Next figure shows the 2nd and 3rd order harmonic distortion with an output of 96db at 1 m. A means of solving this problem was presented by dappolito 3 wherein a. Iow a realworld, 1st order dappolito doesnt have flat offaxis power response unless the drivers somehow do also. Well if you asked joe what his d appolito design is, he would tell you that he made the mtm design to reduce lobing and improve midrange output on a standard 2 way.
On a recent exchange with joe dappolito, we asked him if he had. One can sidestep most of the pain and suffering their fellow enthusiasts will endure in the wild. A d appolito design has a loop that is pointing straight at you. Ive looked at the dappolito configuration on some kef, tannoy and. There are certain dispersion advantages with a d appolito design that a conventional design does not share. The basic dappolito configuration consists of an array of a single tweeter flanked by two woofers, one above and one below and driven in parallel from a single. Dappolito on what matters audiogon discussion forum. He also pioneered the extremely popular d appolito woofertweeterwoofer driver configuration, seen in many successful loudspeakers systems.
The horizontal spacing is good and gives the engineer a big hotspot for listening. Dec 27, 2015 my favorite d appolitoline array set up. A dappolito configuration consists of two woofers and a tweeter in between, or rather a woofertweeterwoofer configuration. Feb 24, 2010 here is joe d appolito discussing his design at an event held at audio video design in newton, ma. Testing loudspeakers is the first comprehensive and solidly authoritative account of just how loudspeakers may be reliably tested. Ultimately, accurate results from testing will lead to better designs. Faceplate for scanspeak d2905 d2904 tweeter truncated shape. Unfortunately, the tl has not enjoyed wide commercial popularity due to the. Now, with a vertical dappolito arrangement you can sorta cheat this and actually use these distances per side so woofermid and midtweet spacing should be 16. A traditional mtm dappolito speaker with both midwoofers operating across the same frequency range has some significant response issues in a horizontal configuration. Pseudo dappolito configuration by towering two pairs of same.
Before i purchased them, i looked into the rs4s which had the same type of drivers, only instead of a tweeter sandwiched between two midrange drivers, it had one tweeter mounted above one midrange. A traditional mtm d appolito speaker with both midwoofers operating across the same frequency range has some significant response issues in a horizontal configuration. You need to pay attention to centretocentre spacing of the drivers vs wavelength over the crossover region. Feb 24, 2010 joe d appolito of mcintosh labs and john mickelson of audio video design discuss the look of the speakers in a room and how to balance art and technology. In the mtm arrangement the loudspeaker uses three drivers. Ideal for applications requiring minimal driver spacing, e. Keele has presented and published over thirtyfive technical papers on loudspeaker design and measurement methods and other related topics, among them the paper for which he won the aes publication award, lowfrequency loudspeaker assessment by nearfield. For a driver mounted in an infinite baffle the limit is f 4311 max d here f max is in hertz and the driver diameter, d, is in inches. The mid and highs would be horizontal as normal, but the 12 inch 8ohm woofer replaced by. Measuring loudspeaker lowfrequency response by joe dappolito.
Depending on the exact implementation the speakers can be positioned with a vertical andor horizontal orientation. Jul 31, 2008 as snells chief engineer, dappolito will now direct all new product development peabody, ma, july 30, 2008 snell acoustics, a leading manufacturer of highperformance loudspeakers for more than 30 years, today announced that legendary audio designer joseph dappolito, ph. This soontobeclassic clearly explains the proper way to acoustically test and measure a loudspeaker. Is there some general rule like you want the distance between the center of the drivers to be no more than the length of the smallest wavelength. If you prefer more laid back speaker response where the drivers and.
This is also known as a dappolito array, since this configuration creates. In free space, a small re bass wavelengths source must deliver constant air. His thor design uses an midtweetermid mtm driver configuration, also known as a dappolito. Thanks all for the great discussion on the d appolito configuration. Focal jmlab grande utopia mint condition fullrange. Another potential issue with the dappolito approach is phase cancellation between the two midbass drivers in the offaxis response, causing interference nulls at different angles, depending on the frequency and driver spacing. The dappolito design, more commonly referred to as mtm configuration in the. If you go back to joe d appolito s 1983 audio engineering society paper, he discusses and analyses the characteristics of a few very specific arrangements of driver spacing, crossover frequency and crossover filter slopes, and i think that has led some to believe that an mtm speaker is only truly a d appolito speaker if it incorporates one of those specific details. Also, take a look around at a huge variety of commercial designs. Naturally, this is a realworld speaker, and to me, the design tradeoffs are well chosen. Dappolito arrangement this loudspeaker arrangement involves placing the medium range speaker and woofer vertically above and below the tweeter with equal spacing. The dappolito configuration has a much wider offaxis reproduction hence it is better suited for loudspeakers thatll be used in either a vertical or horizontal orientation. You can play loud with them but also on low level listening they stay very detailed. There is a question to be asked with dappolito speakers, that have the critical midrange handled by two drivers.
I have some older heresys and was thinking of using one to build a custom d appolito center. Occam audio mtm4 kit b option a fantastic small speaker. The reason dappolito now prefers 4th order filters is exactly why they di monitors have horrible vertical response above 1 khz. Joseph d appolito has a speaker arrangement named after him, a vertical array of midwoofer, tweeter and midwoofer. The nova features a powerful fivedriver design in a wifibluetooth. Mtm driver spacing techtalk speaker building, audio, video. Dappolito spacing techtalk speaker building, audio. The only way to get a speaker like that to work well, is to run one of the midwoofs only for bass, so that you do not get a lot destructive inference between the two. If they specified the crossover frequencies and slopes and we knew the driver spacing, we. Apr 12, 2016 dappolito is a contributing editor of speaker builder magazine, but is best known in the business for a driver configuration he originated and which is appropriately named after him. Who can explain dappollito speaker alignment theory in plain.
The company recovered in 1985 but focused mainly on headphones for which was. If using dappolito with a single listening position you can tolerate a little wider spacing because the narrow. D appolito noted that by using a central tweeter flanked by a pair of woofers, such lobing could be minimized. Virtual systems let the world see what youve built. The midwoofertweetermidwoofer loudspeaker configuration called mtm, for short was a design arrangement from the late 1960s that suffered from serious lobing issues that prevented its popularity until it was perfected by joseph d appolito as a way of correcting the inherent lobe. The proteus to d appolito or not to d appolito, that. This arrangement is also known as a midbasstweetermidbass mtm configuration, and the symmetrical interaction between the wavefront from the two midbass drivers and tweeter results in a primary axis which is perpendicular to the baffle. The basic d appolito configuration consists of an array of a single tweeter flanked by two woofers, one above and one below and driven in parallel from a single lowpass network.
Stealth acoustics to debut stingray 83 speaker for euro market. So there is a degree of clarity that exists that the other design cannot match. Apr 29, 2005 i was just wondering what are the advantagesdisadvantages of this type of driver arrangement on a speaker. Dappolito spacing techtalk speaker building, audio, video. D appolito is a contributing editor of speaker builder magazine, but is best known in the business for a driver configuration he originated and which is appropriately named after him. Yet, im sure ive seen commercial designs with 2 or more woofers in a non. Especially the part about cheap drivers sounding better in d appolito configs than standard alignments, which again likely has something to do with d appolito s isolating the dispersion of the driver, and choppy dispersion patterns are a typical problem with poor drivers.
For them to be free of any type of problems, the two drivers that are doing the same job, have to be 100% ts matched and work in absolute unison to be effective in producing those midrange frequencies as good as one driver can do. The only way to get a speaker like that to work well, is to run one of the midwoofs only for bass, so that you do not get a lot destructive inference between the two drivers in the mf range think of it as a 2. The d appolito speaker design is the mtm speaker design. The original thor transmissionline design was published in may 2002. Apr 01, 20 while the driver layout of these speakers is sometimes called a dappolito array, few of them fit the criteria of the originator as to driver spacing, crossover frequency, and final response. They use 2 sets of dapolito drivers front and rear i know there are. Appolito, who is worldrenowned for his pioneering work on mtmbased midtweetermid loudspeaker configurations. With this exceptional design for some exceptional drivers by an excep tional designer. D appolito s solution is to employ two bassmid drivers, one on either side of the tweeter, with thirdorder 18dboctave crossover slopes. If you go back to joe dappolitos 1983 audio engineering society paper, he discusses and analyses the characteristics of a few very specific arrangements of driver spacing, crossover frequency and crossover filter slopes, and i think that has led some to believe that an mtm speaker is only truly a dappolito speaker if it incorporates.
For closedbox or ported systems with finite baffles this limit may be slightly lower. Truncated faceplate for scanspeak d2905 and d2904 series tweeters. Advantagesdisadvantages of dappolito audioholics home. A loudspeaker configuration developed by and named for joe d appolito, in which a high frequency driver, or tweeter, is positioned between two midrange or low frequency drivers that each cover the same frequency range.
Faceplate for scanspeak d2905 d2904 tweeter truncated. An mtm, on the other hand, can obviously use any crossover and each will result in different polar and power responses, with at least the even order systems giving the nulls above and below the centerline. With this exceptional design for some exceptional drivers by an exceptional designer, transmissionline ownership is well within your grasp. Yes, i get that dappolito array is different, but as far as the woofer to woofer spacing and lobing, along with the integration to the drivers, they are the same problems. Joseph d appolito, contributing editor for speaker builder magazine. Simply ignore the silly nomenclature and grandstanding portions of the book. Mtm driver spacing that rule of thumb is intended for any drivers producing similar frequencies at similar levels, such as a woofer and a tweeter at the crossover frequency or a woofer and a woofer in an mtm over all frequencies up to the crossover point. In hat case your ears should be at the tweeters height. So i was especially excited when the folks at audiomatica asked me to beta test their latest creation, clio pocket. Dappolito polar response comparison, left a conventional arrangement using a tweeter and. Both of the woofermidrange drivers operate up to 300 hz, but one of them is rolled off at that point, with the other carrying on alone up to the midtweeter. Youll get vertical lobing if you do this, however, so itll be a sit and listen system and not necessarily as good a up and around system. D appolito designs tend to interact with the ceiling and floor alot less than the conventional tweeter over midwoofer design.
Mtm driver spacing techtalk speaker building, audio. Merch rep the community and hobby you love so much. At ise 2020 in amsterdam, the audio company will show its stingray 83. Surely there must be some good reasons for not going with such a design, such as axioms m22ti speaker. Testing loudspeakers by joseph dappolito brings essentially all the pertinent information together in one place for a nominal price. D, whose name is synonymous with the pairedvertical array widely accepted as the ideal arrangement of dynamic. The midwoofertweetermidwoofer loudspeaker configuration called mtm, for short was a design arrangement from the late 1960s that suffered from serious lobing issues that prevented its popularity until it was perfected by joseph dappolito as a way of correcting the inherent lobe. The advantage with the coaxial driver is that we get a radially symmetric dispersion without the common lobing issues you get from inter driver spacing in loudspeakers with multiple drivers. If you have been designing and building loudspeakers for more than seventeen years, then by now you would probably have rather a lot of pieces of mdf left over. It sounds smooth and sweet with a nice wide sound stage but the sweet spot is a little narrow. The dappolito design at audio video design youtube.
I think the dappolito analysis is correct and typical driver spacing. For this online publication, audioxpress kept the original article unchanged, which has. The smaller lcr6 s2 looks like a d appolito array woofertweeterwoofer, but its not one. For a given driver, bass response will extend well below that produced with. A member and fellow for contributions to the design and testing of lowfrequency loudspeakers of the audio engineering society, mr. This configuration also often known as mtm or midrange tweeter midrange extended frequency dispersion at right angles to the driver axis and minimized dispersion along the driver axis. The midwoofertweetermidwoofer loudspeaker configuration called mtm, for short was a design arrangement from the late 1960s that suffered from serious lobing issues that prevented its popularity until it was perfected by joseph d appolito as a way of correcting the inherent lobe tilting of a typical midtweeter mt configuration, at the. The final system design ive made is a soort of d appolito using the dynaudio esotec d 260 filtered passively first order at 2 khz, then the midbass range is done. Xiangsheng 728a preamp with nos tubes, pioneer elite cd player using optical out to the muse dac, into the crown xls1500 oppo83se, laptop for hires files. Some time later id gotten a set of these wonderful little drivers in my hands. I have read that the dappollito approach to speaker design is supposed. A loudspeaker configuration developed by and named for joe dappolito, in which a high frequency driver, or tweeter, is positioned between two midrange or low frequency drivers that each cover the same frequency range. A 2 way system with a tweeter beneath the low midrange driver may have a loop that is directed upward. Infinty crescendo 3008s inverted on top of infinity crescendo 3009s.
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