Page 22 of 22 FirstFirst ... 12202122
Results 316 to 329 of 329

Thread: Bgw amp plus eq for free!

  1. #316
    Senior Member RMC's Avatar
    Join Date
    Feb 2017
    Location
    Canada
    Posts
    994
    Sea,

    Since you have a history of stashing treasures in the house, i wouldn't mind having a peek at the connector box you have somewhere. Could be some nice stuff to see in there. No obligation, feel free to say no. Just curious.

    Widget,

    Thanks for the input. In spite of that i still like Switchcraft, they have some quality connectors, manufacture in the US, have a huge selection of connectors and adaptors, covering almost any situation, not really matched elsewhere. Hopefully they won't end up pricing themselves out of the market (or may become a niche mfr?). That would mean about Neutrik, Senior, Amphenol? and China left. And Neutrik has already started cutting cost with quality going down a little...

    Richard

  2. #317
    Senior Member RMC's Avatar
    Join Date
    Feb 2017
    Location
    Canada
    Posts
    994
    Neutrik's well-known NC3FX Female XLR connector of more recent construction. Right there near the top can see the O ring has been changed for a grey one, previously was black. Not just a matter of color, also cheaper. If you look at the previously posted pic in # 295 (Aphex interfaces cables made), using some of the Swiss made connectors on-hand, the XLR O rings are black.

    Name:  IMG_1825_LI.jpg
Views: 244
Size:  132.8 KB

    In addition to the O ring, the soldering cup terminal (2nd part) was also changed from round to squareish and the metal color isn't as shiny silverish as in the past. Looking at the other end of that part, where the three male pins go in, it use to be almost 360° full metal inside for increased contact. Not anymore. Think of tiny prison bars where you have a metal bar/strip then free space, again metal bar/strip followed by small space, and so on all around. So less metal used for contact inside each pin hole. Material cost i guess. The cable retainer (3rd part) is the newer model, and not as robust for sure as it used to be. Therefore four more cost reduction small modifications...

    Name:  IMG_1828.jpg
Views: 257
Size:  214.0 KB

    The other well-known NC3MX male XLR connector of more recent times. Note on the 3rd part shown the silver soldering cup terminal and to some degree on the three pins. This is typical older style. But Neutrik has changed such thing on recent XLRF. Then i assume the XLRM might be the next one in line for a cost reduction "remodeling". The cable retainer (4th part), same as dealer gave me to replace a lost one, is also the recent model with weaker plastic.

    Name:  IMG_1861-2.jpg
Views: 254
Size:  169.2 KB

    I made sort of a global recap picture, it should follow soon, showing the changes between older and newer Neutriks, for their long standing and most popular models i guess: NC3FX (XLR female); NC3MX (XLR male); NP3C (1/4"TRS). The NP3X 1/4"TRS is excluded since its already been shown/compared with the NP3C, plus the former has limited barrel space re cable size.

    Connectors are a details business in my view, and these add-up, plus details matter for long-term connection reliability, specially when systems are subject to setup and tear down a number of times.

    Richard

  3. #318
    Senior Member RMC's Avatar
    Join Date
    Feb 2017
    Location
    Canada
    Posts
    994
    These are the connector changes recap pictures mentioned in the previous post. Two pics are identical, except for where i've drawn lines to point where modifications were made. Third pic is simply taken from a different angle that some folks may prefer. Note the first pic is clear enough to be enlarged a few times (i tested it), in order to have a closer look at the differences, after saving it to hard disk.

    The left column is Swiss made connectors all the way down, and the right column is newer Liechtenstein made equivalent parts. 4 parts per connector, each time in the same order from top to bottom. That makes it easier to compare two generations of the same connectors, also gives members a more global view.

    At far right the packaging with model number is used for connector identification purpose right next to the one involved. There's a number of parts there making it preferrable to know which one belongs where.

    Note the change mentioned in previous post re inside the female XLR where the male pins go in is not show here, could not picture that with the small cam i have, but i sure see that change with my eyes and a good light.

    The vertically drawn line in the right column is to indicate the change made on the female XLR soldering terminal has not been carried out YET on the male XLR soldering terminal a little below. Hence a difference between these two connectors. But i wouldn't be surprised the same mod makes its way to the male XLR in the near future. More to come.

    Richard

    Name:  IMG_1901.jpg
Views: 216
Size:  75.9 KBName:  IMG_1901_LI.jpg
Views: 221
Size:  78.5 KBName:  IMG_1903.jpg
Views: 210
Size:  76.4 KB

  4. #319
    Senior Member RMC's Avatar
    Join Date
    Feb 2017
    Location
    Canada
    Posts
    994
    Unfortunately don't have many Swiss made Neutriks left, having used recently four 1/4"TRS as well as XLRF from my stock to make cables for the Aphex interfaces.

    Pic: left bag XLRM, these are pretty old, bought them used in nice condition long ago, were soldered once, built like a tank, their silver metal wasn't as shiny in those days as the bit more recent ones on the right side, also Swiss; a few 1/4"TS follow; then a pair of 1/4"TRS & XLRM. The odd number (3) of XLRF at far right is due to a mic cable i have, which had a Neutrik XLR connector at one end and a Switchcraft XLR at the other end, i kind of think it looked dumb to have different brand connectors on the same cable, so replaced the Switchcraft with a Neutrik, "symmetry" restored, and a working XLRF Switchcraft now orphan...

    When these Neutriks are depleted will have to say goodbye to good old Swiss Made connectors, sniff. Welcome to the world of cost cutting and quality reduction, like most of the rest...

    Name:  IMG_1848.jpg
Views: 204
Size:  73.1 KB

    Recently purchased a whole bunch of new generation Neutriks i'll need: NC3FX, NC3MX and NP3C (plus the two NP3X to try). The details about those were shown before. As for the odd number (15) on the left bag here this is caused by having to replace (make a pair) the XLRF i took in my stock in order to put a Neutrik connector on the mic cable mentioned above.

    Next time different connectors, no Neutriks!

    Richard

    Name:  IMG_1843.jpg
Views: 208
Size:  84.2 KB

  5. #320
    Senior Member RMC's Avatar
    Join Date
    Feb 2017
    Location
    Canada
    Posts
    994
    At the top of pic is the orphan Switchcraft A3F XLR female. As explained before i removed it from a mic cable simply for appearance reason. Its used, in good condition and works. IF YOU HAVE SOME USAGE IN MIND FOR THAT A3F, LET ME KNOW, ITS AVAILABLE FREE. Won't be using it in a foreseeable future, keeping it in a bag, and don't like to throw away things that work and may be useful to someone else.

    The first four bags from the left are Senior connectors. Purchased these a long while ago when Senior was distributed in Canada. I've seen somewhere Senior was founded by a group of ex Switchcraft employees. No wonder their 1/4" look similar to Switchcraft models 280 & 297 shown before. Senior now being amalgamated into Maclean Senior industries.com (MSI). Though their 1/4" look like older Switchcraft, their XLR ones look more like the Neutriks.

    Nicely made connectors: 1rst bag new 1/4" TRS; 2nd bag also TRS bought new, but i soldered those once before then made changes to some cables, kept the connectors as used ones; 3rd bag new TS; 4th bag new RCA's. The last two bags on the right are connectors with a soft spring at cable entry, nice to reduce foil shield cable bending in tight spaces. Don't recall their origin. The spring 1/4"TS are used to connect the Alesis reverb & delay to the mixer (pics and explanations later).

    Name:  IMG_1849.jpg
Views: 196
Size:  82.5 KB


    The idea here is to use some spring loaded RCA's along with the small & shorter Canare install cables left in order to replace the larger & longer Monster Cables (previously shown) going from Bellari phono pre to Aphex interface. They'll fit better in the limited space available, while providing a softly curved cable using that RCA model. On to do list for next time i make cables, will solder those too.

    Richard

    Name:  IMG_1859.jpg
Views: 201
Size:  66.9 KB

  6. #321
    Senior Member RMC's Avatar
    Join Date
    Feb 2017
    Location
    Canada
    Posts
    994
    The connectors used on cables between the Mackie mixer and the Alesis effects unit are somewhat different from what i usually use, and a few reasons will explain this further in next post.

    On 1rst pic the top cable uses a pair of Senior 1/4"TS, while the other two cables in the middle have spring entry 1/4"TS connectors. The logic for using spring 1/4" has already been explained. As for the use of Senior connectors here, have only two spring 1/4" connectors left, shown on a prior pic, and want to keep them as spares, in case there's a problem with the ones in use, plus the Senior i have a bunch of them.

    The odd number of cables (3) seems unusual for stereo operation, and it is stereo, but for the moment simply keep in mind the "going out in mono and coming back in stereo" connection principle between the mixer and effects.

    Name:  IMG_1856.jpg
Views: 189
Size:  82.8 KB


    Older folks here may remember this Alesis unit since tons of them were sold and it was known as the affordable, quick and easy reverb & delay. Alesis has typically been musician's gear, not really professional studio equipment in my view, though they called themselves "Alesis Studio Electronics", maybe more for project studios i guess. 25 years ago it cost me $290.CAD

    That sound effects tool may not be the taste of today but still quite useful to me and its been reliable since 1995. A fun toy to play with! Every setting is right there at the finger tips, fast to make sound effects changes on the go, without having to enter menus, scroll, select, confirm, exit, etc.

    In addition to adjustments & EQ knobs, the two main knobs at right let the user determine the effects, the first one to choose among 16 program types (reverb, delay, etc.), with the second one covering 16 different program variations. For example, if "large rooms" is selected, there are 16 types of large rooms available. And so on for other effects. A card, plus owner manual, provide identification details/explanations for each effect in case the user requires more info.

    Note that you don't necessarily need a mixer to use a sound effects tool such as the Alesis. It can be used in the audio signal path between a preamp and amp, for example. But in such case its operated full (L/R) stereo with the whole program material being subject to the effect applied. Small room #1 acts as defeat setting (no effect).

    First Alesis pic is pretty clear to be enlarged somewhat, however the next one is even better.

    Back to "going out in mono and coming back in stereo" with upcoming post.

    Richard

    Name:  IMG_1913.jpg
Views: 189
Size:  65.3 KBName:  IMG_1942.jpg
Views: 189
Size:  74.5 KB

  7. #322
    Senior Member RMC's Avatar
    Join Date
    Feb 2017
    Location
    Canada
    Posts
    994
    The three-cable connection scheme for "going out in mono and coming back in stereo" applies to signal routing between a mixer and effects device. Note the purpose isn't to save money on cable & connectors, though it does happen as a small bonus, but rather for keeping some mixer flexibility or possibilities.

    A shortcoming small mixers have is the limited number of Aux Sends/Returns to do this, therefore one needs to optimize use of these resources. Some very small mixers have only one Aux Send/Return, in such case there isn't much choice, you have to use the sole connection possible and you're done. The case here is about using 1 or 2 mono Sends, and a stereo Return, on mixers having a pair of each, like the one shown which is pretty frequent.

    A number of smaller mixers have two Auxiliary Sends and two Stereo Auxiliary Returns. An Aux Send can be used to feed a stage monitor/headphones (foldback as the British call it) or an effects processor, while a Stereo Aux Return will take the processed signal from an effects unit, or may be used as an additional stereo input, for example.

    The Alesis effects is full stereo but allows feeding it in mono and will still output in stereo. Which is nice to avoid using all Aux Send possibilities with a single device, therefore keeping the other Aux Send free to connect something else the user may need.

    So exiting mixer in mono to effects unit and returning signal from effects to mixer in stereo implies one cable (mono) Mackie to Alesis and two cables (stereo) from Alesis to Mackie mixer. Hence the use of only three cables as shown on a previous pic.

    One can still output mixer in stereo to effects unit with a fourth cable, if that is the wish, using the two available mono Aux Sends (one per channel) and use a Stereo Aux Return on the mixer. The drawback with this option is simply that you have no other Aux Send left for monitor (add small fourth cable cost). Therefore, having mono out/stereo back in is a nice alternative and makes sense to save the next Aux Send on-board the mixer for other use.

    Richard

    Name:  IMG_1915_LI.jpg
Views: 171
Size:  58.5 KBName:  IMG_1917_LI.jpg
Views: 179
Size:  102.9 KBName:  IMG_1936_LI.jpg
Views: 180
Size:  90.6 KB

  8. #323
    Senior Member RMC's Avatar
    Join Date
    Feb 2017
    Location
    Canada
    Posts
    994
    Name:  IMG_1945.jpg
Views: 176
Size:  64.2 KBName:  IMG_1948.jpg
Views: 173
Size:  77.4 KBName:  IMG_1949.jpg
Views: 172
Size:  84.5 KB

  9. #324
    Senior Member RMC's Avatar
    Join Date
    Feb 2017
    Location
    Canada
    Posts
    994
    PHASE

    Didn't want to change the purpose of Olaf's thread in DIY section which is about amplifiers capable of dual woofers, so decided to post the phase related material in my own thread. As mentioned earlier in the other thread, Dickason says phase is generally a not well understood concept, therefore may be worth some explanations.

    I don't have time to re-type all the texts so consider the following pics as my quoting of these.

    J. Eargle: short and clear, but does not provide much further details.

    "The phase angle, measured in degrees, represents the deviation in driver output phase response relative to the input signal. Group delay is another way of viewing this, in terms of actual output signal delay. (Loudspeaker Handbook, 2nd ed., p. 66, 68)

    Talking about EQ "... minimum phase; that is, the phase shift associated with a given amplitude correction is minimal, ..." (J. Eargle, Handbook of Sound System Design, p. 215) Keep this one in mind since further Dickason refers to minimum phase.

    Dr. Tempest: simple and interesting explanation

    (Dr. W. Tempest, Sound Waves, in Audio & Hi-Fi Handbook, 2nd ed., Edited by Ian R. Sinclair, p. 24-25)

    Name:  IMG_1961_LI.jpg
Views: 96
Size:  76.7 KBName:  IMG_1963_LI.jpg
Views: 94
Size:  64.8 KB


    Dickason: more detailed and technical than the others

    (Vance Dickason, The Loudspeaker Design Cookbook, 5th ed., p. 138-139)

    Dickason also has two graphs illustrating his words making it even easier to follow, however copying his "artwork" here would be a more sensitive issue with regards to copyright matters, contrary to wording.

    Richard


    "Phase of any magnitude waveform is a function...
    Name:  IMG_1966_LI.jpg
Views: 95
Size:  88.3 KB

  10. #325
    Senior Member RMC's Avatar
    Join Date
    Feb 2017
    Location
    Canada
    Posts
    994
    New Year contribution to the community. And Best Wishes to all for 2021! Lets hope its a better one...

    Posting in my thread this reply to LPAD subject posted elsewhere, since this is late, plus its fairly long. Based on the idea that any help/relief should be welcome by audiophiles considering fixed Lpad trial/error is a hassle... The text is split in 5 posts.

    Context: As i remember, a member wants to reduce driver sensitivity with an Lpad, he's not sure how to go about it. Rob suggested purchasing some rotary ones from Parts Express and then measure values when he's found the proper level. Didn't know that trick. However, the member decided instead to purchase an assortment of resistors, for trial/error i assume, on R1 and R2 of fixed pad.

    I can understand he may not want to purchase variable Lpads possibly not needed after measuring. On the other hand, getting a resistor assortment might not be required either for trial/error method. Trying different combos of series and parallel resistors, connecting both and undoing each time to test others is time consuming.

    The following could be a simpler and cheaper way to address the problem, it is derived from Dickason (note 1) and Weems (note 2). Main question remains how many db reduction should be applied for proper driver sound level blending. Some resistor testing still needs to be done, though less of it, using Weems procedure. Reducing the guess work and cost using only one series ceramic resistor at a time (instead of two, R1 and R2) plus doing a little and simple math (divide twice, multiply once, then one log) looks appealling to get it in the ballpark.

    From Dickason, in Driver Attenuation Circuits:

    "... you can use two types of attenuation circuits: either a simple series resistor, or an L attenuation network like the one illustrated in Fig. 7.106. A series resistance is adequate so long as you refigure the crossover components to account for the increase in total driver impedance." P.120 (RMC:Weems says pretty much the same thing P.90)

    Have done the single series resistor trick before in 2-way satellite boxes, not only to reduce tweeter sensitivity but also reducing at the same time the power sent to tweeter (having little higher impedance). This because the 6 db xo frequency used was a bit lower than ideal for driver protection and the lesser power due to resistance helped. They never failed, hit two birds with one stone.

    Here the series resistor is used only to get an idea, from Weems' basic math, of the db reduction number it would allow. First you need to try some single series resistor (e.g. 1, 2, 3 ohm) with the driver to determine which one reduces sound level by the right amount. Take note of resistor impedance that delivers this. In my trials only a couple of resistor values had to be tested (not a whole bunch) to hit the desired blending sound level.

    Exercising judgement/logic in the choice of resistor values to test shortens trial/error work (less trials). If you have no clue where to start, or about the relevance of a potential resistance value, take that number, with driver impedance, and run the data in Weems' simple math presented below. In that case you won't know sound wise if its the right resistor or not, but at least you'll get a minus db amount the resistor provides, which may help in deciding if its worth testing it or not. A large or tiny amount minus db may be too much/little for a first try.

    Testing can be done by ear (subjective) or with a Sound Level Meter (more objective). After resistor test(s) are done, since you have resistance's value, as well as the driver's original impedance, you can insert the numbers in Weems' calculations not only to get the minus db number to apply, but that one also makes fixed Lpad tables much more useful, since they're presented by db loss figure sought with the corresponding R1 and R2 values.

    Assessing the db number to subtract to match other driver(s) sensitivity to your liking should be easier than it is, and still requires some time. Unfortunately, you get nothing for nothing... Hopefully the above will help members with another possible way in dealing with Lpads. Regards to all,

    Richard

    Note 1: Vance Dickason, The Loudspeaker Design Cookbook, 5th Edition.

    Note 2: David B. Weems, Designing, Building, and Testing Your Own Speaker System, 4th Edition.

    EDIT: Later saw the OP mentioned "Since I don't have those pads I just want to avoid having to perform trial and error more often than necessary..." Agreed.This in my view confirms the pain in the butt of trial/error with R1/R2, and the necessity of trying to reduce trial/error process as much as possible, while minimizing expenses.

  11. #326
    Senior Member RMC's Avatar
    Join Date
    Feb 2017
    Location
    Canada
    Posts
    994
    The calculations/examples page for driver db reduction using a series resistor

    From Weems, Useful Formulas, Ohm's Law for Speakers

    " E = I X Z; I = E/Z; Z = E/I; E voltage in volts; I current in amperes; Z impedance in ohms; worked example:

    An 8 ohm resistor is put in series with an 8 ohm tweeter. How much is the sound level reduced? Assume any drive voltage that is convenient; for example, 16V. The nature of the speaker's impedance depends on the frequency, so we will assume that it is purely resistive.

    Then I = 16/16 = 1A

    The voltage across the speaker is: E = 1 X 8 = 8V

    Before adding the resistor, the voltage across the speaker was 16 V. So the ratio of voltage in the new circuit to the old one is: new voltage/old voltage = 8/16 = 0.5

    The db/voltage ratio chart tells us that for a voltage ratio of 0.5, the output is down 6 db." (P. 160)

    " To calculate any voltage ratio: db = 20 log E1/E2 " (P. 168)

    The way its explained is not stellar, particularly for the multiply above, however i'm adding another example below with some further details.

    Weems' approximate voltage ratio chart with db loss (P.168) has not been reproduced here, nor a sketch, because there's too much typing involved, plus some copyright issues may then invite themselves here... However, the simple 20 log equation above for db reduction does provide the exact number, whereas Weems' chart gives close but approx. results.

    Other example:

    Use of a 6 ohm tweeter, a 2 ohm series resistor is added to reduce its sensitivity, drive voltage is 2V. How many db reduction will this lead to?

    I (current) = E/Z = 2V/8 ohm = 0.25A (8 ohm impedance here is made of 6 ohm tweeter + 2 ohm series resistor)

    E (voltage) = I X Z = 0.25A X 6 ohm = 1.5V (this voltage applied to 6 ohm tweeter alone, no resistor connected)

    To calculate the voltage ratio in the present circuit (1.5V) vs in the initial circuit (2V): present voltage/initial voltage = 1.5V/2V = 0.75

    According to Weems' voltage ratio table, a 0.7 ratio corresponds to a minus 3 db reduction. I calculated just above a 0.75 voltage ratio, pretty close to 0.7, so my example should give about minus 3 db also. Lets check this with the formula: db = 20 log E1/E2; solving the two voltages first, then the log (base 10), finally multiply by 20. Result: -2.5 db. A 0.5 db difference with the table, close but shows the table's approx. nature, whereas the formula is exact.

    Richard

  12. #327
    Senior Member RMC's Avatar
    Join Date
    Feb 2017
    Location
    Canada
    Posts
    994
    Some additional Lpad notes

    The Lpad tables I've seen all appear to assume the speaker is a resistive load. There are many fixed Lpad tables on the Net, but prefer using those from known sources like Eargle or the more detailed and sophisticated on R1/R2 power ratings from Drew Daniels/JBL. The latter's decimal numbers almost guarantee you won't find such resistor values in store, so you'd get the closest ones you find.

    For testing purpose 10 watt ceramic resistors should be enough with normal listening level, though at least 25 W units be preferrable for longer term higher power. Drew Daniels specifies in an example a R1 33W and R2 67W! with a 100W power amp! Plus the sum of the power ratings of the two resistors should equal the amp's power rating. Using resistors with such power ratings is unlikely to happen in my case, local electronics store sells 5W, 10W and 25W... Wonder if other members do find and use those high power ratings?

    BTW with rotary Lpad adjustments some would start with it tuned up fully and then decrease the level to pleasing or correct level. Weems recommends to go the other way around: turning it all the way down, then increasing it progressively up to the point where the level balances/blends ok with others. Might seem like the same thing? I don't think so. I can see a reason related to psychoacoustics (perception of sound), too long to explain here.

    Richard

  13. #328
    Senior Member RMC's Avatar
    Join Date
    Feb 2017
    Location
    Canada
    Posts
    994
    Sound Level Meters used for db reduction assessment

    Left: In the old days if you didn't have deep pockets for B&K equipment, this Radio Shack analog Sound Level Meter was the one used by many audiophiles. It deals with sound levels from 60 to 120 db, up to about 8-10 khz. Bought it new about 30 years ago, checked it again before taking this pic and still works well. Not bad for an oldie. VU meter shows forgot to change it from battery check mode to SLM mode at time of picture taking...

    Right: Newer generation digital model, naturally more precise and have better specs, can do 35 to 130 db, going up to 8khz (my tweeters are already active well before that limit, not using super tweeters). In order to assess a MF or HF driver output level you don't really need such large db range, SPL like 85-90 db is probably enough for most.

    Richard

    Name:  IMG_1997.jpg
Views: 56
Size:  84.0 KB

  14. #329
    Senior Member RMC's Avatar
    Join Date
    Feb 2017
    Location
    Canada
    Posts
    994
    Temporary crossover board for testing

    Crossover simulation done years ago on a leftover piece of 3/4" plywood. The exact one used to try various resistor values to reduce tweeter output and power sent to driver. Board doesn't need to be fancy for a temporary crossover used only for tests. Wood isn't fragile nor a current conductor. Another oldie i kept.

    Quick randomly placed a couple of screws and parts on that board just to show the retaining/connections principle. No soldering at all, easy on and easy off to sonically test different part values. Component's electrical joints are done under the screw heads. No need to drill screw holes, simply making a small pilot hole in wood with a metal pic shown at right. 1/2" long screws or so are driven in about half way, being used to circle part wires around screws. When XO assembly is done get the screws in all the way. To try another resistor in the same position, simply loosen relevant screws to unwind part wires. Parts hold well, never had a connections issue.

    If the terminal cup wires on a speaker cab are long enough, as well as those leading to drivers, or can be extended, route that wiring out of the cab through a vent hole and place the temporary xo on the floor in front of enclosure for easy part access and resistor replacement. Install drivers on enclosure therefore closing the box and you're ready to start testing.

    Richard

    Name:  IMG_1994.jpg
Views: 54
Size:  72.4 KB

Thread Information

Users Browsing this Thread

There are currently 1 users browsing this thread. (0 members and 1 guests)

Similar Threads

  1. Free and new to me!!
    By mrbyl in forum Lansing Product General Information
    Replies: 4
    Last Post: 06-05-2010, 01:21 PM

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •