817 for Hifi (Stereo) a good choice?

**bermuda007** · October 20th, 2011, 05:53 PM

Hi

I really need some advice. I have a Iwata 300 Horn (Radian 950 PB) which can go down to 500hz and i am thinking about to drive them with a original but new 817 cabinet with 4pcs GPA 515 LF (which i own allready). I would like to get your opinion, advises what you think about this ensemble. I know that i will not get the most deeply bass but i hope to reach between 50 or 70hz (vented?). What do you think?

Thanks a lot
bermuda

**Steve Mac** · October 20th, 2011, 08:09 PM

I really like dual 515 ideas and the 817 is a great cabinet for sure.
So I can say with a good deal of certainty you are going down a "no lose" pathway.

I know they made several variations and I'm sure others can help fill in those blanks.
Another idea is to pick the brains of the gurus on this board about potential improvements
especially as it is geared for home use. I can tell ya that parallel walls are to be avoided.

Regards, Steve

**bermuda007** · October 20th, 2011, 11:51 PM

Hi Steve
Thanks a lot for answering

Can you explain (pictures?) exactly what you mean about to avoid the parallel walls? Do you mean the the walls from the vented part of the cabinet?
Again thanks a lot for your kind help...

**Steve Mac** · October 21st, 2011, 03:38 PM

Originally Posted by bermuda007

Hi Steve
Thanks a lot for answering

Can you explain (pictures?) exactly what you mean about to avoid the parallel walls? Do you mean the the walls from the vented part of the cabinet?

You're welcome!
If you can grab hold of their ears, "Mr." GM is brilliant when it comes to cabinet "thinking", and well so are Old Guy, panomaniac...etc..there are many! Suffice to say, from a theoretical vantage point, they are founts of wisdom.

Here's a link which shows the horn of the cabinet design for a project I built...with help from the overlords here:
http://www.superbadcat.com/midBassDesign/horn2.gif
Actually it's the mid bass exterior walls I was referring...I think the upper and lower on the 817's are parallel?
In the design link I worked on, I stripped out the reflex altogether. And then added true horn loaded subs below 80Hz.

**bermuda007** · October 21st, 2011, 05:00 PM

Hi Steve
Your project looks amazing and now i understand what you mean. Is it possible to get the measures from your speaker. It looks yery interesting. What kind of driver do you use for them? 515? Have you allready built them?b

Thanks a lot

**bermuda007** · October 21st, 2011, 06:29 PM

i forgott....
what is exactly the issue with parallel wall?

**bermuda007** · October 22nd, 2011, 10:42 AM

So guys..
I was looking a bit around and i found a very interesting alternative for my 4pcs 515LF. What do you think about the famous "Onken W" (2x15'). It seems to be very exactly that what i am looking for...Ok, the WAF factor isn't that big but i guess 2 handbags and a nice dinner could do the work..

What do you meanabout Onken W ?
Thanks a lot

GM · October 22nd, 2011, 11:39 AM

Hmm, don't see anything about the 'W' in this thread. Regardless, it's a simple bass reflex that relies on a too small a vent area [Av] to preload it with its 'claim to fame' being a sand filled dual wall construction which IMO is a waste of time/$$ as a much lighter [though still heavy], well braced 3/4" [19 mm]/11-13 ply Baltic Birch or Apple ply plywood cab will be at least as sonically inert or probably even more so if tuned lower than the 'W' since its Fs will be well above its pass-band rather than just pushed down to near/at its lower response corner [F3], ergo there's no signal strong enough to excite it. If you want overkill and/or use less bracing, use 1" [25.4 mm] thick, at least for the baffle.

Anyway, at this net bulk, some form of TL is a better choice overall IMO.

GM

**bermuda007** · October 23rd, 2011, 02:12 AM

Thanks again GM.

In the meantime i got a advice from Bill from GPA. He said that he would go for a 6cubicf with a 5' diameter vented cabinet. It goes down to approx 35hz with good mids (not as loud as with horns). He said also that he don't like bass horn cabinets for home use because the horn loading is good down to about 100hz then the horn cuts off and the box is a vented type (817), the speaker will produce bass below horn cut off but it will a lot lower in amplitude compared to the horns output, so it will sound like the low bass is weak.

So i got the answer. I have 4pcs of 515 and i will use only 2 of them...my mistake! I will check out this with my cabinet maker. Does anyone have plans for a 6cubicf cabinet (with 5' diameter)? This would be great!
Thanks to all for helping me on this project.
Regards
Bermuda

GM · October 23rd, 2011, 11:37 PM

You're welcome!

Different strokes.......... While I agree that without a separate sub system, the 817s leave a lot to be desired for HIFI/HT, only using singles when you already have doubles is going in the wrong direction IMO. I've run singles, but it takes dual 515s in large cabs tuned to at least Fs to do justice to most music and tuned down around 16 Hz for the few pipe organ symphonies and most movie soundtracks at reference; or if this is too loud, then at least can be driven with a SET amp for best overall low distortion SQ.

GM