HiVi Juniors Project

[Sillyboy]

Hi folks. First time poster here, thanks for all the sweet info on this forum

As a complete n00b, I naturally have at least 27 trillion questions, but i am going to avoid hitting you with them all at once

My goal is to create a pair of small'ish speakers to use 80% television, 20% music. The "smallish" mostly has to do with WAF, as currently we have 2" cubes that she finds cute I suppose -- I find them awful. I am going to worry about a sub at some other point.

I am thinking of a 2-way speaker with 4" woofer. In looking at parts express I came across the HiVi Juniors project (http://www.partsexpress.com/projects...rs/design.html) and have a few questions:

1) anybody made those and have feedback?

2) according to Zaph (hi man, love your site) :

I will never vent a woofer that is 4" or smaller. I've seen many people that do however. The problem with that is the tuning frequency will be too high, and there will always be substantial music output below the tuning frequency, easily distorting or destroying the woofer.

As a n00b, I can only vaguely understand what that means, but the HiVi Junior design is for a ported box... should I modify the design to not use a port?

3) From the plans:

I modeled the B4N woofers in BassBox Pro and came up with a 0.16 cu.ft box.

Errrr, okay... but according to http://www.partsexpress.com/resource.../sb_guide.html the "Vented Volume cu.ft." is .30 ft. What gives?

4) According to that page, vented boxes should have *more* volume? That seems counter-intuitive. So either I am miss understanding that data, or need a thought adjustment. To me, it seems like a port would allow the speaker to "move" more easily and thus doesn't need as much air space.

5) Trying to use WinISD to calculate the volume myself was somewhat hopeless. I added a new speaker with stats from parts express: Qes(.63) Qms(3.91) Qts(0.52) Fs(56) Vas(.16 ft^3). Hitting save, I get a consistency failure. If I delete Qms... it "calculates" it at 2.978, then I can save --- but uhh... that is not the stat parts express gave. <sigh>. Any idea? And do I need to enter any other data?

6) I don't want to get toooo into crossovers at this point, cuz as a n00b its the scariest part and I am not mentally prepared, but a few minor things:

- According to http://www.partsexpress.com/pdf/297-429.pdf the Hi-Vi B4N has a serious spike at 3k. Don't we need to cross over at some point before that then?

- On the other hand, the chart at http://www.partsexpress.com/pdf/297-429g.pdf looks quite a bit different (no huge spike) -- which makes it challenging to know what to believe So... How do *I* get a fancy chart like those (or from the project site http://www.partsexpress.com/projects...iors/graph.jpg)? I like them, since it's something very "understandable" to the n00bs -- "I want to measure it and make that line flat as possible". Can I just throw my computer mic in front of the speaker and run some funky free software?

I am super excited about building my first speakers, and hope the experts here can make it a worthwhile experience. Apologies for hitting you guys with 7'ish questions right out of the gate, but hopefully they aren't retarded Thanks in advance.

-Sillyboy

[noodle_snacks]

Originally posted by Sillyboy
Hi folks. First time poster here, thanks for all the sweet info on this forum

As a complete n00b, I naturally have at least 27 trillion questions, but i am going to avoid hitting you with them all at once

My goal is to create a pair of small'ish speakers to use 80% television, 20% music. The "smallish" mostly has to do with WAF, as currently we have 2" cubes that she finds cute I suppose -- I find them awful. I am going to worry about a sub at some other point.

I am thinking of a 2-way speaker with 4" woofer. In looking at parts express I came across the HiVi Juniors project (http://www.partsexpress.com/projects...rs/design.html) and have a few questions:

1) anybody made those and have feedback?

Can't Say I have

2) according to Zaph (hi man, love your site) :
As a n00b, I can only vaguely understand what that means, but the HiVi Junior design is for a ported box... should I modify the design to not use a port?

Below the tuning point of a ported speaker power handling decreases very rapidly. These speakers will not handle much power below 60hz (This is not so much of an issue if you will be building a sub).

3) From the plans:

Errrr, okay... but according to http://www.partsexpress.com/resource.../sb_guide.html the "Vented Volume cu.ft." is .30 ft. What gives?

The suggested vented volume there is probably a different alignment. You could try using winISD and simulating different enclosures for yourself (look at amplitude response, and cone excursion for a given power input)

4) According to that page, vented boxes should have *more* volume? That seems counter-intuitive. So either I am miss understanding that data, or need a thought adjustment. To me, it seems like a port would allow the speaker to "move" more easily and thus doesn't need as much air space.

http://en.wikipedia.org/wiki/Bass_reflex

Might give a decent description of how a vented box works.

5) Trying to use WinISD to calculate the volume myself was somewhat hopeless. I added a new speaker with stats from parts express: Qes(.63) Qms(3.91) Qts(0.52) Fs(56) Vas(.16 ft^3). Hitting save, I get a consistency failure. If I delete Qms... it "calculates" it at 2.978, then I can save --- but uhh... that is not the stat parts express gave. <sigh>. Any idea? And do I need to enter any other data?

Try deleting other parameters such as Qes or Qts, often in doing so i can get closer results, as long as the parameters are reasonably close i wouldn't worry

6) I don't want to get toooo into crossovers at this point, cuz as a n00b its the scariest part and I am not mentally prepared, but a few minor things:

- According to http://www.partsexpress.com/pdf/297-429.pdf the Hi-Vi B4N has a serious spike at 3k. Don't we need to cross over at some point before that then?

Depending on the slope of the crossover there is a region where the outputs from both drivers contribute to the total output of the system. That large peak would be addressed in the crossover with something called a notch filter (Without one a large, nasty peak would appear in the frequency response). Soft coned drivers, eg polypropelyne or paper do not have a peak like this and are simpler to crossover for a beginner.

- On the other hand, the chart at http://www.partsexpress.com/pdf/297-429g.pdf looks quite a bit different (no huge spike) -- which makes it challenging to know what to believe So... How do *I* get a fancy chart like those (or from the project site http://www.partsexpress.com/projects...iors/graph.jpg)? I like them, since it's something very "understandable" to the n00bs -- "I want to measure it and make that line flat as possible". Can I just throw my computer mic in front of the speaker and run some funky free software?

The peak is still there, different scaling and smoothing has been used to give that chart, thats why it looks a bit different. It would not be difficult to get a chart of your own similar to those, your pc microphone is probably not suitably accurate however. To take acoustic measurements you will need a microphone (the behringer ECM 8000 is an inexpensive example) and a microphone preamp with phantom power (the behringer UB802 would be another example). Then you can use speaker workshop:

http://www.audua.com/

If you wish to take this path i would also consider reading the unofficial manual (Warning it is 18mb):

http://www.audiodiycentral.com/resou...anual/SWM2.zip

I am super excited about building my first speakers, and hope the experts here can make it a worthwhile experience. Apologies for hitting you guys with 7'ish questions right out of the gate, but hopefully they aren't retarded Thanks in advance.

I'd go for a proven design first, and you might be able to get some more direction if you give budget and size requirements.

-Sillyboy

[sreten]

Hi,

http://www.zaphaudio.com/audio-speaker19.html

I think you'd be a lot better off with the above than the Juniors.
The Juniors crossover does not seem to implement any BSC.

Regarding your questions :

1) no comment.

2) Yes and No. Use a 5" driver sealed in the same box volume.

3) For a driver reflex box volume is ~ 2 x sealed box volume.

4) & 5) no comment.

6) Too true - don't get involved in crossovers unless you are sure.
Zaphs 19 has a far more developed crossover than the Junior.

Zaphs 19 will work fine in a sealed stuffed 3 to 4.5 litre box.
In fact the recommended 0.25 cuft box is really too large IMO
for sealed loading and is only needed for a reflex alignment.

/sreten.

[Sillyboy]

Thanks for your reply noodle.

Below the tuning point of a ported speaker power handling decreases very rapidly. These speakers will not handle much power below 60hz (This is not so much of an issue if you will be building a sub).

I am not super sure what "power handling" is, but my guess is this: with equivalent power (does this equate directly to volume?) compared to a sealed box... a ported box will cause the speaker to extend farther (at low frequencies), possibly "too far", which could harm the speaker.

That sounds mostly understandable. How does that translate from the theoretical to reality? These speakers are rated at 25 watts RMS, so... with a port, I would have to drive them with... "less" ? Is harming the speaker the only real concern here (I am guessing the designer of this project isn't having any "problems", so I am still stuggling to understand if porting this box was a "bad idea").

re: WinISD -- its really kicking my butt. I can not for the life of me get a volume any NEAR what the project suggests. And I am too n00b to know what "close enough" is in terms of entering the driver params. I would really appreciate it if someone else could try and model this driver. Entering the Q params is problematic for me: Qes(.63) Qms(3.91) Qts(0.52) are the values from parts express, but WinISD wants something like Qes(.63) Qms(2.978) w/ the Qms auto calculated. No idea if 2.978 is close to 3.91.

re: spike at 3k, I don't *think* there was a notch filter in the cross over design from the project, but someone else would have to confirm that. At a minimum, you agree that this is "problematic"

re: measuring equipment.. yikes! Looks like I am spending $50 on a mic, and $60 on a pre-amp? Brutal. But most people who build speakers do this I assume?

re: a proven design: that is probably a good idea However, I really want to dig into this and understand the details, too. If I just follow plans or build a kit, all that I have learned is that I can follow directions.

Thanks a ton for your help.

[Sillyboy]

Oops, and meant to clarify my goals:

Cheap: maybe $150 max for the pair.
Small: maybe .15 ft^3 (do most peoplen talk liters?)

And naturally sound pretty decent I will likely need to live with them for awhile with a sub, so the more bass the merrier, but given the size I realize there is only so much that can be done. Especially since adding a port (to get more bass) will apparently also require a larger enclosure.

And ya, I have looked at Zaph's #19 -- but I fear the wife will hurt me. These speakers are going to fit on small stands next to the tv (which currently hold tiny cubes), WAF goes down w/ each cubic foot...

Thanks again.

[Sillyboy]

Sorry, can't figure out how to edit a post (is that possible?).

I obviously meant: I will likely need to live with them for awhile without a sub...

[gary f]

I suggest the Hatt III from Tony Gee

http://www.humblehomemadehifi.com/

I have a speaker similar to hatt-SE with excel W12 4 inch woofer. The sound is excellent and I listen to it without subwoofer since 2 years, no problems here.

Hatt III use the L12, you should get enough bass also. The size is quite small.

F

[Cal Weldon]

Siilyboy,

There is an edit button at the bottom of each window that you posted. It is active for about 1/2 hour after the original post. If you ever have a real oops after it times out, you can contact the mods and we can edit it for you.

[toque_101]

Hi Sillyboy,

The HATT III looks very nice, but it may be a bit beyond your price point. There is another small kit that I have heard good things about from a few people. The North Creek Echo is $149 for the kit:

http://www.northcreekmusic.com/Echo/EchoInfo.htm

The nice thing is, you buy the kit and they send you literally everything except the wood and glue. It's nice because you avoid a lot of the hidden expenses you don't plan for.

-steve

[Sillyboy]

Is it my imagination or does everyone think I should clearly start with a kit (or at a minimum a known good project) ?

I suppose I could do that... just not sure how much it will grow my knowledge. Feels like copying someone's math homework (which once you understand is certainly a swell idea, but before then... probably not so good ).

Project/Kit recommendations have been coming in the form of 4.5-5" woofers, I am gonna make a hard stand on a 4", as that is already going to make the wife a big grumpy.

And given that sealed volumes are apparently about half that of ported, I am going to target a sealed box. (and clearly need to start working on that sub problem).

So, does anybody know of a good project design w/ a sealed enclosure and 4" woofer? Or... do we get to design our own?