AudioCircle
Other Stuff => Archived Manufacturer Circles => Ellis Audio => Topic started by: David Ellis on 19 Jan 2004, 04:27 am
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This section of my forum will address all things related to the 1801F. While this is a viable option for the 1801 components, I don't plan to develop an ornate set of cabinet plans for this cabinet option. Also, I don't plan on selling any completed speakers of this version. There are several reasons for this. My initial post here will address the tertiary backround for the 1801F. As this portal devlops, I encourage anyone to ask me questions pertaining to this project - really.
I fully realized that many folks seemed to want a floorstanding speaker. I also liked the look of a slim floorstanding speaker. The ProAc D15 was quite striking IMO, so I decided to build an 1801 version for testing. My initial results were favorable, but by a VERY small margin.
The 1801F bass seemed slightly better. I can attribute this effect to 2 (yes, bad english) possible causes. Both of these causes encompass port location. The port faces backwards at the very bottom of the cabinet. First, the distance between the port and driver is greater. This makes cancellations outside the tuning frequency more "difficult" because the front wave and the back wave must travel further to cancel. Second, the port is at ground level. This makes floor coupling much better. The initial wave and reflected wave are very close. This should make the bass cleaner. The overall result was more seamless bass, but the diffence was VERY slight.
The 1801F midrange seemed slightly worse. The midrange just wasn't as clear. Images didn't seem to float on air like the heavier 1801B with my 60lb stands. I believe the primary reason for this was my relatively weak experimental cabinet. The baffle was thin I'll seguay slighty and explain MY basic construction.
All exterior panels are built from 3/4" MDF and there is 1 vertical brace connecting the sides/top/bottom. The external dimensions are 40" tall x 7 1/2" wide x 10" deep. The tweeter is offset 1/2" and the flange is about 3/8" down from the top of the cabinet.
(http://www.ellisaudio.com/floorstander.jpg)
The lighting for this picture isn't the best, but it provides a general idea of the layout.
Anyhow, the front baffle on MY 1801F speakers is only 3/4" thick. Since the cabients were only for "fun", I didn't make the baffle thicker. I believe the thinner baffle is the reason for the slightly smeared midrange. As such, I recommend anyone building the 1801F to use a thicker baffle and adjust the cabinet depth appropriately. While 3/4" thick material might be acceptable for many hifi speakers, I am not fully convinced 3/4" thick baffles are adequate.
Again, I must mention these audible differences between the 1801b and 1801F (also a b), were extremely slightl. Dennis Murphy, Gary Ganser and I had the change to compare these speakers in Bethesda in the spring of 2003. The midrange differences were not audible (me included), and Dennis remarked that the bass from the 1801b (stand mounted) had a little more punch. I agree with Dennis on his assessment about the bass, and there is good reason for this.
The cabinet tuning of the 1801F was slightly lean for Doc's room. Since the 1801F cabinet is larger, it should have a proportionally shorter port. I am confident that with a shorter port bass differences would be minimized too.
So, this is a very long explanation to convey that the audible differences between the 1801B and 1801F are VERY small or non-existent.
My next post will be slightly shorter and encompass baffle differences.
Dave
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Dave, beautiful cabinets.
'Just for fun' I'd like to see you build a floorstander with a larger Seas driver. Or maybe an additional woofer. :)
Welcome back,
Randog
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Dave, these are truly nice looking. I had the opportunity and pleasure to audition your MTM prototype at Dennis place last year. That sounded really nice to me. I would guess the MTM vesion would sound better. With Dennis' know-how and genuineness in designing superb xovers, would there be a possibility to see the MTM floorstand getting fully developed? If MTM can sound better than this or even 1801b, I think it would be a great idea to take it up to the next notch. Just a thought!
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I have very certain thoughts on those matters, but I'll address those topics in a different thread. Things will be better organized this way.
My comments here will address the baffle differences between the 1801B and 1801BF. I think this will be how I describe the floorstander from this point forward. Calling it an "1801BF" migh eliminate some confusion.
Initially I was VERY paranoid :nono: about changing the baffle size of ANY speaker with the same crossover. I have recently learned that some changes are acceptable. I will first explain the issue of baffle step.
ALL drivers on ALL baffles incur baffle step. Baffle step is a 6db progressive loading on the driver. It effectively causes a driver that is 85db (based on T/S parameters) to be 91db as frequency rises. It generally starts around 200hz and is fully established by 1200hz. The size of the baffle effects when the baffle step begins and ends. It is a very serious issue. Failing to control baffle step results in a loudspeaker that sounds very thin due to frequency response imbalance. The upward slope of the response sounds forward and... ouch! Bigger baffles start&end their baffle step at lower hz, and smaller baffles start&end their baffle step at higher hz.
A crude way of understanding baffle step is comparing it to horn loading. The bottom end of a horns loading is determined by the size of the flange. The same is true with the baffle. The bottom end frequency of baffle loading is determined by the size of the baffle. Smaller baffles don't load very low. Larger baffles will load much lower.
Given the 1801B and 1801BF, I was very concerned the baffle loading would be an issue. It's not. I measured it & listened to it. The impact isn't present.
The other issue extant between the 1801B and 1801BF is the roundover at the edge of the baffle. The 1801BF has no roundover. It has sharp veneer edges. The impact is measurable, but not audible. Again, the impact is measurable, but not audible. The 1801BF has an on axis ripple round 8khz that swings + & - 3 db. This is very visible on the graph. This is quite striking to the eye, because most of the 1801 response varies about 1db - very flat. However, when the microphone is moved off axis just a scosh the ripple flattens. Hence, the impact of the sharp baffle edge is only present on axis.
On a personal note. I found this very interesting. It was very insightful, and laid to rest some marketing issues among many manufacurers concerning edge roundover. I often wondered how speakers like Dunlavy could sound decent with all of those sharp edges around the drivers. Surely the B&W nautilus midrange must have a very clear advantage. After some personal education with baffle edge diffraction effect I believe 2 things.
1. There is a positive aesthetic, measurable and theoretical impact of a nice baffle edge roundover.
2. It ain't audible.
Dave
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Hi Dave,
Welcome back! It's good to read your common sense approach to audio. Also, the F design looks very nice. I have a question regarding floor standing speakers. Have you ever tried a QW design similar to Dennis' "Bob" speakers? I heard a pair and was impressed by the bass output. Do you plan to test a "Bob" design for people who don't have the room for a large 3-way?
THanks!
Jack
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I have no plans to work on a TQWP version of the 1801.
And, sorry, we never chatted about this on the telephone.
Hearing the Veracity version of TQWP was enough for me. Sure it sounded a little better, but didn't have real bass.
When I consider building a speaker I consider several things.
1. Electronics Cost
2. Cabinet size/Aesthetics
3. Sound Quality
I then consider #1 and #2 after I ship the bugger. The net result is that a TQWP is a very bad move. It nets considerable cost, and very little gain for the end user.
I did some TQWP calculations. The cabinet you witnessed at the Iowa DIY was too small for the W18E001. The size must be 1xSD on the small closed end and 4xSD on the big open end. Getting the W18E001 into the right size cabinet requires about 62 liters. Plus, the cabinet must be strong enough to support the low bass without flexing. If the cabinet flexes, the bass will go right through the cabinet walls. This makes for a big heavy cabinet and 62 liters internally. Heck, at 70 liters I could use a L26 or W26 woofer and get real bass.
I understand your fixation with size. Size does matter. Going just a little bigger will net much more performance from a real woofer.
Dave
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Dave,
What's your finalized port length?
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Dave,
What insulation did you use on these? That does not look like Walmart's bed cushion foam.
Al
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In addition to the 1 1/5" baffle, would the midrange have improved with spikes on the bottom?
Al
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Fair Questions guys. Thanks for asking them.
I continue to use the sandard length port . It's 1 7/8" diameter and 5 1/8" long.
The foam used is from Madisound. I think it's 7/8" thick. It was slightly thinner, and less obtrusive behind the driver. I thought it might work better but never a/b tested this against anything else. Past experience and testing revealed no difference between WalMart mattress cushion and flat acoustic foam.
I believe the thicker baffle would help the midrange of the 1801BF, but again... this difference is very small or not audible. I thought (?) that I heard something in my living room. However, it wasn't present at Dennis Murphy's home. Dennis couldn't hear it. I couldn't hear it. Gary couldn't hear it. Nonetheless, it might be present in some circumstances. As such, I recommend a thicker baffle for those who build the 1801BF.
I really can't comment on the spike issue. I didn't experiment with this and therefore have no first hand experience with this application. My comments would be theoretical and metaphysical only. Such disssertation is most often very long and convey's very little.
Dave
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Fair Questions guys. Thanks for asking them.
I continue to use the sandard length port . It's 1 7/8" diameter and 5 1/8" long.
The foam used is from Madisound. I think it's 7/8" thick. It was slightly thinner, and less obtrusive behind the driver than mattress pad foam. I thought it might work better but never a/b tested this against anything else. Past experience and testing revealed no audible difference between WalMart mattress cushion and flat acoustic foam.
I believe the thicker baffle would help the midrange of the 1801BF, but again... this difference is very small or not audible. I thought (?) that I heard something in my living room. However, it wasn't present at Dennis Murphy's home. Dennis couldn't hear it. I couldn't hear it. Gary couldn't hear it. Nonetheless, it might be present in some circumstances. As such, I recommend a thicker baffle for those who build the 1801BF.
I really can't comment on the spike issue. I didn't experiment with this and therefore have no first hand experience with this application. My comments would be theoretical and metaphysical only. Such disssertation is most often very long and convey's very little.
Dave
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This question was posted elsewhere and bears good validity herein:
What dimensions are 'finalized' for the 1801F version? I heard the volume isnt much larger than the 1801B, but it is probably 2x the height....so....less depth?
The external dimensions of the 1801F are again:
All exterior panels are built from 3/4" MDF and there is 1 vertical brace connecting the sides/top/bottom. The external dimensions are 40" tall x 7 1/2" wide x 10" deep. The tweeter is offset 1/2" and the flange is about 3/8" down from the top of the cabinet.
This assumes 3/4" material on the front & back of the speaker. I continue to think 3/4" thick MDF is fine for the back panel, but certainly the front panel could be 1 1/2" thick. This effectively makes the 1801F cabinet 10 3/4" deep.
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OK, After having done one 1801b, I'm going now after a couple of 1801F's ...
While instructions are clear, I will like to see photos of any 1801F being assembled. So any picture of the process will be appreciated.
Salva
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I didn't take any frame/assembly pictures.
Dave
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Salva,
Why not wait until Dave releases the 1801b 3-way with the 10" driver?
I would like to build the SCC300 3-way since I have most of the drivers except for a pair of W18EX001.
Other alternatives, check the cabinet designs from Northcreekmusic.com. You can find excellent tips on cabinet designs by reading their cabinet instructions.
You can also post in the Madisound forum and ask for input on building a "Bob QWMLTL" like B. King made recently using Revelator 7" and Seas Millenium tweeter. It should work nicely with the 1801 drivers.
Al
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Well.. this is why ...
I Did a couple of 1801b's for a friend, I wanted to see if I was able to do them, and if I liked them
Indeed l liked them, a lot.
Reason that I did them is because I intended them to be them the first step into my ultimate goal, design a 2 way thin floorstanding speaker that matched my furniture ...
Then I learned abt the 1801F. and that is what I'm now after...
I dont have space for other than the thin 1801F .... Perhaps a separate subwoofer, but not in the 1801F ...
By the way, I've posted the photos that Michel sent me of the manufacturing of 1801F's for all to see in my place ...
http://www.videoacustic.com/sferrairo/1801F/
Salva
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Error, pls delete
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I am not sure what you want deleted, but I cannot do this. Actually, I can't delete my posts. The only related possiblity is to edit the most recent post.
Also, the intenal 1801F pictures look good and right. Would you mind if I put them directly in this forum string? Other's may appreciate these pictures too.
Dave
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Yes, Indeed they are Michel's photos, I guess that will it be OK from him.
I meant that I doble post by mistake, that's why I asked the post itself that says "pls delete".
Salva
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Yup, feel free to post them in the string, Dave. I have no clue on how to do this. If anyone wants a few more, I've got some.
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These pictures are useful pics of the 1801F. I thought increased visibility here might be helpful.
Thanks for taking them.
(http://www.ellisaudio.com/1801Fframe.jpg)
(http://www.ellisaudio.com/1801Fup.jpg)
These are darn near identical to how I built my 1801F speakers. Probably the only change that could be implemented is a thicker back & front panel. I didn't do this, but the panel exhibits some knuckle resonance. Thicker panels would be more solid.
To post an image in this forum simply insert the image URL beteen two "Img" buttons when submitting a post.
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Hi Dave, couple of Q abt the 1801F's ...
Bass Reflex port:
You made no mention of it's location, I guess that will be fitted on the back of the cabinet centered and low (near the floor).
- Is that correct ?
I gues that position will be not very critical.
Stuffing:
Now, I was "paranoid" abt stuffing the 1801b's and now is the same with the F's ... Being this speaker so tall, and having no access at half of the cabinet when is closed.
- How do you stuff the cabinet ?
Im doubting on stuffing the walls before closing the speaker, or just put stuffing inside, doing the latter will have the danger of blocking the BR port.
Midwoffer:
There is no mention on position of it, I guess that just centering ion the speaker and lower it say one centimeter from the edge of the tweeter will be enough.
- Am I correct ?
Salva
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You made no mention of it's location, I guess that will be fitted on the back of the cabinet centered and low (near the floor).
- Is that correct ?
Yep, that's correct. I put my near the floor.
I gues that position will be not very critical.
Yep, correct again :)
Now, I was "paranoid" abt stuffing the 1801b's and now is the same with the F's ... Being this speaker so tall, and having no access at half of the cabinet when is closed.
- How do you stuff the cabinet ?
I simply stuff the regon around the woofer hole with foam. This is essentially the top, oh, 15" of the cabinet.
Im doubting on stuffing the walls before closing the speaker, or just put stuffing inside, doing the latter will have the danger of blocking the BR port.
Not much stuffing is needed to kill the midrange echo. One VERY experienced guy simply uses a 5" diameter (approximately) wad of acoustastuff centered in the cabinet behind the midwoofer of his slim tower speakers. This works great for him, but is certainly impractical for shipping speakers. That acoustastuff would obviously move.
Midwoffer:
There is no mention on position of it, I guess that just centering ion the speaker and lower it say one centimeter from the edge of the tweeter will be enough.
Yep, you are correct again :)
These are excellent questions. You generally assumptions are very accurate!!! Thanks for seeking confirmation herein :D
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I guess that being an engineer I needed precise drawings, I become nervous in any project without precise specifications, so that being the case with the 1801F I draw a crude drawing to help me, just in case if is of use to anyone here it is:
http://www.videoacustic.com/sferrairo/1801F/1801F.pdf
(sorry, measurements in centimeters, Europe here)
Salva
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It takes me sooooo much time to do this kind of stuff. I know it's easy, but I am a rookie with computer drawing and it takes me a long time to accomplish this kind of work.
The drawing was so good that I kinda... well... stole it. I converted it to a picture so it can be viewed openly here. Some picture detail is lost, but this will make the drawing much more visible here. I'd hate to see someone miss the drawing. :)
(http://www.ellisaudio.com/1801Fdraw.jpg.gif)
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Hi, I'm in the middle of the completion of two pairs of 1801F's, cherry veneered. You can see the photos here:
http://www.videoacustic.com/sferrairo/1801F/1801f2/
While glueing the veneer has been easier than I thougth, the difficult part has been the trimming of the venner, it has been impossible to avoid some "chipping" while trimming. I have used raw venner, the only thing available locally, indeed all the ppl that I've mentioned double ply or paper backed venner, where unaware of them.
- Any tip to avoid chipping of the veneer while trimming with a router ?
- Could anyone make a close up photo of double play and paper back veneer so that I can shoy to my local supplier ?
Tks
Salva
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My camera isn't viable for pictures, but the site for obtaining 2-ply veneer is this one:
http://www.tapeease.com/Home.htm
They have many pictures on their site. Also, Veneer isn't very heavy. You might consider ordering from Tape-ease directly. I think they charged me $17 for delivering 1 sheet. Veneer is pretty light and his packing methods are very solid. He might ship overseas. You will have to ask Dave at Tape-Ease about this. I have ordered... oh... $2000 in veneer from him. He is good business.
There are flush trim bits that cut up or down, but IME, a very sharp router bit is more important. My veneer is fairly solid, but find much less chipping/splinter with a very sharp bit. I have tried many different brands of router bits and find the bits from www.ridgecarbidetool.com superior. The Amana carbide is a very close 2nd. The rest of the carbide cutters sold at retail stores are mostly sub-par. The bits from ridgecarbide a very good. I have a single flush trim bit that is ONLY used for trimming veneer. This bit obviously remains very sharp.
Hopefully these remarks are somewhat helpful.
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I perused your pictures and have a couple thoughts.
You might consider using a foam roller to spread the contact adhesive. Use two coats. If you contact adhesive is extremely thick, you can thin the adhesive with lacquer thinner. This helps me spread the contact adhesive very evenly and reduce veneer ripple.
Are you able to obtain 3M products? If so, you might consider the 3M water based contact adhesive. The stuff works great. The stink is mild but the "stick" is amazing. This stuff is really the best of both worlds. Then.... if you are using raw veneer this might be a bad idea. Some penetrating wood finish might cause the adhesive to come unglued.
You also might consider using a hard rubber roller to press the veneer. I puchased one for about $13. I think wallpaper guys use these things too.
And... your shirt is waaaaay to clean! You really need to get more sawdust on that shirt! My wife really apprecaites this. She loves it when I "share" my sawdust with her and the kids.
Seriously, having a clean environment when veneering is very important. Any spec of sawdust will telegraph through the veneer. Good work!
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A low-tech approach to avoid veneer chipping might be to run some tape along the cut line. The tape would "support" the tender veneer while the cut is made.
JD
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I totally forgot about this. Using tape on the veneer will help!
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OK, I tried the paper tape thing and really helps. The other tip I've to consider is the "applying" glue method, my method is time consuming and involves "huge" cuantity of glue. I will use 2.5 liters in two speakers wich is way to much.
Anyway this has been my first approach to venner and the second to speaker building, this is a learning process it is not hard once you know but getting there takes time.
Just for the record I estimate that to do a full set of 1801f's from zero to finish will take me 30 hours, so don't take this as a "weekend" proyect but as a "summer holiday" one.
Seeing the amount of time it takes me I'm amazed of the low prices cabinet makers charge.
Bye from now.
Salva
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This timeline sounds about right. When building 1801 cabinets in groups of @ 5-8 pair it still takes me about 20 hours to finish a pair of 1801s. Building a single pair of 1801Fs should consume about 30 hours.
I really thought that I'd get much faster at cabinet builing after streamlining my methods. My methods are quite effecient, but still consume considerable time.
I have learned that MANY cabinets are made in SE Asia. Those guys obviously work VERY cheap.
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Hi again, I've reduced the size of the photos so that will be easy for low slow connections ppl to see.
I've added a few ones so that you can see more on the process of building them.
http://www.videoacustic.com/sferrairo/1801F/1801f2/
And by the way, that's me :mrgreen: working with the 1801f's
(http://www.videoacustic.com/sferrairo/1801F/1801f2/DSCN1739.JPG)
Salva
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OK, I posted a retaled issue on a separated thread, but I will keep it to the 1801F since it is 1801F related.
I've been doing experimentation with different finish, I wanted to keep the natural "caracter" of the wood. The one that I liked the most was red cherry tinted wax, applied by hand.
http://www.lakeone.net/
Attached are a 1801F with sealer only (rigth) and one with three wax coats.
(http://www.videoacustic.com/sferrairo/1801F/1801f2/DSCN1760.JPG)
Hope you like them.
Salva
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In the past I used Wax too. I actually tried several different kinds of wood finish wax. I found the floor-wax with silicon the best, but this is certainly only my opinion. Wax will produce a very nice even sheen in VERY little time. Wax requires some re-application a couple times per year, but this isn't terribly tedious. Possibly for this reason wax received a "bad" reputation as a furniture finish, but I kinda like the stuff.
I think the only real downside to wax is that it's a very poor vapor barrier. Wax will allow humidity to solid lumber. The obvious impact is expansion in high humidity, and contraction in low humidity. The importance of the is not critical depending on climate and completely nullified when using veneer on MDF.
Wax can be a very smart finish choice.
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Finished, pleased with the result. A couple of photos just for fun.
(http://www.videoacustic.com/sferrairo/1801F/1801f2/DSCN1762.JPG)
(http://www.videoacustic.com/sferrairo/1801F/1801f2/DSCN1763.JPG)
Salva
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Salva, the finished results look very clean.
I do notice one of the speakers doens't align perfectly with the cabinet. I suppose the floor could be slightly uneven, but the bottom of the speaker could also be uneven. If the latter is true, I suggest using some rubber/felt pads on the bottom of your speakers. Place one of these pads in all 4 corners, then file/sand these pads until the speaker stands correctly.
Dave
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Yes, the base is sligthly uneven but I did not bother me, I've ordered spikes to both raise the speakers from the floor and level them.
I had plans since the beggining to use spikes.
The only thing that I've noticed is that the bass is less "bommy" than the 1801b, I have not played with the BR thougth.
I will measure response on the next few days, I'll post the results.
Salva
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I've done a small php script to make a thumbnail show so that it will be easyer for anyone to see the process of the 1801f construction.
http://www.videoacustic.com/sferrairo/1801F/1801f2/thumbs.php?1801F/1801f2,100,73,8
Salva
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OK, been using the 1801F's for aa few days now .. sound is very lean that is true for the bass as well. The 1801b's that I did had a more "boomy" sound the F's are more natural with a greater bass extension but the b's have a more "expetacular" sound with certain music.
In both cases BR length is kept to the full length Dave supply.
I will like to get from the F's some of the bass that I got from the b's ...
- What BR port length is ppl using on the F's ?
- Do you think that reducing the port I will get a more "boomy" sound ?
Salva
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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.
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A couple of photos more, all the fittings placed, and grille added. Hope you like them.
Salva
(http://www.videoacustic.com/sferrairo/1801F/1801f2/dscn1805.jpg)
(http://www.videoacustic.com/sferrairo/1801F/1801f2/dscn1806.jpg)
(http://www.videoacustic.com/sferrairo/1801F/1801f2/dscn1808.jpg)
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great pics.
How did you construct and attach the grills?
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This is a very decent picture of John's speakers:
(http://www.ellisaudio.com/Johns1801.jpg)
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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
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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.
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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
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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.
(http://brainwatch.us/images/ellis1801bf.JPG)
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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!
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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.
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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
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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 :D
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
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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.
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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
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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.
(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.
(2) Is that port tube hole diameter correct?
Yep, 2 1/8" is what I use.
(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.
(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]
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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.
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I posted your response in the appropriate string here:
http://www.audiocircle.com/index.php?topic=7739&postdays=0&postorder=asc&start=40
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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
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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
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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
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Salva,
I just happened upon these latest posts about port length.
I went thru this same exercise a couple years ago.
NO port, just a hole, gave a very noticeable boominess to the bass. If you like this now, I think you will soon grow tired of it.
I then tried a 2" port, got more bass and no boom.
I settled on a 3" port. It sounded same as the 2" version, but was easily made by cutting the original 6" port tube in half.
I believe with the shorter port tube the rolloff characteristics get ruined, but since it's a 24db. rolloff, it's not really noticeable, certainly not to me.
Dave's 1/2" shortening method is really the proper way to do it, but I doubt you'll hear much difference with each 1/2" increment. The difference is likely measurable however, if you have a way of measuring it. And you'll likely get very tired of taking the woofer in and out in order to replace the port tube.
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Hi there, I'm finishing my second 1801F. I have posted some photos of it on a spanish DIY forum. I guess that they will help other people doing them. Mainly with the veneering thing.
http://www.matrixhifi.com/foro/viewtopic.php?t=713
Salva
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Hi there, I'm finishing my second 1801F. I have posted some photos of it on a spanish DIY forum. I guess that they will help other people doing them. Mainly with the veneering thing.
http://www.matrixhifi.com/foro/viewtopic.php?t=713
Salva
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Thanks Salva, very good pictures! I really like the lab coat too. It's pretty professional looking!
Dave's 1/2" shortening method is really the proper way to do it, but I doubt you'll hear much difference with each 1/2"
There really isn't much difference with 1/2" increments. This is the minimum amount that I hear audible impact.
And you'll likely get very tired of taking the woofer in and out in order to replace the port tube.
About 6 months after your 1801 kit order I purchased externally mounted port tubes. These are now shipped with all 1801 kits. The port process is MUCH easier and much quicker. It simply slides a 2 1/8" hole from the outside of the cabinet and fits with friction. The seal is actually very tight, but some folks may want a 100% air tight seal via a gasket. Forming a gasket can be done with poster putty (temporary) or silicone (permanent).
Thanks a bunch for your continued contributions here gents :!:
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I was telling Dave what I would do differently if I were to make another pair and my thoughts seem to fit in this thread, so here goes...
I would like to make a floorstanding speaker that was chambered just like the normal 1801. This would allow me to do several things such as put the xover in the bottom chamber portion of the cabinet, NOT build stands, put shot/ sand in the bottom cabinet, bi-wire in whatever fashion I wanted (side by side or over and under) and not have to worry about hookup because I would have a false bottom (or not bottom in the post area at all) allowing me to get in to the posts :) I'm just not sure about the baffle issues and the crossover though...
Thoughts?
Thanks,
Jim
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I'm just not sure about the baffle issues and the crossover though...
Based on my experiments, I believe anything between a baffle width of 7 1/2" and 9" will be fine. No crossover changes will be necessary.
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Hi, Just finished my second pair of 1801F's .. (Hei, I just build three 1801's!!) Now, this time I have taken the oportunity to put a great deal of stuffing and to shorten the lengh of the standard port by an inch.
I can say that I like the bass of the 1801b more. I have constructed a adjustable BR port with a couple of PVC pipes and I am going to make a AB coparation in my home 1801b vs 1801F. Trying to match the bass caracter of the 1801b with the adjustable ports.
I'm thinking that perhaps having such a large side pannel can have a effect on rigitity hence the bass suffers. On the 1801b the area with no brace is smaller with will banefit the bass.
mids and higs are the same to my ears.
I'll post my AB results on monday and a photo tonigth.
By the way, I have discovered a coupe of tips for veneering and finishing:
Vennereing: White carpenters glue, dryed with a hot iron with a sheet of paper in the middle leaves a smooth no bubbles venner in no time at all.
Finishing: Use hand rubbing stuff, that gives excelent results with almost no effort. Using a brush and trying to get a smooth finishing surface or uniform tint is almost impossible.
Salva
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(http://www.videoacustic.com/sferrairo/1801F_2/lowres/DSCN2109.JPG)
(http://www.videoacustic.com/sferrairo/1801F_2/lowres/DSCN2108.JPG)
Salva[/url]
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I finished building my 1801F's (except for the grilles) about a week ago. If anyone is interested, I am also constructing a web site about the project. It's not complete, but it's getting there.
http://home.hiwaay.net/~rgs/ellis1801f/default.html
I just read Salva's post about his latest set of 1801F's. I also used the dry-bond, iron-on veneer method. I can't compare it to using contact cement, but I'm happy with the results I got (at least so far). I also used wipe-on stain and poly.
Salva, when you say you prefer the bass of the stand-mounted 1801, which type of bass are you referring to--upper bass, mid-bass, low-bass? Or is there some particular aspect of bass performance (slam, etc.) that you've noticed?
I will say that it was a blast building these speakers and firing them up for the first time. I'd definitely encourage any prospective kit builders to go ahead and take the plunge.
Ron
(http://home.hiwaay.net/~rgs/ellis1801f/finalRight.jpg)
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Salva,
I just happened upon these latest posts about port length.
I went thru this same exercise a couple years ago.
NO port, just a hole, gave a very noticeable boominess to the bass. If you like this now, I think you will soon grow tired of it.
I then tried a 2" port, got more bass and no boom.
I settled on a 3" port. It sounded same as the 2" version
Yes, I started with 3", that was was not enough then I tried 2" that seems OK, sometimes seems to much (boomy) but at mediums and low volumes the soud has a lot of "body".
I guess that a little more than 2" will be the correct size. That is the case in my room. Beware room dinamics change how the speaker behaves bass wise.
A question to dave, Do you think that 2" can have other effects than increasin the frecuency tuning of the BR ?
Salva
PD. By the way, the 1801 still put a smile in my face each time I hear a good recording in them.
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A question to dave, Do you think that 2" can have other effects than increasin the frecuency tuning of the BR ?
I am not sure what "BR" is, but this probably isn't critical.
Making the port shorter will raise the tuning frequency where the bass from the port will reinforce the bass from the front side of the cone. There really aren't any dangers.
I have thought about this phenomena of port energy change, and think that I hear something in this regard. The bass seems to be more prominent at higher spl. I think (??) this may be due to the lack of port flare. This lack of port flare creates an inconsistent airflow through the port that is dependent upon port velocity. As airflow volume through the port increases, the turbulence should also increase. This would raise the tuning frequency. I am not certain this is true, but it seems fairly reasonable.
I really wish that I could a/b test this phenomena, but I can't. I don't have any more of the straight sided ports. The new port for the 1801 is an internally and externally flared unit. It sure looks nice, and it might actually improve performance.
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I am not sure what "BR" is, but this probably isn't critical.
Ah! sorry, I meant Bass Reflex. OK, the only thing was that on my room/speaker positioning 6 cm seems to be the best bass compromise. My worry was if by cutting the port on more than half can have any other effect on the speaker than raising the tuning frecuency of the Basss Reflex.
One thing that I have tougth is the claim of B+W that the usage of "portflow" tecnology (that is, making small holes like in a golf ball) and having a flared port wil have any effects on bass.
Rigth, any way. I am more than happy with the bass of my 1801F. No sub needed for music.
Salva
Flowport link
http://www.bwspeakers.com/index.cfm/fuseaction/products.techfeatures/ObjectID/3A7554F4%2D4779%2D11D4%2DA67F00D0B7473B37
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One thing that I have tougth is the claim of B+W that the usage of "portflow" tecnology (that is, making small holes like in a golf ball) and having a flared port wil have any effects on bass.
Well, if the port encountered omnidirectional air flow like a golf ball, the dimples make extremely good sense. A very good M.E. (Mechanical Engineer) explained to me that a dimpled golf ball will fly about 30% further than a smooth golf ball from the tee-box. The M.E. explained that the dimples in the golf ball essentially grab the air flowing around the golf ball and hold it securely. The result is the turbulent trail behind the dimpled golf ball is much smaller than the turbulent trail behind a smooth golf ball. The dimples really improve the drag/turbulence of the golf ball. However, the reason dimples are used is because the direction of airflow over the golf ball is uncertain. If the direction of airflow is known, ridges or fins will perform much better than dimples.
There is some dicsussion on this matter here:
http://www.eng-tips.com/viewthread.cfm?qid=107764&page=1
However, this discussion appears incomplete. These gents discuss airplanes, but not cars. The example the M.E. used to describe the ideal trubulent reduction applied the model of the Mustang SVO. The double fins on the back were postioned to accomodate airflow at a specific velocity.
(http://www.mustangsvo.org/photoalbum/circleoforangeshow1999/19990711_04_DaveS_7x5.jpg)
As the airflow over the SVO would become turbulent at the back end, the first fin would catch the air, and maintain the non turbulent flow. Yes, the fin actually reduces turbulence. This seemed strange, but the M.E. explained the dynamics and it made very good sense. Then, as the airflow was again about to become turbulent, the second fin would catch the air and reduce turbulence. These fins on the back of the SVO were engineered for a specific velocity in a linear direction through the air. There are similar fins on the back of many race cars, but they perform other duties (i.e. downforce), and I cannot address this.
Nonetheless, my point is; When the direction of airflow is known, ridges/fins will outperform dimples. The design/spacing of these ridges will be most effective when applied to the velocity and direction of airflow. The velocity will obviously change, but the direction (fore and aft) will remain the same. If a guy wanted to engineer an ideal flare for a port tube, ridges/fins should be used. IMO, the only reason to use dimples is marketing. Aparantly the B&W marketing department believes their customers are more familiar with Golf than NASCAR. I think they are right.
Please understand that I am not an M.E. or Aero Engineer. However, there are several of these guys in my office that golf. There is another who is a NASCAR fan. The subject of dimples versus fins is quite simple for these guys.
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Yesterday was a good day for me and my 1801Fs.
First of all, I officially finished my speakers by finishing the grilles.
(http://home.hiwaay.net/~rgs/ellis1801f/grilles.html) The speakers are more domestically friendly now.
Better yet, I started getting much better sound from my 1801F's. Anyone who has read some of my recent posts knows that I've been bothered by my 1801F's sounding a bit forward. I had mistakenly attributed that sound to a tweeter level that was too high.
That wasn't the problem. The problem was the converse. The low frequencies were a little too low (in level). As a quick test, I just removed the ports altogether. I should have done that before, but the ports fit so tightly getting them out was a real bear. On one speaker, I had to remove my access panel, reach inside, and twist the port out. If I hadn't built those access panels, I'd still be wrestling with, and cursing at, one of the ports.
Now the speaker sounds much more balanced. Male singers now have chests. There's a better foundation for the music in general, and I'm starting to better understand what all the fuss about the 1801's is about. Before, most of my CDs sounded a bit "whitish" or "bleached." That's no longer the case.
I think I'm following Salva's footsteps. I know he started out with lean sound, then removed his ports (resulting in too much boom), then found an optimal port length. I still need to do that last step. But playing with the port lengths is going to be much easier than mucking around with resistors, which was the path I was about to take.
Anyway, I think I'm now well along the road of being another satisfied 1801 owner.
Ron
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Ron-
Very nice grilles...I have been trying to decide the best way to add grilles. I like your approach the best with magnets.
I have a few questions if you dont mind:
The grille frame, is it plywood or mdf? and how did u get the large angle on the inside? (e.g. profile...router?)...looks like a very large profile bit if it was a router.
Where did u find the best magnets? I havent really looked but thought I would ask to reduce my search.
Again, very nice looking speakers!
Thanks-
Jim
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Hi Jim,
Thanks for the kind words.
The grille frame, is it plywood or mdf? and how did u get the large angle on the inside? (e.g. profile...router?)...looks like a very large profile bit if it was a router.
The frame is 1/2" MDF. I used a 1/2" chamfer bit on the inside edge, and a 3/8" roundover bit on the outside.
Where did u find the best magnets? I havent really looked but thought I would ask to reduce my search.
I bought mine from Parts Express. I'm pretty sure this link will take you to the magnets I bought.
http://www.partsexpress.com/pe/showdetl.cfm?&DID=7&Partnumber=329-042
I didn't shop around much for mine, because I was also placing an order for the spikes and grille fabric at the same time. My Rockler catalog includes magnets that look similar.
These magnets are really strong. Before I bought them, I worried if those small magnets would be strong enough to hold the grilles. After I got them, I worried if they were too strong. Both worries were unfounded.
At some point, I'll add a grille drawing to my web site.
Ron
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Very nice work Ron, especially for documenting your experience in your website.
Did you use anything to have a tight-seal for the access panel?
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Very nice work Ron, especially for documenting your experience in your website.
Did you use anything to have a tight-seal for the access panel?
Thanks, Al. I hope to finish my web site in a few weeks (but I've been hoping that for many weeks.)
I didn't seal the access panels. They fit very tightly, and I don't think they are leaking air. I did start to use weather stripping to seal them, but that made the panels stick out, so I removed it. (By that time, I was anxious to be done, and to start listening.) If I ever really start to wonder, I can run a rabbetting bit around the perimiter of the panels, then use the seal.
I tell you, I cursed those panels when I was building the cabinets. It took me two tries to make panels that fit properly. But I was glad I did it when I mounted the crossovers (and when I was fighting with that sticky port.)
Ron
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I can understand the frustration. It's very tempting to make an external crossover.
Al
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Dear Dave,
for my curiosity, why did you choose to design a B-version? Do you
think that bookshelfs are as good/better than column versions (with same drivers and equivalent volume)?
kind regards,
Pierre-Etienne
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for my curiosity, why did you choose to design a B-version?
Both the 1801F and stand mounted 1801 are the "B" version with the same crossover. The explanation for the B version is here:
http://www.ellisaudio.com/1801bchanges.htm
Do you think that bookshelfs are as good/better than column versions (with same drivers and equivalent volume)?
All of these comments are mentioned previously. My summary is... the quality of sound is the same.
Dave