So as I promised I would give you the details of my DIY in wall system in our new home.\n\nI might as well come clean now. I have a period of enforced idleness. I had a prostate biopsy on Monday at Mayo. Since I'm an old bloke passed my cell by date, prostate cancers are part of the turf. I should have the results in the next few days. So I await to see the grade. The probability of cancer being present is high. However a lot of superannuated guys like me die with prostate cancer, but not from prostate cancer. Anyhow what is will be.\n\nSo since I have ordred idleness for a couple of weeks, it is a good time to post details of the three system here.\n\nFor background here is a link to the build thread.\n\nWe have to be mindful of aesthetics. An ugly cobbled system is not pleasing however good it sounds. Making a system pleasing to the eye has to be part of a project.\n\nMy wife liked our system in our Eagn town home but hated the look of it. I don't blame her.\n\n\n\nThat was not an elegant system. However we knew our ownership if that property would be relatively short. It turned out to be 11 years. So we did not want to make major structural alterations.\n\nIn our new home, I had not considered putting a major system in the main living area of the lower great room. However my wife wanted one. She did not want any "boxes" in the room and it had to be as unotrusive as possible. She wanted it to sound at least as good as the system she was used to.\n\nShe had no idea what a tough challenge this would be. It seemed to me an in wall system would be mandatory.\n\nNow this is a huge space.\n\nLiving room.\n\n\n\nIt is contiguous with the kitchen, dinning room, stairs to the upper level and the entry way and a passage way to laundary and other areas.\n\n\n\n\n\n\n\nSo you can see that is a big space to fill. Since the space is so open, I thought a 3.1 system would be optimal. Actually a 2.1 could probably fit the bill, but I wanted to design a three way center.\n\nSo I thought I would build the system in wall by building out the fireplace breast.\n\nObvioulsy the speaker system needed to handle significant power and significant power provided.\n\nThe elctronics would be a 65" Panasonic plasma from the Benedict AV room, a Marantz 7701 from the Eagan townhome, an Intel NUC, a Panasonic BD player, Comcast TV unit connected to the one in the studio which is the master, an APC Smart UPS, and two Quad 909 power amps providing 1000 watts of power all channels driven.\n\nSo my biggest concern was getting adequate uniform bass coverage, given the space avialable. There would only be room for one sub. However experience has tought me that TL speakers are highly efficiant and can can uniformly cover a large area due to the encircling nature of pipes. So an in wall TL sub was designed and built to carry out this task. You can see the deatials of the build in the build thread.\n\nFor the left and right mains and center high powered drivers were required. For many reaons, space and integration I thought selaed spekaers would be best for the task. I wanted and F3 of around 80 Hz to make for easy integration with the sub. This did not quite work as planned due to the in wall location. I knew not to provide baffle step compenstion as being in wall there is no half space\/full space transition. However I thought the gain from the flat wall would be hard to calculate and so it proved\nThe feeds for FM TV and Internet come down from the studio chase in Tech Tubes. Tech Tunes also link the ancillaries, pre\/pro and power amps.\n\nSo I chose for the bass mids six Morel 6" 638 Bass mids were selected for the three speakers. Each bass\/mid is in its own enclosure. This is best practice for sealed designs to prevent drivers from driving each other. They are therfore acoustically isolated. For the right and left speakers Scanspeak 1" soft dome D2608-913000 were selected.\n \nFor the mid range of the center this small but potent Morel EM 428 was selected. It is in its space with the tweeter.\n\nThe tweeter for the center selected was a 3\/4" softdome Eton 19 SD-1. This tweeter is pretty much an exact copy of the old Dynaudio D 21 AF. Sadly the Eton tweeter is discontinued. However I'm pretty sure I can adapt the design for the Hiquaphon 3\/4" dome if anyone wants to build this system.\n\nThe sub driver is the: -\nDayton Audio RSS265HO-4 10" Reference HO Subwoofer 4 Ohm\n\nThis is the model for theTL Sub.\n\n\n\nI have linked the box and crossover models.\n\nSo how did it turn out? There were some issues. The wall reinforcement of the bass mids necessitated the crossover from the speakers to sub be 40 Hz and not 80Hz. Even so there is still reinforcement around the sub crossover, causing slight coloration, and I mean slight on voices, and makes the system slightly warm, which is not unattractive.\n\nSo here is the impedance curve of the right and left mains.\n\n\n\nSo you can see the speakers are 4 ohm. There is one peak of impedance for the sealed alignment, and a peak just above the crossover point of 2.5 KHz. The phase angles are benign. The low pass crossover is first order and the high pass second order. However this makes for a composite fourth order crossover when driver roll offs are added.\n\nThis is the on axis FR at 2 meters.\n\n\n\nThat is a very satisfactory FR and impulse response.\n\nNow the horizontal off axis responses. 15, 30, 45 and 60 degrees.\n\n\n\nThe green trace is 60 degrees. That is excellent dispersion.\n\nThe center impedance curve.\n\n\n\nAgian there is one tuning peak. There are some swings of the phase angle, but the negative swings are where impedance is high. The impedance does drop to 3.5 oms at the 400 Hz crossover point. Electically the crossover are second order at 400 and 4000 HZ. So the entire speech discrimination band is handled by the midrange driver, which really aids voice clarity.\nThese are the dispersion characteristics. However there is little change in voice clarity whether just the right and left speakers are used or the center as well. Speech is marginally clearer with a 3.1 source.\n\nThe center speaker FR\n\n\n\nNow this shows the biggest issue. The black trace is the axis response and the FR improves as you move off axis. This dip is due to an out of phase condition between the mid and woofers at crossover. However reversing the polarity of the mid causes a bigger problem in that it then puts the midrange out of phase with the left and right bass\/mids over a large frequency region and was not pleasant at all. Fortunately the problem resolves off axis and the total system resonse is satisfactory and this is not a severe problem.\n\nNow to the sub.\n\nHere is the impedance curve.\n\n\n\nYou can see one peak of impedance showing that the line is correctly damped. You can see that the pipe is supporting the driver into the 15 to 20 Hz range. The driver is not fully decoupling from the line until 15 Hz.\n\nThis is the FR of the sub.\n\n\n\nYou can see that maximum output is at fp just below 40 Hz. You can see the pipe is supporting the driver over a full two octaves from 20 to 80 Hz. So the TL is working as it should and giving much broader support to the driver than a conventionally ported sub.\n\nHere are the far field FRs of the system. I measured all off the listening positions, and also took one over in the dining room and one at the kitchen cook top where the left speaker is not even visible. This latter is the green trace.\n\n\n\nAs you move away from the speakers, there is a fall off in the higher end as there should be. If this is corrected the sound is not natural.\n\nThere is a rise at the sub\/speaker crossover at 40 Hz, which gives slight warmth to the system. The sub is so effient Audyssey puts it 12 db down compared to the other speakers.\n\nSo how does it sound. Very good. So in a TL one 10" driver does fill the space. This is a huge space open to the house, and the bass is plentiful and unclored. Organs are reproduced with great authority. So you don't need large numbers of subs, huge drivers and insane amounts of power to fill a very large space, open to a large stairway.\n\nI have caught my wife cranking the system very loud, without distress. She by the way is thrilled with this system of which she has taken over total ownership.\n\nVoice clarity and speech intelligibility is excellent. In fact you can here dialog easily on the upper landing wihtout the system playing loud. It just sounds like someone talking downstairs.\n\nI can listen to any music or program I want on this rig without complaint. So I have to report the system a succesful design.\n\nIf anyone wants to build it, then I have all the speakers in computers at the cabinet shop in Albany MN. So we could crank out a flat pack in literally minutes for anyone interested.\n\nThe speakers are all 4 ohm, and the center has a drop below 4 ohms where there is significant power. The Quad 909s though have run cool, and never triggered the fans to come on which are under thermostatic contriol. The power amp case has never got over 3 C above ambient temperture. However Quad current dumpers run cool, which is just one of the reasons I favor them.\n\nWhether a receiver would tolerate this speaker system I do not know. If not pushed hard I suspect it would. Decent power amps however would be the safer choice.\n\nI will report on the other two systems in further threads. Also I did a system for the owners of our former lake home using Elac speakers and I did get a few measuements. Stay tuned.