Full range speaker thread.. dedicated post on frequency response and imaging of full range speakers

[Subcenter2009]

Dear friends,
Full range speakers are those whose cabinets do not have tweeters or woofers.
They may have 1 or more full range drivers or dual cone speakers.
They usually lack low end Bass extension but are usually excellent performers when mated with a suitable subwoofer or two...
Sibilance is usually minimal in these speakers.
Since there is no overlapping of frequencies as normally seen between Tweeter/midrange/woofer in cheaper 2/3 way speaker towers, sound seems more consistent and the presence is more realistic.
I will start this thread talking about the Bose 161, a true full ranger with fantastic 3 dimensional imaging. But as expected, they lack bass and require a dedicated sub with which, they are truly world class.
And, if you are going to use a subwoofer, they will not burn a hole in your wallet.
They have 2 large excursion 4" drivers in each cabinet.
But they, when installed decently, have a rare quality of beautiful 3D imaging which crossed over 2/3 way speakers really lack.
Frankly, They are among the best i have ever heard.
Now I have made a beginning.. now I welcome fellow members to post your love/hate relationships with true full rangers.
I have also heard some awesomely decent sounding dual cone driver speakers. I am including dual cone speakers in this genre.
So friends, please post your love hate relationships with fullrangers.

The Bose 201/ 301 etc are not true full rangers as they feature a tweeter. But 901 may fall into the fullranger category.

Most commonly found home theater satellites may either be full rangers or 2 way. But world beating full range speaker units are a class by themselves.
You must hear them to understand what i am raving about.

The Bose 161s are also excellent surround speakers for a home theater and are rated at 10-100 watts RMS.

.

No. I don't work for that company.. but am just an admirer of true full range speakers.

 

[tuff]

I am sure few DIY forum members would be interested to opine. I myself am a planar guy so not much use over here. Nor have I heard many full range speakers to give any opinion. But would be interested to see what others have to say.

 

[Subcenter2009]

You can also have speaker towers with any number of full rangers.
The advantage is: all the drivers are always in perfect phase with each other.
Subcenter2009

 

[Ravindra Desai]

Hello Subcenter2009,

Thank you for starting this thread!
I am a die hard full-range person.

Here is the plan for the most amazing full-range speaker that you can diy:

Driver: Ahuja SK-12FRX
Enclosure: 18mm MDF
Dimensions: W x H x D: 56cms x 144cms x 91cms
Ports: 3nos, square
Port size: 10.2cms x 10.2cms x 10.2cms

The enclosure is braced inside at 1/3 and 2/3 height.

I know the enclosure is huge. But hey, if you want the quality of Tannoy Prestige Gold (or may be even better), then you got to make a sacrifice somewhere.

I have made 6-8 pairs of these, and sold all of them. Sorry, I don't have pictures.
I will soon be making another pair since there is a growing interest for stereo, in Kolhapur!!

Ahuja SK-12FRX with its company recommended enclorure sounds like crap. However, try simulating it in WinISD to understant its value. Its GOLD!

With the stated enclosure, the bass is tight, full that you can hear and feel. The mid-range will wow you. The treble is detailed and smooth.

Caution: If you listen to the above recommended speaker in the recommended enclosure, everything else will seem dull.

Regards,

Ravindra.

 

[Hari Iyer]

I recently built a OB module using Russian Vintage drivers and since then enjoying musical nirvana.

 

[Hari Iyer]

However, try simulating it in WinISD to understant its value. Its GOLD!
.

WinISD is a box simulator and does not show response above 1000Hz. Also it does not input the FRD & ZMA values. You need to enter the measured TS parameters for this.

I will recommend other simulation software like Basta, Leonard Audio (LA) for simulation with measured parameters.

My 2 paise.

 

[Ravindra Desai]

Hello Hari, Yogibear,

Thanks for your concerns about using simulators.

For my work, both, in electronics design and loudspeaker design, I use MS Excel. I do not 'depend' on PSpice or WinISD. Excel, is perhaps the best thing that MS has done for mankind!
My reference to WinISD was for all to get an idea of this build's capability at low end and why such large enclosure volume is required.

Long story short: I know what I am talking about when I posted this plan.

The Long story: Before posting an enclosure plan in public, I have ensured that I have built it my-self (not 1 but 8 pairs that I remember), tested it and found it able enough to share it with you all.
This plan is the best contribution I can make to this forum. I have not heard better Bass than from this build! Period!! Titanic- Track-1 will make your hair rise and you will have lumps in your stomach. Its not just about what you hear, but also about what you feel. How many sub-woofers, costing < Rs. 20,000/- can do that at <5W?

So go ahead and build it with confidence.

Following are some details about using a this full range build for audiophile listening:

1. The Ahuja SK-12FRX has a sensitivity of 97db!! So for home listening, the recommended amplifier is 5-20Wrms. That is all.
2. The speaker has a cloth surround. It will need a break-in period to perform to its full potential.
3. This build is NOT recommended for Rock and Heavy Metal type of listening.

Have fun!

Ravindra.

 

[VSTEREO]

I have recently got into Full Range. Currently using Dayton Reference RS-100 4ohm. Its a small 4" speaker but sounds BIG and very versatile. Midrange is treat to listen.

 

[Hari Iyer]

@ Ravindra,
Large / Huge speakers are a big no for Mumbai type homes due to poor WAF. Else would have thought of the Woden Victor for the Fostex. Even my current OB speakers obstruct some space in my living room and others in home have to live with it.

I am not sure about this particular Ahuja driver, but the box volume required depends upon the driver stiffness and compliance. If the driver is low stiffness (means it has high compliance) then the box compliance should be small (ie. box should be high stiffness). For a high stiffness driver you will require a high compliance box theoretically.

The driver compliance and the box compliance add up like capacitors in series and the net compliance will be low. The compliance usually is adjusted to keep the Qtc of the speaker system roughly around 0.71 for maximum bandwidth and critical damping.

 

[Ravindra Desai]

Well, the response is picking up so let us get to the devil by looking into the details:

1. With a multi-way speaker, the amplifier is looking at the crossover network. A good, correctly designed crossover network always offers constant impedance load to the amplifier while dividing the frequencies. So 90+% of the amplifiers found in the market today work well with multi-way speaker because the amplifier is delivering power into a constant impedance load.

2. With fullrange speaker, there is no crossover network. So the amplifier now looks directly at the speaker impedance as load. The speaker impedance of a 4ohm speaker varies anywhere from 3ohms to 20ohms. The speaker impedance of a 8ohm speaker varies anywhere from 6ohms to 40ohms.
This results in drop in output power below say 200Hz and above say 4KHz due to rise in speaker impedance.

So you will find that 90+% of the times, fullrange will NOT satisfy the customer.

The remaining 10% of the time, you are either dealing with 'special' semiconductor amplifier designs (like mine, detailed here) and valve amplifiers.

So what is different with these amplifiers?
Valve amplifiers have large output impedance which results in a very low damping factor. Typically around 10. This makes the amplifier to deliver constant current even if the load impedance varies.
With my amplifier too, I have tweaked the feedback loop so that power increases with increase in load impedance and decreases with decrease in load impedance (thus supporting short circuit load, where it does not have to deliver any power!)
So with these 10% of the amplifiers, power delivered into the speaker actually increases below say 200Hz and above say 4KHz as the speaker impedance rises. Thus making them silkier at the high end and responsive deeper into the low end.

Now the hell is going to break loose because the gurus, or rather, the gooroos all over the world have said higher the damping factor, better is the amplifier. Well, they certainly are gooroos, but in the sales department as it allows them to rightfully sell expensive, multi-way speakers. People don't feel fooled as the agree to paying more for better sounding speakers.

So now let us try to apply this to the reactions I got above:

I have recently got into Full Range. Currently using Dayton Reference RS-100 4ohm. Its a small 4" speaker but sounds BIG and very versatile. Midrange is treat to listen.

Try connecting these to a valve amplifier (or my amplifier) and see how the lows and also the highs bloom!

.....and when you get to drive them with tube, it’s quite some nirvana.

I believe you! Nirvana indeed!!


Subcenter2009: Where are you? You started this. Now you cannot hide.

Regards,

Ravindra.

 

[Hari Iyer]

So you will find that 90+% of the times, fullrange will NOT satisfy the customer.

I have come across some FR speakers which usually are not FR speakers in the true sense. Consider the Fostex FE166en - they require serious support at the bottom and the top end due to their roll-off at 100Hz and 10KHz. I have seen the Lowther DX-4 too requiring support at the bottom end (e.g. Rethem speakers). So is the case with Dayton Audio and other FR speakers that i have seen. The Ahuja 12" driver too could suffer from these issues (but i have not heard them). Only measurements can confirm actual roll-off of these drivers.

My recently build OB speakers with vintage FR drivers is a class apart which has good flat response from 40Hz to 20KHz, which i have not seen even in an super expensive Voxativ driver. Now critics will start arguing that freq response is not the only thing to consider in a speaker & many other things ........................... without telling what else to consider other than subjective listening.

 

[Hiten]

vintage FR drivers is a class apart which has good flat response from 40Hz to 20KHz,

40hz to 20khz will be the most extreme wideband. Which speakers are these ?
Regards.

 

[drgb]

@ravindra sir: sir please can you share some more details (drawings, etc) about the enclosure you are talking about. I am just about to buy the ahuja 12 inch full ranger; i will definitely use your plan for the driver and update here.

 

[shafic]

So what is different with these amplifiers?
Valve amplifiers have large output impedance which results in a very low damping factor. Typically around 10. This makes the amplifier to deliver constant current even if the load impedance varies.
With my amplifier too, I have tweaked the feedback loop so that power increases with increase in load impedance and decreases with decrease in load impedance (thus supporting short circuit load, where it does not have to deliver any power!)
So with these 10% of the amplifiers, power delivered into the speaker actually increases below say 200Hz and above say 4KHz as the speaker impedance rises. Thus making them silkier at the high end and responsive deeper into the low end.

Nicely explained!!
Regards.

 

[Hari Iyer]

40hz to 20khz will be the most extreme wideband. Which speakers are these ?
Regards.

These are the Soviet era vintage drivers 10GDSH-1-4 originally made in 1955. From 1980s onward the paper cone for this driver was supplied from Japan to make it more softer & lighter. This driver was under production in Siberia till Y2K and has become vintage after that.

Attaching my measured FR response.

 

[sunder]

With fullrange speaker, there is no crossover network. So the amplifier now looks directly at the speaker impedance as load. The speaker impedance of a 4ohm speaker varies anywhere from 3ohms to 20ohms. The speaker impedance of a 8ohm speaker varies anywhere from 6ohms to 40ohms.
This results in drop in output power below say 200Hz and above say 4KHz due to rise in speaker impedance.

Dear Ravindra, can we use a vintage tweeter of 11 ohms connected in series with First Order cross over (4 uF - 100v) to a vintage full range speaker of 4 ohms? or the impedance of both FR & Tweeter should be same? Thanks.

 

[Hiten]

Thanks Hari.
Regards.

 

[Ravindra Desai]

Dear Ravindra, can we use a vintage tweeter of 11 ohms connected in series with First Order cross over (4 uF - 100v) to a vintage full range speaker of 4 ohms? or the impedance of both FR & Tweeter should be same? Thanks.

It will be a hit or miss type of an exercise and I don't recommend doing it.

Multi-way (2/3/4) speakers is not a good idea for DIY.
There are just too many parameters that need to be considered that just goes beyond the scope of a discussion in a forum post. Sorry.

The best I can suggest, if you have to DIY is look for a kit from a branded company that gives you both Woofer, tweeter and the crossover along with the enclosure plan. I know, then you are just left with assembling it. Philips use to do that back when I was in college. But now they are no more in the market.

@ravindra sir: sir please can you share some more details (drawings, etc) about the enclosure you are talking about. I am just about to buy the ahuja 12 inch full ranger; i will definitely use your plan for the driver and update here.

Attached is the plan for your ready reference. I hope that you have reat post # 16 in this thread and understand it fully.
This plan is going to occupy huge space. I recommend you build a thread model to understand it. Double bracing as shown is a must!
This is also going to be super heavy and will need 2-3 people to carry each speaker.
If this is your first build, I recommend you don't attempt it unless you have some experienced person accompanying you all the time.
Good luck!

Regards,

Ravindra.

 

[drgb]

Thanks a lot for sharing the design sir!

Just a couple of quick questions:

1. The given depth is too deep for my purpose. What if i mount the speaker on the side that is 91cm keeping the rest same? Would it destroy the plan or would have no effect?

2. You have made the ports in the middle third of the speaker; can these be made in the lower third (nearer to the ground that is)?

3. What sort of stuffing/lining material you suggest? (Or none)?

Thanks again for sparing your time!

 

[Ravindra Desai]

Thanks a lot for sharing the design sir!

Just a couple of quick questions:

1. The given depth is too deep for my purpose. What if i mount the speaker on the side that is 91cm keeping the rest same? Would it destroy the plan or would have no effect?

2. You have made the ports in the middle third of the speaker; can these be made in the lower third (nearer to the ground that is)?

3. What sort of stuffing/lining material you suggest? (Or none)?

Thanks again for sparing your time!

1. W, D, H are interchangeable.
2. Put them preferable where they will not be easily obstructed.
3. For ported enclosures, I do not have any theory to support stuffing. So none.

I hope that this helps.

Regards,

Ravindra.