1801F

David Ellis · « **Reply #40 on:** 25 Aug 2004, 09:40 pm »

Our ears agree about the bass, but I think it's more of a difference than a "winner". Dennis thought the bass from the stand mounted 1801 had more "authority" than the 1801F. I agree, but thought the 1801F had slightly deeper/more natural bass. This was using the same length port in both cabinets.

Since the cabinet of the 1801F is slightly larger, the port should be slightly shorter. Making the 1801F port shorter will make the bass more boomy. I can hear changes when removing 1/2" of material from the port length.

salva · « **Reply #41 on:** 30 Aug 2004, 09:16 pm »

A couple of photos more, all the fittings placed, and grille added. Hope you like them.

Salva

smithsonga · « **Reply #42 on:** 30 Aug 2004, 11:40 pm »

great pics.

How did you construct and attach the grills?

David Ellis · « **Reply #43 on:** 31 Aug 2004, 02:40 am »

This is a very decent picture of John's speakers:

salva · « **Reply #44 on:** 31 Aug 2004, 06:31 pm »

Hi, just a small remark .. after a couple of days of runnig the 1801f's with spikes I have to say that the Bass seems to be more "deep" and contundent.

Besides the obius fact that they look better and can be leveled

Salva

David Ellis · « **Reply #45 on:** 31 Aug 2004, 10:22 pm »

I agree with you about the bass, but think this difference is quite small. How significant is the change in bass between the 1801 and 1801F?

I thought the difference was present and preferred the 1801F bass. Doc Murphy kinda' liked the bass from the stand-mounted 1801.

salva · « **Reply #46 on:** 3 Sep 2004, 12:53 pm »

Yeah, I meant bass was different after fitting spikes in the 1801F

More "deep" is my impression. Floor is solid barble.

So it makes sense to fit the spikes in my case. (besides the appaerance factor).

Salva

ultrachrome · « **Reply #47 on:** 4 Oct 2004, 09:45 pm »

I used "cleaning out the garage" as an excuse to cut the pieces for the F version. Had to do something about that 4x8 sheet of MDF that was clogging up the garage.

However, in my haste I didn't end up with the quality I hoped for. Didn't repeat the mistakes from my stand mounted cabinets, instead making new ones.

Not having time to build another set of cabinets and not wanting to live with plain MDF boxes, I tried aerosol bed liner and it came out really well. Used two cans but really need a third as I ran the second dry on the second coat. I think the finish really compliments the drivers.

David Ellis · « **Reply #48 on:** 4 Oct 2004, 11:18 pm »

I think that look is very nice too. Sure, it's not a rich wood finish, but very practical and very durable. This is a very smart move IMO. Please share more

What kind of bed liner did you use and what did you put under the bed liner for a primer? Did you use a primer.

How did you mange the driver recess with the finish thickness? Did you simply cut the recess slightly large to accomodate the bed-liner build?

This is the kind of DIY I think is really great. Those cabinets look fairly decent, and were soooo much easier/quicker than veneer cabinets with rubbed lacquer!

ultrachrome · « **Reply #49 on:** 4 Oct 2004, 11:55 pm »

I used Duplicolor brand that I picked up for about $8 a can at the local autoparts chain. You can buy it in can for rolling but that was a bit more investment.

I basically bowed my front baffle from clamping the top and bottom with too much force using a racheting tie-down strap. I thought veneer might make this flaw too apparent so I rushed to finish them.

I wish I had bothered to prime because there is some photographing on the top where the edges of the front/sides is obvious. I didn't expect to like the finish as much as I do.

The finish isn't very thick. I first hit the driver openings with some black spray paint and kept the bedliner spray direction perpendicular to the front so to avoid getting excess paint on the sides of the rebate. So no clearance problems.

Ron Stewart · « **Reply #50 on:** 17 Oct 2004, 09:00 pm »

Hello everybody. This is my first AudioCircle post, so I hope it ends up where I want, at the end of the big 1801F/1801BF thread.

I'm seriously considering building a pair of 1801BF's. I'd like to build the cabinets first. If I'm successful, and the cabinets look good enough to warrant a place in our family room, I'll order the kit and install the drivers and crossover. If I fail, I'm only out some time and the cost of the MDF.

I've drawn a pretty detailed set of plans: http://home.hiwaay.net/~rgs/ellis1801bf/Ellis1801BF.html.

I'm pretty sure I have the overall dimensions correct, but I have a few questions that I hope one of you can answer.

(1) Are the driver cutout dimensions correct?
(2) Is that port tube hole diameter correct?
(3) Can the crossover be build in such a way that it will fit on a 5" wide access panel?
(4) Due to the narrow width of the inner front panel, it's not possible to round over the inside of the driver hole. Do you guys round over or scallop what you can, or do you just leave the hole alone after you cut it?

I would also be interested in hearing any comments about these plans, or suggestions for improvement. Thanks.

Ron Stewart

salva · « **Reply #51 on:** 18 Oct 2004, 07:26 pm »

My experience after having done a 1801b and a 1801F

Details on the first post should be enough, the photos will have to clear any doubts.

It worked for me and I'm very dumb

Ok, just a tip DON'T cut the driver holes without the drivers or the port, one milimiter error can potentially cause a big mess. The way I did was doing a test hole on a spare lumber and test if the cutting jig is OK, then and only then cut the real hole.

Yes, I did the xover around 5" witdh, it is just screwed to the back pannel.

It is true, I did not scallop the inner driver hole, there was no space to do it. I guess is not a mayor issue.

Just my two cents.

Salva

ultrachrome · « **Reply #52 on:** 18 Oct 2004, 08:47 pm »

If you follow Dave's crossover assembly instructions, it will fit very easily. Make sure your brace has plenty of open room behind the driver so your crossover can be easily positioned on the back panel.

For my brace, I cut square holes with 1.25" radiused corners. For me it was faster using a spade bit and a jig saw. I then rounded over the edges which is a must for making crossover mounting/wiring as painless as possible.

I pretty much mirrored the construction of the normal cabinet by assembling the top/bottom and front/brace/rear. Then I mounted and trimmed sides, followed by mounting and trimming of second front panel.

Ron Stewart · « **Reply #53 on:** 19 Oct 2004, 01:19 am »

Salva, ultrachrome,

Thanks for responding. Your posts raise a few more questions.

I suppose I can understand how cutting the port hole a mm or two too wide could be a big problem (a loose fitting port and air leakage). How bad is that sort of error on the woofer or tweeter cutouts/recesses? For example, if the woofer recess diameter is 2 mm too big, will that really cause a problem (other than not looking as pretty as perfect fit)? Or were you referring to errors in the recess depth?

Salva, you said attached your crossover board to the rear panel. Did you attach it before assembly, or did you insert it through the woofer hole, and through one of the circular holes, in the center brace like ultrachrome did? Based on your drawings, I wasn't sure the board would fit through any of the brace holes.

Regarding square vs. round brace holes, I suppose the different internal cabinet volumes resulting from different shaped/sized holes is negligible? I've wondered if my idea of mounting the crossover on a removable panel was overkill. (I'll probably still try it anyway.)

Ron

David Ellis · « **Reply #54 on:** 19 Oct 2004, 02:06 am »

Thanks for the big contibutiuon with the CAD drawings. I experimented with this, and CAD simply consumed way too much time. I found pictures much more beneficial. I will comment as necessary.

Quote

(1) Are the driver cutout dimensions correct?

Yep, they are generally correct, but I agree with Salva regarding this issue. Don't cut the driver holes unless the actual drivers are present for a test recess. A measuring tape simply is not accurate enough to obtain an aesthetically acceptable tolerance with the driver recess. I tried this a few times and failed. I cut one recess too big and the other too small.

Quote

(2) Is that port tube hole diameter correct?

Yep, 2 1/8" is what I use.

Quote

(3) Can the crossover be build in such a way that it will fit on a 5" wide access panel?

Yep, 5" is the size of a narrow crossover board. This eliminates the need for an access panel in the rear of the cabinet as drawn via CAD. Also, the top hole behind the woofer must be slightly larger to accomodate the 5" wide crossover board.

Quote

(4) Due to the narrow width of the inner front panel, it's not possible to round over the inside of the driver hole. Do you guys round over or scallop what you can, or do you just leave the hole alone after you cut it?

Removing the driver tunnel is a good idea, but obviously it's not always possible. I recommend opening the driver tunnel with scallops or a taper on the top and bottom in this cabinet. The sides obviously don't allow much room for a taper. The concept is to eliminate the tunnel resonance created by the round tunnel. I think eliminating some material from the top & bottom of the tunnel works fine.

Your work and drawings are excellent. Thanks again for your very good work!

Sincerely,

[/quote]

rmihai0 · « **Reply #55 on:** 25 Oct 2004, 04:11 pm »

Dear Ellis,

I am following your work with great interest for almost one year now. Great job. I want to ask you coupl of questions:
- when do you think that you will have time (if interested) to launch a 3-way kit
- what do you think about using Great Heils for highs and some mids?
- what do you think about having the crossovers at 800 hz and 1600 hz for this kind of design?

Anyhow I am waiting to get one of yours firsts 3-ways kits with GREAT interest.

David Ellis · « **Reply #56 on:** 26 Oct 2004, 12:08 am »

I posted your response in the appropriate string here:

http://www.audiocircle.com/index.php?topic=7739&postdays=0&postorder=asc&start=40

salva · « **Reply #57 on:** 1 Nov 2004, 01:13 pm »

Hi, on the 1801F's that I did after a couple of months I have the impression that they are very lean, I will like a more "boomy" sound.

Yesterday I was comparing the 1801F vs 1801b, both with Dave's standard supplied port, the difference was huge in favor of the 1801b.

So, I guess that I will have to shorten the port.

Has ppl experimented tuning the 1801F BR port ?

If so, how much you have cutted from the standard port supplied by Dave ?

Salva

salva · « **Reply #58 on:** 1 Nov 2004, 08:11 pm »

HI there, after a complete afternoon of tests, in the small room I have being doing the tests and were the speakers are fitted, the best performance was no BR port fitted at all. Only the hole.

What do you think ?

I've left it like that and I will see how it goes, perhaps the sound is too "boomy" but before it was to lean. I will live with it for a while and decide on that.

Salva

David Ellis · « **Reply #59 on:** 2 Nov 2004, 03:47 am »

Salva,

You probably have several extra ports. I generally send these for experimentation. I suggest you remove port length in 1/2" increments for experimentation.

The ports in my 1801F speakers remain full length.

Dave