around.I will look for a solution in the price range around Rs.15-18K.

 

[spirovious]

No point in writing them all over again, when there is excellent info available on this forum as well on the net.
Cheers.

True,but this thread can be a basic guideline for the new DIY members & not as individual projects(not only mine).It can be made Sticky later if found helpful.

 

[doors666]

I read that basic BS speakers can be built for Rs.10000 around.I will look for a solution in the price range around Rs.15-18K.

You can definitely get a good speaker for that price. You can import some kit also. how about the group buy going on. the shipping etc wont be too much if its using a 4-6" drivers. also check the full range options. check the kits thread in diy

 

[avidyarthy]

ehehehe .... doors ... that what I PMed him just now, before you chipped in.
Fostex driver based speakers takes the cake in DIY!

 

[Sumanta]

I think Open Baffle speakers are the best value for money option. You have to read, understand, visualize and then make it. Making it is the easiest part..and you do not have to search the best speaker maker. Any carpenter can make one or two holes in a plate of MDF or plywood. Attach one or two hinges depending on your driver selection, room, your preferences.
My personal experience with Indian make Ahuja PA loudspeakers is quite good and excellent value for money.
Two things are for sure to happen...
You will not stop in making just one pair of speakers
You will learn and enjoy the whole process more than enjoying the music that you have enjoyed so far.

Open baffle design concept will open the basics to you with less complications yet it usually ends in a good result. Open, clear sound of any driver will surprise you a lot.

And yes, you can have a budget of just 5K too, yet get a speaker of high efficiency.

Understand what driver chracteristics like Thiele / Small parameters means and how they affect permance of a driver under certain circumstances, understand how a driver works {at least a wide bander (a.k.a Full ranger)}, compare Indian drivers with foreign ones, decide the compromises you can make. Then make the speaker one day.

 

[Sumanta]

One more thing to remember if you do Open baffle, that the speakers should be kept at least 3 feet away from the back wall of the speakers. That is a lot of space.
I place those speakers 3 feet away only when I listen to music. Otherwise they stand thouching their back with the wall, and being less deep than any usual floor standing tower speaker, they most of the time take less space in a room. They are lighter than usual tower speakers, so it is easy to move them. My one speaker with a 15 inch woofer and a 12 inch full ranger is lighter than my Cabasse tower speaker which has only two 6 inch woofer and one 1 inch tweeter.
Open baffle speaker with hinged side wings are better for small listening rooms.

 

[Sumanta]

One very important thing to decide is whether to go for passive cross over road or Active cross over road.
I think this decision alone makes a lot of change in your budget and the way you can control your music system's sound as a whole.
I prefer active cross over as it is having better value for money and also this is a fact that I do not want to delve into electronics. Active cross over path can be followed with minimum investment and can then be indulged in for more (if required). Having an amplifier which can do bi amping (like many today's Audio video receivers) is a good start.
A stereo amplifier for mid and high and another one dedicated for woofer will not cost you much compare to the output quality (and control) that you will get. Amplifier for woofer generally have in built cross over which works to some extent.
But in this way you have to be dependent on a laptop or an active cross over at some point of time. Or else, you need to get a mini DSP.

Passive cross over (good one) cost a lot and if designed to a specific driver combination can be then considered as an Indian marriage.
Bottom line - DIY is not a smooth road but an enjoyable adventure. And the only road for a poor man who wants a Jamo R909 in his home.
I personally do not have any other option but to do DIY now. I am addicted to it.