a final post and FYI for all the bottom-feeding modkateers out there. these speakers are on final in-store closeout for $14.97 per pair. |
i have since placed 2 ohm resistors on the positive tweeter terminals to very good effect.
chip, i also noticed the vibration at the rear of the cabinet, and took the following measures: aside from putting generic dynamat on the inside of the cabinet, i got some 2.5" by 0.5" oak from lowes and gorilla glued it to the back of the cabinet on either side (9 10/16" long). this just clears the port area, but not the terminal cup. so i removed the terminal cup (a major PITA, btw), and glued another smaller piece of oak with rat shack binding posts. just file an oval area from the oak on the sides and you could easily keep the spring-loaded terminal cup.
thinking of also gluing some oak to the bottom of the cabinet which would further add some stability/mass without affecting aesthetics. hey, it's cheap and easy.
regarding the braces: THEY DO FIT, but in the following way: i requested and placed TWO per speaker, on either side in between the drivers. all you do is discard the square wood piece that is supposed to go with the non-threaded end and snug up the round brace to the baffle in that area. i didn't put any dynamat on the inner back in the area where the square piece for the threaded end fits, and gorilla glued front and back. it was a bit of a hassle reaching in to turn the brace while keeping it straight, but hey, i'm satisfied.
even with all this, mine seem to sound a bit better/clearer stuffed.
hard to tell if the port was a random act or a design intention. it's too thick to be a discarded chinese toilet paper roll :-) :-)
hope this helps a bit.
happy holidays! |
Hi again -
Sorry for the long delay, I've been very busy and somehow missed your last post. I've been running the stock and litekeys speakers in mono in my bedroom (not continuously) since my last post to really break them in. The litekeys has definitely improved - the bass level has come up a bit and the tweeter is a little more friendly. But for my ears, I still think adding some resistance on the tweeter will balance it out nicely.
I haven't the burning need to stuff the port on the litekeys version as I did with the stock. The addition of the crossover has cleaned up the woofer sloppiness quite a bit, but it's too hard to tell until I have two matching speakers running in stereo. I kind of wonder whether any analysis went into the design of the port at all - or did they just stick a random tube in the cabinet?
The rear of the cabinet has quite a bit of vibration which must be adding coloration, (as does the plastic grill frame, which is easier to eliminate) Even though there is a clever adjustable brace included in the kit, it can't really be engaged in a useful location inside the cabinet because the woofer takes up almost all of the front baffle. So adding stuffing may be useful to help damp some of that.
I'm hoping to finish up playing with these over the Xmas holidays, and I'll post my final results then.
Cheers, Chip |
just now catching up with the thread. opalchip, your comments are very intersting and much appreciated.
i contacted litekeys and he said he intentionally left the tweeter a little "hot," and simply placing a 2 ohm resistor in series with the positive terminal should do the trick (he actually said 2-4 ohms depending on taste so opalchip certainly had the right idea). i couldn't imagine that litekeys didn't take the 6 ohm impedance of the new tweeter into consideration.
opalchip, regarding the midrange, are you stuffing the cabinets or ports? i'm referencing your comments from 1/22/06. i plan on addressing the treble issue first, then listening more intently for your perceptions of the mids. i'm wondering if a little experimentation with the type and amount of stuffing material may be a potential solution. |
This morning I A/B'ed the single Litekeys Presidian against a Dick Sequerra Metronome, which is admittedly a dated design - but cost about $800 for the pair new, and the Presidian was hands down the winner - with the one drawback being that softness in the lower mids. (Can't compare imaging obviously as I only have one Litekeys speaker right now.)
Also - Since I've hardly used the Presidians at all, even before the mod, and the Litekeys side has a brand new tweeter, I'm going to let them break in for a few days before trying my further ideas. |
Well - I completed the upgrade on one of the Presidian speakers tonight and A/B tested against the still stock one. I used an old Marantz receiver for 2 reasons - it has the ability to run R & L speakers from one mono source AND it has excellent tone controls (Bass/Mid/High).
I need to do some more experimenting but here's what I've observed so far:
1. The upgrade kit is VERY reasonable for the amount of time Litekeys must put into it AND it is definitely an improvement over the stock. It took about 2 hours start to finish ( I soldered all new joints). You have to have fairly nimble hands to install the crossovers inside the cabinets.
2. Most of the improvement comes from the upper mids to the highs and it is not subtle - if you had to pick either the Litekeys version or the Stock version of the Presidian and not mod further, it's not a contest. The Litekeys is a big improvement.
3. That being said - the situation is more complex. By playing around with the tone controls on the receiver I was able to improve either Presidian considerably. On the first A/B comparison it became obvious that the stock Presidian is rather attenuated in the highs. The sound is muffled compared to the Litekeys speaker. However the Litekeys version is a bit lacking in the low end by comparison - which may simply mean, in a 2 way system, that the tweeter is a little too hot.
4. The original Rat Shack tweeter states 8 ohms on the back, while the upgrade (a Dayton ND20TA, cheap yet well-respected among DIY'ers for it's flat response) is nominally 6 ohms. However actual measurements from Dayton show it really runs about 5.5 through the meat of it's freq. range.
These relatively different tweeter efficiencies may explain a lot of the immediately noticeable audible difference between the stock and the litekeys Presidians.
I found that if I turned the Treble control nearly all the way up that the stock speaker improved considerably - possibly even bettering the Litekeys in the extreme highs and while maintaining the better bass at the same time. But it's hard to A/B that reliably because it involves flipping 3 nobs as simultaneously as possible. On the other hand, with the Litekeys speaker, turning the bass up a lot and boosting the mids a little yielded a substantial improvement to my ears.
5. So I don't feel that the Presidians are yet optimized. In order to sort this all out I feel I need to try a few things - in this order:
A. What if I just replace the stock tweeter with the Dayton in the 2nd (still stock) speaker and leave it untouched otherwise?
B. What if I add the Litekeys crossovers but keep the original tweeter?
C. What if I add, say, a 3 ohm resistor (probably about right) in line with the Dayton tweeter in the Litekeys version speaker to better balance the tweeter and woofer responses?
D. What if I add a 3 ohm resistor in line with the woofer in the stock speaker to attempt to better match the tweeter level?
I'll tell you what sounded better than either one at this point - stacking them on their sides and running both of them simultaneously with the balance a little higher on the Litekeys speaker. Their different tonalities balanced out very well and it really sounded pretty impressive. You could make a case for buying two pairs and running a baby "line array" like this - with one pair upgraded and the other stock. Not bad for about $125 total!
I'll report back here when I've tried as many of these as I can before my kills me.... |
sfar, as i stated above it was my own experience with the m-7 upgrade that led me to approach larry about the presidian. this speaker "bottom-feeder" upgrading/modding is just plain fun, especially while finances are temporarily lean.
QUESTION: could someone provide me a measurement (in millimeters) from the center of the stock presidian tweeter to the center of one of the fixing screws? i have already snipped off the phase plug thing to fit the new tweeters. thanks in advance. |
fwiw i wasn't informed of the subsequent price, but i do consider it to be more realistic.
nothing is going to transform these speakers into "world beaters," but they do become more neutral, detailed, and lively in the treble (without becoming harsh). they haven't seen the inside of the closet since being modded.
the cabinets do also need to be stuffed imho. |
I got the upgrade kit for the Minimus 7 and installed it a couple of days ago. The improvement in the sound is dramatic, well worth the $20 cost of the kit and the half hour it takes to install the new crossover.
I've always liked the Minimus 7 because of it's very small size and construction. Litekey's kit turns it into a very respectable little speaker.
Be prepared for some head scratching over the included instructions but once you sort it out it's pretty straightforward. |
I'll post a follow up as soon as I finish them - my plan is to upgrade just one speaker first so that i can compare side by side.
I don't expect them to become world beaters, and it practically doubles the cost of the speakers which I was about to give to a friend in need, but I can't resist the fun of trying the mods.
If they can be used with our bedroom TV (where the baby has full access to pound and chew them) for a slightly better hearing of Live At Lincoln Center, Austin City Limits, etc., we'll be happy. |
Opalchip, please let us know what kind of difference the upgrade makes. I was on the verge of buying the kit myself but in a rare moment of self-restraint I backed off, remembering how many pair of speakers I already have littering my basement. I did order one of the kits for the Minimus 7, though.
|
Thanks for the heads up - just bought them. I'd assume he'll post another set soon.
Now wondering if I should have waited for a litekeys upgrade2.0 - which would undoubtedly convert these into a line-array 3-way design with the addition of two more pairs of Presidians! :) |
I see that litekeys has posted his upgrade kit to the Presidians on ebay for $27.50. He says he may not make many of them because of the expense and labor involved so if you're interested you might want to jump on them, do a search on his user name, 'litekeys' or on 'Presidian.'
|
Musicdoc,
For more information about Open Baffle Speakers than you would ever care to read, go to the Open Baffle Forum at audiocircle. Also look at the "Gravity Well of a Darkstar" Thread in the Red Wine Audio forum at Audiocircle. It's now 1200 post and 81,000 views strong! Here are the links:
Open Baffle Forum
http://www.audiocircle.com/circles/index.php?board=90.0
RedWine Audio Forum
http://www.audiocircle.com/circles/index.php?board=78.0
Enjoy the reading!
TIC |
i'm also interested in the specifics of this inexpensive OB project (e.g., exactly where in the baffle is the driver mounted etc.). one wonders how to make such a thing more aesthetically acceptable--maybe triangular MDF braces along the sides for support/stability and the proper angle, sanded and painted an unobtrusive chick-friendly pastel, along with some type of removable (? magnetic) grill? certainly a challenge. |
Johnk,
You're talking about a simple open baffle speaker, right? For those who didn't follow John's previous post, it is simply a piece of plywood with a hole cut in it and a driver mounted in the hole. A shelf bracket is mounted along the bottom of the piece of plywood sticking out to make a simple prop to keep the plywood from falling over.
It can be a great sounding speaker, but it will not pass the WAF test. This is a "man cave speaker" only IMHO.
John, what kind of bass response are you getting with the Fostex? There are some "OB specific" drivers coming out soon, including one from Hemp Acoustics. If it is as good as the current FR8.0DIY (installed in a simple bass reflex box) it will be outstanding.
Enjoy,
TIC |
JohnK, Thanks for your thoughts. I am looking to make a small bookshlf with a 4" or 8" fullrange drivers for a room setup to mate with a SET. Do you have any plans for the project you mentioned above or any other plans? Thanks |
If that the goal might be worth a shot. If you guys want cheap and realy good sound a fostex fe126e in a 3x4ft, 3/4in T. baltic birch baffle, a 2 1/2ft -2ft baffle would also work just bass is reduced .Sounds wonderful can run on low power and is affordable and a very easy build a home center would cut the baffle, a jig saw can cut hole for driver, shelf brackets work great as baffle stands. I use 1 each on back of baffle and slightly lean back this helps with image also couples baffle to floor eliminates most standing waves because of slope and allows one to use just 1 -12in shelf bracket for stands the brakets are pre drilled and a madisound cone fits if one wants. This loudspeaker is time and phase correct has no crossover is also dipole. All for $70 and some plywood brackets etc.Bet you could build a pair in a few hours and this incs time to get ply materials etc. I use shalac for finish this drys fast mins and adds to sound quality.Build a pair you will thank me later. great for SI or tubes- small SS. |
since i'm temporarily bored at work i'll just add that i removed the original tweeters from their faceplate, snipped off the phase thingy, traced a circle from the template onto the faceplate with a pencil, and used a curved file to open the hole carefully until the new tweeters fit snugly into the opening. nice cosmetic result. takes a little while though. kind of like whittling. |
I have three pair of those Parts Express "book" speakers and I think they sound great. They don't have great detail but tonally they are right to my ears. None of the dreaded high frequency tizz.
If someone would come up with a mod kit I would be very interested. |
MD,
That's Awesome! I gotta try it....
TIC |
i have received word that the initial price of the kit will be $19.50 plus shipping. lower than i thought it would be, so it leaves more pennies for dynamat and other tweaks. |
Musicdoc,
Any idea of a possible price range for the upgrade?
Has anyone here that is interested in a cheap DIY project seen the Best Buy Insigna Speaker upgrade performed by Danny Richie at GR Reasearch? Looks way cool for the price. Supposedly sounds really good and cost about $150 total including the original speakers. Check it out:
http://www.gr-research.com/insignia.shtm
If we could just get someone to come up with an affordable upgrade to the "Book Speaker" from Parts Express. It would be WAY COOL to have a totally discrete speaker that sounded decent. Check it out:
http://www.partsexpress.com/pe/showdetl.cfm?&DID=7&Partnumber=319-040
These speakers really do look exactly like a book. They are totally discrete when placed on a bookshelf. Really cool, but don't sound very good. Mine sound better with the tweeters disconnected!
Enjoy,
TIC |
for those of you who may have a pair of these gathering dust in a closet (as i did), and don't mind getting your hands dirty (as i love to do), i have discovered some worth-while upgrades and tweaks that really make a difference for the little presidian.
as some of you have discovered, the cheap "one cap" crossover yields a crossover frequency of about 9 kHz, making the little midwoofer work way too hard. i'm not sure if this has anything to do with wth the lively sound that has resulted in positive first impressions, but for me they got tiring real fast.
anyway, introducing new low and high frequency crossovers (mounted hard-wired on separate boards), along with a new (larger) tweeter make for a much more realistic design with a more detailed and even sound.
the kit i received consisted of the crossovers (four boards with hard-wired components and wiring), two tweeters, two faceplates for the tweeters (although i modified the faceplates from the stock tweeters to receive the new ones), and some unique adjustable internal braces (front to back) to be used between the drivers.
additional tweaks i added myself: i changed the wiring from the crossovers to some kimber tcss that i had lying around. i added dynamat to the inside of the cabinet and also to the stamped woofer basket. lastly i stuffed the cabinets with some lambswool that i also had in surplus. i suppose "acousta-stuf" would be the most logical choice here. i have a few other ideas for "finishing touches" that i haven't employed yet.
now granted, these are cheap speakers to begin with and the mods/tweaks don't make them into totem model one signatures, but they do improve upon them in a most obvious way (to my tin ears that is), and makes them even more of a value IMHO.
DISCLOSURE: i have NO vested interest in this product beyond my own use and enjoyment. i know my post reads like a shill but i suppose my only reply is "there's no greater zealot than a convert" :-) the origin of this kit is my soliciting the developer, who goes by the user id "litekeys" on ebay, after performing his mods on a pair of minimus 7s from the local habitat thrift store. this fellow has sold upgraded crossovers for the old radio shack minimus 7 and 77 for some time now (among other things), and was receptive to the idea of refining yet another budget speaker from the shack. he is a dedicated enthusiast and gentleman. his communications are prompt, polite and detailed.
the final price for the kit will be determined by him, but all of his offerings appear to be high-value. i suggest you contact him directly if interested. i'll likely be modding a second pair over the winter.
be well. |
I pretty much agree with Reubent. I haven't had any cheap speakers since my Spica TC-50's fifteen years ago, but the Presidians would certainly be no match for them with music.
An easy, affordable line array might be a legitimate idea though. or they might make decent cheap center channel speakers - you can by a pair with a friend and have one each for $20! They'd make a lot of sense in settings where you don't want or need a $400 pair but still want decent sound - like in a garage or workshop. |
Studioray,
I bought a pair of these to use for testing and for casual listening in a "portable" system. They are very good for $40 and are decent at 2-3 times that price. However, they do not compare favorably to the $400+ speakers you mentioned.
If you don't need a pair of cheap, disposable speakers, I don't think these are going to "do it" for you.....
TIC |
If the midbass driver is a simple paper-cone would anyone planning on performing the inexpensive dyi upgrades mentioned above consider painting this driver with "Damar Varnish" to stiffen it up a little?? I have used it on other paper cones and felt it was beneficial tweak.
L |
Can someone who's listened to these give me some sort of reference as to just how good they are for the money? I mean I see that it's obvious from the previous posts that they sound way better than their $40 price would suggest... but does that mean like speakers in the $200-$300 range, which I usually find unlistenable, or does that mean these compare favorably to speakers in the $400-$700 range like System Audio SA-205 or Krix Equinox or Quad 11L???
Yeah, yeah - I know that it's only forty bucks so I shouldn't worry about it, but I have WAY too many speakers already and have been on quite the spending spree as of late. Also I don't wanna buy stuff and then return it just in order to get my kicks and giggles to hear it - I don't think that it's very fair to the retailer.
But if there is some way that these speakers really do compete with some of the mini-monitors mentioned above, even if they are a bit less than them performance-wise, then I want a pair. After a good time spent listening and evaluating, they would probably then be put into service as a replacement of the rear surrounds in my stock home theater system. (I've already replaced the fronts and middle with Krix and Celestion and the improvement has been wonderful).
Thanks! |
Just shoved an old t-shirt a few inches into each port and draped the rest over the top and then behind. Makes the upper lows and lower mids much more natural IMO without any effect on the freq. range as far as I can hear. So it's probably worth adding damping to the cabinet and filling the port tube with it. I doubt that the "port" had any audio design parameters involved in the first place. |
I'm waiting for a pair to hit the classifieds. Hopefully Audiogon will have a used bluebook price soon. |
6r4apo001@sneakemail.com..."Coasting along" Exactly what we want to get decent volume without distortion. |
Nrenter's recommendation of side placement with inboard tweeters and toe-in was a good one IMHO. still wondering about upgrading the tweeters though, but need to start doing my homework first. |
Hooked 'em up tonight. First impressions - they are undoubtedly excellent for the price, and may repond to some tweaking or EQ. They image very well, and do have an excellent coherence - which is of course to be expected since they're basically crossoverless. Without having done any measurements, I'd say they're a fair bit forward in the 3.5 k to 4.5k freq. range which is a little fatiguing. The highs are quite good though - these appear to be decent tweeters. The 65 hz low end stated in the specs is a bit of an exaggeration. I don't think they go much below 100 hz, and even there it's pretty rolled off. Plus, I'd say from 100 up to about 300hz is pretty sloppy - not audiophile quality.
My best guess is adding a small sub that could crossover at 120hz to 150hz might make these very affordable monitors for someone on a budget. A stack of 2 per side might help by inducing some coupling in the lower end and altering the effective EQ. I'd also experiment with leaving out one pair of tweeters from the mix. Placement in room corners would definitely help - which I'm not able to do in their current location.
I'll post again when I have time to experiment.
BTW - Mine state on the cabinets "ASSEMBLED IN CHINA" - so there are apparently different manufacturing lots out there (per Eldartford's version). |
Though the total impedance might be 8 ohms, it would require too much voltage to put any decent amount of power to each one; they'd all be coasting along- |
Let's assume that each "element" (speaker, driver, whatever) actually behaves like an 8 Ohm resister.
Let's also assume that we're going to use 16 elements (instead of 14). It makes the math easier.
We need to recognize that resisters in series are simply additive:
R(1) + R(2) = R(3)
But resisters in parallel are not:
1/R(1) + 1/R(2) = 1/R(3)
So we'd arrange the elements into serial groups that are parallel to each other in attempt to keep the total resistance in an "ideal" range (around 8 Ohms).
If we used 16 speakers, we'd create 4 groups of 4 speakers and wire each of those 4 groups in series:
S(1) + S(2) + S(3) + S(4) = G(1) = 32 Ohms
S(5) + S(6) + S(7) + S(8) = G(2) = 32 Ohms
S(9) + S(10) + S(11) + S(12) = G(3) = 32 Ohms
S(13) + S(14) + S(15) + S(16) = G(4) = 32 Ohms
Now wire each of those groups in parallel:
1/G(1) + 1/G(2) + 1/G(3) + 1/G(4) = 1/Total = 8 Ohms |
when i found my vintage hartley monitors, the crossover was the same, a single cap to an older cone tweeter with the mid-woofer running "wide open." the response of my friend who dabbles in speaker design was "ugh." the new tweeters and crossovers from hartley have three components (now four, i added a bypass cap), and the sound is now very acceptable to my tin ears. a similar upgrade for these little puppies naturally springs to mind.
funny about the deCapos and the use of language. sign o' the times...... |
Drubin,
I own the Ref. 3A DeCapos and these Presidians. There is no confusing the two! BTW, My Decapos which supposedly "have a single cap" on the tweeter, actually have 4 components in the crossover. It's strange: When I enquired with Divergent Technologies (Distributor for Ref 3A) they said there is "effectively" a single cap on the tweeter. Whatever that means!
Enjoy,
TIC |
I'm thinking about trying this arry idea. I don't know much about arrays. I guy at work says that 14 per side wouldn't work. He says you can't wire them in series as it would double the ohms every speaker, etc.
I don't understand what in the hell he's talking about. Would someone mind explaining it to me and how I should hook these up together.
Thanks
Pete |
What's the sensitivity on these. Anyone try them with a Sonic Impact amp? |
I just gave these a listen. I'm very impressed. |
Mounting both drivers on a planar surface yet featuring a first-order crossover on the tweeter and no crossover on the mid-woofer is no doubt a feature designed to help optimize placement. If the speaker is placed horizontally (with the tweeter closer to the center) a slight toe-in will time-align the drivers. You'll know when you've hit the right amount of toe-in when the image "snaps" into focus. I'm almost positive this is what Rat Shack intended.
Bring on the 7 1/2' array!!!
So what are we gonna use for the bottom octive-and-a-half? |
depending on the brand of speaker, i guess the one cap crossover could either be considered "elegant" or "cheap." maybe a little bit of both in this case? |
Lack of an inductor in series with the woofer means that they rely on the limited frequency response of the woofer to roll off its HF response. This means that the woofer must not exhibit any wild peaks and dips as it approaches its HF limit. The purpose of the low pass section of a crossover is to keep the woofer signal away from this eratic frequency range. So the success of the full range woofer depends on the characteristics of the driver. A light cheap paper cone is more likely to work well than a metal cone driver, although the metal cone is far superior if properly used. |
>only a single 1 Microfarad capacitor on the (+) tweeter lead, so the mid-woofer is running rull range.
This makes them a similar design to Reference 3A. First-order crossover, correct? I imagine the drivers are not physically time-aligned, but that shouldn't matter much. Effectively no crossover, which approach always seems to deliver some sonic benfits as well as some problems. |
midrange clarity improving with break-in. it's faults continue to be eminently forgivable at this price! a fun little speaker, especially enjoyable with acoustic jazz, folk etc. |
Picked up a pair yesterday just for fun. If they sound decent I'll pick up a 2nd pair and try stacking them. I'll report back when I play around with 'em a bit.
ALso - The floor models in the store simply say "Made in China" - nothing about assembled in USA, so I'm wondering if (per Eldartford's info) there are already different manufacturing lots to be aware of. I haven't opened my box yet, so don't know about those. |
I'd be very wary of this speaker. I took a look at the tech specs and it very clearly states that the only language supported was English. So if you're into any opera, world music, foreign films, etc. this is NOT the speaker for you. I guess to keep the price that low they eliminated the Universal Translator circuits. |
No JQ??? How can we have any fun?
He's the only group member that's not uptight about all this audio stuff. How old is he now, five? :^). |
I could use a project like this - it would be a nice break from M&A case analysis. If you're seriously up for this one, shoot me an e-mail. JQ will stay at home this time. |
Come on over Nick, lets put them together.
The only requirement is you bring your kid to help. He was a blast when we were working on your turntable. |
