Diy Monitors - to build or not to build

[Kev]

[quote author="mhelin"]What's so attractive in D'Appolito configuration? It's okey technically (you will get louder speakers) but .... [/quote]

yep
more volume

it does work fine in a longer throw or PA situation but I do agree that it is not without issues

if only we could still get more efficient quality speakers
:roll:

 

[barefoot]

I suggest something like this: http://www.madisound.com/bigavkit.html

It uses mid priced Vifa drivers, so it's affordable. Cabinets are available for purchase for those who don?t have the facilities to build their own (I think very similar cabinets are sold through Speaker City and some European dealers as well).

The tweeter cutout will accommodate a variety of Vifa and Seas drivers. We could do variations on passive and active systems.

If you want something higher end, then I suggest something like this: http://www.madisound.com/solist.html

Again, the cabinets are available from a few sources. Plus there are several choices of Scan Speak or Usher drivers.

Thomas

 

[SonsOfThunder]

[quote author="mhelin"]What's so attractive in D'Appolito configuration? It's okey technically (you will get louder speakers) but .... [/quote]
I'm surre there is a better explanation han the following but I'll offer my understanding of a few reasons for Mr. D'Appolito's config.

1) Tweets are almost always more efficient than the mid-woofs. So this helps to balance the freq response out without throwing tweeter eff away.

2) There is a lobing effect that occurs in the vertical plane around the crossover point on any 2-way. This depends on several things, but the problem is that the lobe generally is aimed downward (or upward if the tweet is on the bottom). Some designs compensate for this by using a tilted baffle. But the D'App makes the lobe come out perpendicular to the baffle every time. The drawback is that there is sometimes a narrow "sweet spot" in the vertical plane.

Do a search or read the Loudspeaker Design Cookbook by Vance Dickason.

HTH!!

 

[mhelin]

[quote author="SonsOfThunder"]
1) Tweets are almost always more efficient than the mid-woofs. So this helps to balance the freq response out without throwing tweeter eff away.
[/quote]
Yes but you could use TMM as well to get the same efficiency.

2) There is a lobing effect that occurs in the vertical plane around the crossover point on any 2-way.

That can be solved by time-alignment in box like in B&W Nautilus:

or in crossover. Latter requires practically active crossover (it's possible to do in passive also). Also in passive speakers different types of crossovers have different lobing effect. Generally the LR type crossover arrangement (two Butterworths in series) gives best lobing effect.

But there must be something else. Tony Gee's Proteus for an example (likn above). He tried both 2 1/2 way and D'Appolito configurations, and what was interesting was that in the waterfall graph the bass can be seen to have less stored energy in D'Appolotio than in 2 1/2 way solution which otherwise sounded more open and wider. The reason in this case must be in crossover, as the 2 1/2-ways crossover with the large 3.9 mH inductor for sure stores more energy that the first one for the D'Appolito configuration. Studio monitors on the other hand usually use active crossovers and filters, though these are not free of the same sympthons either. DSP crossover with convolution (FIR) would be almost ideal - too bad this have the latency of half of the IR length used in convolution (in case of phase linear filters). The need for baffle step compensation really is one thing that makes the speaker design difficult, soffit (flush) mounting of speaker solves this but you can't always do that. Another solution could be using extra woofer to add energy below baffle step frequency, but the woofer should be selected so that the roll-off is natural for the element and no extra inductors are needed.

 

[PatinaCreme]

I have a question. So, with these kits you just stuff it and maybe some screws and you are done?





clueless
Patina

 

[pucho812]

pretty much like that maybe some minor solder required.

 

[barefoot]

[quote author="PatinaCreme"]I have a question. So, with these kits you just stuff it and maybe some screws and you are done? [/quote]

Yes, if you want it to be that simple. But there is lots of room for modifications to the drivers, crossovers and cabinets.

 

[Eric Best]

If you are into woodwork you build the cabinets. You can also order the cabinets and just stuff and solder.

 

[mhelin]

[quote author="kubi"]Sorry for hijacking this thread, but did anybody try to build an active freq. x-over before the amplifier and use then one amplifier for each driver? I'm interested if the difference (improvement) in sound is big or just hardly noticeable.[/quote]

I've tried my DIY speakers with passive and active x-overs. Tweaking passive is difficult but with active one it's easy to try different frequencies, and with DSP xovers like the Behringer DCX2496 also other slopes and types (LR, butterworth, bessel). To build a DIY active monitor using DCX is rather simple - just get decent drivers, use WinISD to design the box, put the drivers there with some stuffing, connect amps and DCX and start tuning. In addition it's best to have some kind of measurement mic (ecm8000 etc.), download the free speakerworkshop from http://www.speakerworkshop.com/ and use that to make MLS measurements for FR (nearfield, alt. take your spekers out under the blue sky and use the sine sweep which is more accurate). With the DCX you can also time-align the drivers easily, just connect the mic to input C, select SHORT DELAY and do the AUTOALIGN (read the manual).
DCX is pretty cheap these days (about 250 EUR). Some folks @diyaudio.com have modded it (changed opamps etc.).

Anyway, I don't know if it's improvement or not. If you have a passive speaker that's working fine and good amp then it may not be a big improvement if it's already perfectly tuned. Maybe bigger improvement comes by tuning the room.

 

[Kev]

yep

Maybe bigger improvement comes by tuning the room.

never underestimate the value of this
both recording room and listening room

The Active DSP units like the B unit are a great way to experiment and learn about the drivers themselves and the way there interact in a system.

This knowledge can be taken to the Passive Design stage so to tweak to the best possible ... and them some.
Tweaking passive designs are still very artfull and lots of experience is required.
This is a small group of components that all interact in so many subtle ways.

The B unit can get you to good combinations of drivers very quickly.
Fo some it may be enough to just stay and use the B unit full time.
... and there are other active DSP units on the market both with and without computer interfaces.

lots of fun

 

[PatinaCreme]

It is going to take me some time to save the $$ for this.

just for the sake of learning anyone else have nay ideas?


Patina

 

[PatinaCreme]

Gus you stated:
I don't like MDF I tend to like good plywood and carefull bracing

From what I have been reading everyone talks about MDF. I am interested in why you like plywood?



over and out
p

 

[tony dB]

and if you go for plywood, do you find the quality you need at the local woodstore? Very often the quality is insufficient and will strings of fiber rattle inside the boxes you build (had this with some 4X12" btw). MDF avoids this all and ads some pretty heavy mass as well, please tell us your plywood findings

Tony

 

[Marik]

Long gone topic...

I have three options and a lot of questions, if somebody could answer... Just cannot decide what I want, so need some fresh look from outside.

Right now I am trying to decide what close field monitors to have.
At present I am working with Jordan monitors--4" woofers. If you know the Jordans, it is pretty freaky staff. The woofer's x-max is about probably at least 7-8 mm. They are quite accurate, however I feel they are little bit too "musical". With some body dampening they are much closer to what I want them as monitors.
However, I still think the bass could go deeper.

Many years ago I wanted to try D'Appolito configuration, and out of 2" MDF I built enclosures for 5 1/2" woofers. I had in mind treated paper cone Audaxes. I built the enclosures, but never even got the drivers. The question:

I never had chance to listen to D'Appolitos, so what your impressions about it compare to conventional 2 driver design? I understand, it is hard to answer, as for the fair comparison many factors need to be matched. But anyway, anybody?

My dilemma is like this: for tweeters I could use ribbons I built, or as an alternative, my favorite Heil air motion trasformers. I also have a Rane 22 crossover with upgraded signal chain capacitors, and set of two amplifiers... and lots of MDF and wood.

I'd like to stay within $200--$250 max budget for woofers and my choices are:

1) For $160 to get four 5 1/2" Audaxes once I had in mind, and using the ribbon or Heil staff for tweeters, with my already built enclosure, to finish D'Appolito.

2) For around $250 to get a nice pair of 6,5-7" woofers, and together with my ribbon/Heil to design a new box?

On the other hand, is the D'Appolito so much superior? Should I wait to save some more $$$ and build something like a Thor with Seas drivers from Madisound?

The scary staff is that often the more expensive staff does not necessarily mean a better quality.

Either way, it will be biamped, with electronic crossover, for easy tweaking.

Oh my!!! I almost sound like on homerecording.com: "What would be the best mic for under $100".

 

[mhelin]

Problems with the D'Appolito are the vertical directivity and small sweet spot. I don't think it's good in nearfield listening, integration will be problem. Jordans and other full-ranges are great in that sense. Maybe you need just a subwoofer?

Also you could build your D'Appolites but eventually use them as 2 1/2 way speakers like here: http://home.hetnet.nl/~geenius/Proteus.html

 

[chrissugar]

Mhelin's link is an atempt to copy the Wilson Audio Cub loudspeaker.
http://www.wilsonaudio.com/products/cub/index.html
The coincidence is that I listened all this afternoon to a pair of Wilson Cubs, and I think these speakers are absolutely incredible. The resolution, dynamics and definition of space is amasing. I don't think there is any directivity and small sweet spot problem.
Unfortunately very expensive, but it looks like I can buy them for under half of the original price. :grin:

chrissugar

 

[Kev]

Wilson Audio

JLM Audio

looks like more than one person thinks this style of woof/mid looks cool
but phase plugs can be tricky

then get your choice of tweeter
and you are nearly there
:roll:
it's this next step that can really make the difference,
Wilson Audio went passive ... I think
and
JLM chose active.

 

[chrissugar]

Yes Kev,

The Wilsons are passive.
Joe's monitors have similar Focal tweeters.

chrissugar

 

[Bauman]

I wish I could afford those monitors from Joe...

 

[Marik]

[quote author="chrissugar"]Mhelin's link is an atempt to copy the Wilson Audio Cub loudspeaker.
http://www.wilsonaudio.com/products/cub/index.html
[/quote]

These guys are just about 30 miles down the road from me. I might probably take a ride there to have a listen.