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My First DIY Project...Full Range...And LOTS of questions !
My First DIY Project...Full Range...And LOTS of questions !
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Old 23rd November 2020, 02:20 PM   #1
aum235 is offline aum235
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Default My First DIY Project...Full Range...And LOTS of questions !

Hi Folks,

First let me start by saying that, in my humble little part, I am very happy to be part of this community !
Although I have subscribed to the channel already quite some time ago, this is my very first post, so first a short presentation is the least one should expect :

My name's William, I'm a 50 years old French/US citizen, have been living in China for over 6 years now (Beijing). I'm an interior designer.
I love audio and music of course, music is an important component in my life and well being. I listen to all sorts of music really, but probably 50% +/- goes into house and techno, as I used to DJ before (in the 90's, also in China, after which I went back to France for 14 years).
But Rachmaninov, Tchaikovsky, Queen, Supertramp, Bowie, Bauhaus, Ella and Louis, Dead Can Dance, Muse, and so many so many more...they all sound great to me, so I am quite eclectic.
I don't spend hours in audio stores or what, but back some 18 years or so ago, at my best friend's place in Paris in listened to some music (it was hardcore techno !) coming out of some old speakers wired to an old tube amp he had found at the flea market back then.
And let me tell you, that sound ! My first time listening to a tube amp...I was convinced !

A few years later I got my first little tube amp (a hybrid actually) that eventually, after some run-in hours, finally kicked-in one day, when listening to Adele at the Royal Albert (could find worse choice for a kick-in, right ? ) while having lunch (The sudden difference in sound almost made me drop my fork).

Anyway, since then, I always wanted to go "Rogue" aka DIY because...well just because !
But never had the time before now.
But now, finally, HERE I AM !!!

So, now, for the project :
1 - My Goal : is to build a pair of speakers that are fairly to very efficient, each with a single full range driver, that can deliver a rather clean crisp sound and rather fairly flat all across the spectrum, right out of the speaker without any electronic assistance.
Bass has to be full and rich all the way down to the low 40s (even lower would be better uh !).
The cabinet doesn't need to be a tiny small one, as I am not looking to do a bookshelf speaker but rather more something that looks like a statement in the room.

2 - Components :
The Driver :
6 months ago I bought a pair of 6.5" full range drivers - aluminum cone - these are from a Chinese brand that some of you may know called Lii Audio.
I'm not gonna bring up all the TS for now, but for a rough idea :
SD = 132cm2 / Qts = 0.617 / Vas = 29L / BL = 6.349 / Fs = 42.853 Hz / Spl = 91.8 db

The cabinets :
Using Hornresp, I designed and then built a pair of MLTLs for my drivers. In the end they look a bit like some MarkAudio pensil series.
I used no BSC, because I don't want to loose on efficiency (more on this later) however I did try and minimise baffle diffraction (at least for mids and Highs):
The Baffle part where the driver is placed is on a recessed panel of 20*20cm, and which I then covered with a 9mm thick sound absorbant material (looks a bit like some kind of very stiff felt) that I use for covering walls in home theater rooms when I design homes.
Of course I cut a whole of the size of the driver cone in this material before putting it in place.
When playing music, the difference in the sound is very noticeable whether putting on this part or not, so clearly it is having an effect at canceling or reducing some of the baffle diffraction.
These speakers are (internal dimensions) : H95cm * W20cm * D33cm.
Fb is tuned at 35Hz or 40Hz that just depends if i add or substract an additional layer of plywood (18mm thick) in the horizontal vent located at the bottom of the front baffle. However placing this additional piece or not doesn't to make much of a difference in the end when listening.

The Amp :
A chinese tube Amp that's got a lot of good reviews from everywhere (the audiophiliac among all but not only).
It's the Reisong A10, Ultralinear, with El34B tubes, 6W per chanel.

3 - My impressions up to now :
For a first try, I would say not too dispointed, but can't either say completely satisfied !!!
First I placed the speakers about two meters appart, in a room that is about 5-6 meters wide.
The sound coming out was ok but...the bass seamed a little slimish if I placed myself in an about equidistant triangle from both speakers (a more or less normal listening position)
But then if I placed myself almost in line between the two speakers then the bass comes out. So there is Bass.
So then I tried placing the speakers close to the corners of the room (about 80cm inward from each corner) and tilting the front baffles toward the center of the room aka the listenning position and then...Tadah the bass wasn't so slim anymore.
So yes there is thumping bass coming out of these but depends on the position, cause it seems like a lot of it is leaking on the sides.
Then, as there is no BSC applied, I'd say the mids are a slightly too present sometimes, but IMHO it's in an acceptable limit still. As for the highs they feel fine to me.

4 - But then I do have a bunch of problems/questions :

What would you suggest for that bass "leaking" on the sides problem ? BSC ? Change cabinet - side vs front&back - proportions ? You see, MA's pensils designs specify that these cabinet designs don't realy require BSC, so I figured that My design, very similar to a pensil, could also get away without it.
External dimensions are 23.6cm wide (front baffle) x 40cm long (sides). What if I inverted these proportions ? What's your experience with this ?
Could it be some kind of bass cancelation in relation to phase or something else ?
Or could it be that my alignment isn't that good ? How should I calculate this then ?

This brings me to another important question : how far can I trust Hornresp in the design of my MLTL ?
Any other serious software options for MLTL ? (besides MJK's mathcad work sheets).

Then, something else that is bothering me is the power :
Granted, it's only a 6W per channel, but if I want to feel a bit of power in the music, I really have to turn the knob all the way up ! the room is basically a 6x6 or 6x7 meters wide.
is that too much for my combination ?
To be honest I am more suspecting the driver or the amp to be wrong somewhere :
a) When running the specs of the driver in WinISD, it tell me that driver's spl is in fact 87db ! If it where you, would you believe more the written specs or what WinISD calculates ?
b) As I mentionned before, my tube amp is an ultralinear one, but nowhere can i find the amp resistance output. What I am saying is I don't know if this is actually a high Z amp or not. It is An SET though, as far as I know. So should I consider it a high Z amp ?
And if yes, am I then right to assume that it is because it is a high Z amp that it's not putting out as much power as I would hope...especially if the drivers are in fact 87db one ?

Should I just change drivers ??
If Yes, for what I want, which one of MA would you recommend ? I am considering CHN110 or CHR120. What do you think ?

OK, I am sorry if some of you think this post is just too overwhelming, but I have great respect for many of the people in this forum, you guys know so much, so I sincerely hope you can provide me with hints or answers.

Those of you who will have read it all, thank you for your patience and understanding !

In these very difficult times I truly wish you all the best.
Stay safe, stay very safe ! Don't do anything stupid.

My Best regards to all.
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Old 23rd November 2020, 02:35 PM   #2
picowallspeaker is offline picowallspeaker  Italy
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Quote:
Then, something else that is bothering me is the power :
Granted, it's only a 6W per channel, but if I want to feel a bit of power in the music, I really have to turn the knob all the way up ! the room is basically a 6x6 or 6x7 meters wide
why don't you change amplifier, say a push-pull type? I mean....
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Old 23rd November 2020, 02:56 PM   #3
waxx is offline waxx  Belgium
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The amp is to weak for the driver, or the driver to inefficient for the amp. 87db drivers need a 32W amp to get to the industry standard max volume of 102dB. And the xmax of this type of drivers is in general low, wich i think is the major issue. But without specs i can't tell. I don't find a driver that looks like that on their site.

The MA drivers are all 85 to 89dB effcient, so also need a little bit more watt than that 6w you have if you want volume and bass out of them. But they mostly have a better xmax. My favoriete is still the Alpair 10.3M. But the two you mention are also great.

But if you want to keep using that amp, you need drivers that go above 95dB efficiency i think, and have a decent xmax. Not many do that. Lii has their Christal6 that should do that on dB but no xmax is mentioned (so I suspect it's low). Some Fostex drivers can do that also, but most high efficent drivers are big, bigger than that will fit your speaker cabinet.

What i would do, is make a sub to complement this setup, so you can use all the 6w for the higher up frequencies and use a different amp for the sub (Push Pull tube or solid state). For crossover, you can use passive or dsp at around 100Hz. I would tend to use passive but many will disagree as passive is harder to do it right... For sub drivers, look at SB acoustics (made in Indonesia i thought). They have many great subwoofers and they are not that expensive for the quality they deliver.
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Old 24th November 2020, 04:42 PM   #4
aum235 is offline aum235
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Thanks for you replies guys,

Actually, what comes out from both of you mainly is "change the amp"

Indeed that could be an option.

But before considering that option, I wanna be sure that I have, for my current driver, and with my current amp, the best cabinet design to draw out the best spl and the most bass out of this cabinet (with a response as flat as possible of course).

Also, considering an additional sub on the side is not really the route I intend to follow, at least not for now.

Also, Waxx, you mentioned once or twice the Xmax in relation to the bass...well, not sure I agree with you there, see.
First, indeed I myself don't know the xmax of my driver, but it's got a nice round rubber all around, and when pressing on the cone downwards, i'd say it has an excursion of at least 5mm one way.
And then, again in hornresp, with that specific design, cone excursion above Fb is less than 3.5mm at most at maximum amp power.
And last, some guys are able to have a fostex fe103en sing down in the 30's in a proper (and not so big) TL, and let me tell you that driver only has like a weee little bit of excursion...

So you may be right, maybe, but I do think there is maybe some tweaking to first consider doing on the cabinets rather than right away thinking to change drivers or amp.

Also, about MA, you perhaps noticed on their site that in all the speaker cabinets they design, some are specifically taylored for SETs / high Z amps, which should mean - in my modest opinion - that with a correct cabinet design, you should be able to put out some substantial sound even with just a few watts (okay, but of course certainly less than with 95db speakers, granted !).
If someone's got that kind of configuration at home, could be interesting to get his/her opinion.

So yeah, I still wondering if there's anything more I could do to improve my cabinets, especially to try and get that bass sound less leaking on the sides.

Additionally hereby is a snapshot of all the TS params that I got when I bought these.
If someone here is courageous enough to calculate an estimated spl according to these TS, I'd be curious to see what you get.
Calculating in WinISD and somewhere else on the internet, I get around 87db, which is quite far from the almost 92 announced in the specs.

Everyone, take care !
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Old 24th November 2020, 07:02 PM   #5
SinGun is offline SinGun  Russian Federation
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Quote:
Originally Posted by aum235 View Post
But Rachmaninov, Tchaikovsky, Queen, Supertramp, Bowie, Bauhaus, Ella and Louis, Dead Can Dance, Muse, and so many so many more...they all sound great to me, so I am quite eclectic.
Rachmaninov, Tchaikovsky, Queen, Supertramp & Bowie dont go so good with FR. 70's rock & classic sounds IMO poor with the most FR. Philips AD-9710 is quiet OK with 70's rock & classic. But multi way (best 3-way) is far better regarding this kind of music.

The Tang Band W4-1337 Titanium cones (I have them in hybrid BR/horn enclosure) are probably the most linear FR on this planet but with 70's Genesis albums they sound like over the telephone! If you want audiophile grade symphonic orchestra sound there is no way with FR. For obvious reasons.
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Old 24th November 2020, 07:17 PM   #6
waxx is offline waxx  Belgium
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Sorry, i do listen to orchestral classical music with fullrange driver, the Mark Audio Alpair 10.3M in waw (woofer assisted wideband) config (so with a 10" scanspeak woofer) and it does it better than many multiway speakers i've heared. Small fullrange drivers (like that W4) won't do it, and many big also not, but some do, certainly in a waw config with some correction networks. And I'm not the only one who does that. But too many build wrong boxes for the wrong drivers and then say they don't work...

If you want high volume and a decent bass and dense music, a Waw is the way to go, if low volume or less dense music is your thing, then a good fullrange on it's own can do it also. And fullrange drivers often need a taming of the high, with a correction network or otherwise.
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Old 24th November 2020, 07:38 PM   #7
revisorn is offline revisorn  Sweden
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Hi Aum

Im not shure what you want to improve but I assume it is the bass. The easiest way is to move the cabinets closer to the back wall for improved boundary support.

The best way however would also be to include a baffle-step filter in series with the drivers. An inductor 1mH and a resistor 4 ohm in parallell with each other in series with the driver should work fine.

http://diyaudioprojects.com/Speakers...on-Circuit.png

If you lack treble you could also include a capacitor in parallell with the inductor and resisitor.

But as you know a compensation filter as above means lowering the mid and high frequency register. So you might need more power than a six watts amplifier to make it work.

If you want to increase the efficiancy of the drivers you need to employ some sort of horns. They are usually calculated for a specific driver and can be more complex to build.

Fostex BK-12m Folded Horn Kit - Pair

Last edited by revisorn; 24th November 2020 at 07:43 PM.
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Old 24th November 2020, 07:55 PM   #8
SinGun is offline SinGun  Russian Federation
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Quote:
Originally Posted by waxx View Post
Sorry, i do listen to orchestral classical music with fullrange driver, the Mark Audio Alpair 10.3M in waw (woofer assisted wideband) config (so with a 10" scanspeak woofer) and it does it better than many multiway speakers i've heared.
I just changed from Alpair 10.3 in BR to Philips AD-9710 in BR. Female voices on Alpair plain bad cos metallic. Philips better compatible with different music and much much more fun. Sorry but after 600h break in with the 10.3 my verdict on the 10.3 is: Yucky . Larger metal cones just dont work for me. With symphonic music the 10.3 cant even beat an old BBC 3/5. Even small 2-way speakers from Monitor-Audio, KEF, Tannoy, Wharfadale are all better with symphonics.

BTW, I stay far far away from Scanspeak cos all LS with Scans I've heard were sounding totally unrhythmic and unmusical. You can buy better woofers for less money like Seas for instance with even better quality control and better (tighter) tolerances.

Last edited by SinGun; 24th November 2020 at 08:00 PM.
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Old 24th November 2020, 11:05 PM   #9
Soundhappy is offline Soundhappy  France
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Large 12" or 15" drivers are the key to Audio Nirvana High Efficiency Full Range Loudspeakers
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