HiVi Drivers

[meb46]

Hello all,

I'm new to this forum but are hoping someone out there can help me out with a question on HiVi Drivers and Speaker confirguration.

I am interested to know of anyone using HiVi drivers and what sort of impressions people have of them.

I am midst way through building some rather large 4-way multi enclosure speakers and I have selected a number of the HiVi Drivers as part of my design. I am not wanting to change from these drivers at this late stage, but interested to know of peoples experience.

Each speaker is separated into 3 separate enclosures, two of the enclosures house 2x D10.8 Woofers in a Base Reflex configuration, and then the third cabinet houses 2x D6.8 Mid-Base + 2x DMN-A Mid and 2x T28 Tweeters. Obviously serious overkill but an interesting project none the less The three cabinets are stacked vertically with the Mid-Base cabinet in the middle. All speakers are vertically symmetrical.

My second question comes with respect to the alignment of the drivers in the middle enclosure (Mid Base/Mid/Treble). Due to the drivers and overall size of things, I am unable to vertically align the mid/treble speakers. At the moemnt I have these off set with one side of the mid-cabinet has the 2x 6" drivers verically aligned and then on the other side of the cabinet I have the DMN-A vertically opposed with 2x T28 tweeters in between. I am concerned with the Tubing of this alignment and am considering dropping one of the tweeters. The left and right channels are opposed and my cross overs are fairly accurate in the frequency separation between drivers so there isnt a massive amount of over lap.

Let me know if you have any feedback or experience with these drivers or can comment on the alignment queries.

Much appreciated.

[---k---]

Jon Marsh, our fearless leader, has used the D6.8 a couple of times. Lots of info in his NeoD CC thread:

http://htguide.com/forum/showthread.php4?t=27218

I would definitely drop the dual tweeters and read up on Comb Filtering.

[JonMarsh]

I also have experience with the M8a and M6a, but that's not relevant in this case.

I'm guessing you have measurement equipment and design experience- keep us posted on how things turn out. The D6.8 is pretty solid in the 100 Hz to 1500 Hz area, and easy to work with, shouldn't have any problems. It can go moderately low as a complete mid woofer, with a nice bottom end, but with the 10" HiVi, you won't need to worry.

[meb46]

Thanks for the input guys, very much appreciated.

I think I will drop one of the tweeters as noted, but still a little concerned with the actual configuration of the Mid/Treble enclosure. I intend on getting one of these pinned together over the weekend, so I will post some pictures shortly.

Cheers

[meb46]

A few pictures of progress thus far...

Please note, I think I will remove one of the 1" tweeters from the mid cabinet, but I am still a little concerned about the overall configuration of the mid-cabinet. I couldn't stack all drivers vertically as I simply run out of vertical height... obviously with 4x 10" woofers, these do become very large

[---k---]

Wow, looks like very nice cabinets. How are you planning on designing your crossovers?

[chasw98]

If you don't mind.... Who or where did you get the CNC machining done? And I am curious why you did not have the holes for the drivers routed out so that the drivers would sit flush when you mount them in the cabinets? Looks like a very interesting project. Depending upon how you can manipulate the bass bins, you might consider an active 2 way xover for the bottom end and passive for the md/hi cross. More pictures!

Chuck

[meb46]

The crossovers are my weak point and the area I think I will have the most experimentation with. I had the guys at Madisound develope and make the initial 4-way crossovers as shown in the attachments. These now have to be modified as they were initially designed for 2x 10" Woofers + 2x 6" Mid-Base + 2x 2" Mids + 2x 1" Tweeters... I have now changed the design to use 4x 10" Woofers, 2x 6" Mid-Base + 2x 2" Mids and only 1x 1" Tweeter. The configuration and selection of drivers is purely for experimentation, so I guess in the coming months I will soon determine if I have any success or if its been a bit of a waste of time... eitherway... I am getting a huge amount of enjoyment out of the process :-) . Any suggestions on the crossovers or modifications are welcome

The project idea came from a lost past time I hadn't been able to accomodate since I had moved to Singapore, and the time had come to start playing again. Two ideas I have wanted to explore for some time is curved sides and the use of CNC routing.

The curved sides were the biggest hurdle which I have now managed to overcome by ways of custom 25mm pressed panels from China. My job sees me travelling a lot from Singapore through-out Asia and one of the perks is that I spend a great deal of time at Electronics Trade shows... hence lots of informal chats with Chinese Speaker manufacturers. One company I found managed to make a 760mm curved panel press tool for me to make the side panels. The first off tool sample is due to arrive in the next few dayy so I will take some pictures then. Progress so far looks positive, so the first sample will be the true answer In the name of cost, these are 25mm thic pressed Plywood, NOT 25mm MDF Curved Panels. The difference is over 10x... hence Plywood won the fight! These are still pretty dense, with each side panel for the base cabinet weighing nearly 10kg... according to the manufacturer.

The CNC routing was a necessity due to the curved sides. As soon as I had decided I needed the routing for the sides I added into the design internal machined ribs for support and bracing. The company I used is a local (to me in Singapore) sign maker. They use their router to cut massive signs for shops etc. I simply sent through the CAD/3D Models of each of the panels and they machined them all out for me over a few days out of 25mm MDF. It's NOT a cheap way to make speakers,but the accuracy and finish is exceptional. The panels are cut to less than 0.3mm tolerance and all panels fit together perfectly. The joys of 3D modelling and CNC machining is fantastic. It makes things simply "easy" to put together. My previous speaker building projects were limited to basic rectangluar flush cut/joined cabinets excluding my Klipsch-Horn's, but I will never revert back. CNC routing and cutting just makes things so much easier. It's definitely worth investing in developing ones CAD and Solid Works skills to aid in a hobby like this one

The cabinets will eventually be veneered and after this process I will route into the veneer and front baffle the recess for the speakers to mount flush. This way is easier to ensure the veneer has a clean finish on the front baffle, and then I can ensure the route and flush mount is perfect. After it has this machined into it, the cabinets will be sprayed with a clear piano gloss finish (yet to find a local supplier for this stage).

At present I have just started to reinforce all of the internal joints of the speakers with 50mm Fibreglass Tape which I will then epoxy over. They are going to be heavy and since all three cabinets are stacked vertically I need to ensure they have maximum bracing and strength. The fibre glass process is very messy and does detract from the overall look of the construction, but it is necessary for strength. It also enables me to guarantee things are sealled perfectly.

Will post some pictures in the coming days.

[meb46]

Progress up-date... things progressing very slowly. the size of these things and what I thought were quick easy task's are all taking serious time. Thus far I have managed to get one side progressed to the point of wiring and cabinet preparation for veneer. The Cross-over cabling is in progress, but still to be finalized. The most time consuming part was cutting and fitting the bitumen lining and the foam lining.

The pressed side panels arrived and were a little warped. My intended method of fitting these had to be altered, so I am now using strops and clamps to hold the panels on whilst gluing. The first bass cabinet was a little messy, but the second one has bone together well.

Fingers crossed things progress a little faster now

[meb46]

Further photos...

[meb46]

Last installment for the night...

[BOBinGA]

Those curved sides look great. Looks like a good tight fit with your internal bracing. Maybe you should consider exporting those to use here in the States now that you have the manufacturing contacts.

-Bob

[foxes_lover]

Hi Meb46,
How did the project end? Did the DMN-A dome mid work well? I'm planning to build a 4-5 way speaker using Hivi drivers but not sure about Hivi' dome mid driver.
Thank you.