basshead

Explanation of the curves from the plots in the above post... "Ported" is the light green curve with near-flat response between 25-45Hz at 104db. This is with isobarik ticked in the driver tab. If I switch it back to "standard" then the curve changes to a much higher output with curve from about 104ddb at 20Hz - 110db at 45Hz. 150L encl tuned to 25Hz. "Ported (by tutorial)" with dark green curve is 80L tuned at 20Hz Red curve is one I threw in just to see what a random different driver would look like. 120L tuned at 23Hz "Existing box common enclosure" is essentially what is describes; the box minus the partition in the middle (as there are 2 drivers). I switched this to iso-barik for this go get a peak at just over 40Hz (dark blue curve). If I switch it back to standard, the curve becomes a similar shape to "existing" box but far higher level; 25Hz at 100db - 50Hz at >113db. 100L tuned at 35Hz "existing box" 50L tuned at 35Hz. Dark green curve shows peak at 60Hz. No wonder it sounds terrible. I vaguely recall using WinISD to design this box over a decade ago but possibly used factory TS parameters as I only got the DATS recently.. Finally the "sealed" grey curve is using the DATS measured data without any changes; 767L enclosure with Fsc 35Hz. I'm probably leaning towards trying out the ported (light green curve) then adding the 2nd driver inverters (for iso-barik) to see if I can get the flatter response and remove the 40-60Hz peak. Available space (pending wife approval) for a new enclosure is around 670L. That's only 100L below the Vas of one G&S driver. I've heard pre-built HT subwoofers sound much better and go much lower and louder than these two G&S 12's, and in much smaller enclosures. Hence why I'm keen to build a new enclosure for them. But if I'm going to build a box that large, I'd be very tempted to buy a couple of 18's... and then I'd need a bigger amp than the Teac... Any thoughts welcome!

I started thread here over 18 years ago and the only thing the same since that thread was created is two old 12inch G&S Designs GE7012 subs powered by a Teac Reference A-H500 (2x50W) amp. Now the HT is virtually complete (Paul Carmody Amiga towers (made by someone else), off-the-shelf in-ceiling speakers in an enclosure with baffle angled towards the rear of the room, and (DIY) Paul Carmody's Sunflower centre channel), and rear speakers (DIY) using the same Dayton Reference series drivers as the Amiga and Sunflower), it's time to build a better enclosure for these subs as they sound terrible (and seem to be much lower output in the HT space). From playing with a DATS and WinISD, it seems these subs just might need to be retired. I reconed (surround only) them perhaps a decade ago (as the surrounds had perished) and they had also been reconed by Tony Doran perhaps 25 years ago (and cones were reinforced with layers of PVA glue), so I was sceptical the TS parameters would be even close to factory specs. Hence the DATS, and the measurements I got were quite abit off the data preloaded with WinISD (assuming they're the same model drivers). For example, the DATS measured (using added mass to cone) Qes 1.1, Qms 6.636, Fs 33.55, Vas 67.1L & Qts 0.948. When I load a new project in WinISD the sealed enclosure is almost 770L with Fsc of 35Hz and Qtc 0.994! A bit of googling indicates such a high Qtc is better suited to infinite baffle. That probably isn't going to work in a 4 x 4.5m room (and with a low ceiling). After playing around with various enclosure sizes and also modelling the existing enclosure in WinISD, I seem to be getting some unusual curves. I even considered 4th order bandpass but apparently they are very inefficient and I'm not keen on buying another amp to replace the Teac. I've attached a screenshot showing the curves. I'll post more details later...

The final speakers remaining (and yet undecided) is the rear surrounds. I was initially intending to build the OS but really wanted to stick with the Dayton mids (mostly for aesthetic consistency - the ceiling-mounted atmos speakers will be concealed by grilles). The sunflower centre build is almost complete and after abit of googling I stumbled across these surround/bookshelf which also use the Dayton RS125 driver: https://www.rjbaudio.com/Microbe/microbe.html Any thoughts or opinions???

Wow I wasn’t expecting to find them at Bunnings. I searched their website and they have quite a selection. And I’m still waiting for the eBay ones I ordered over a week ago to be posted….

I like the magnets idea rather than the grille plugs/clips. I think they probably should have some material between the magnets (or magnets and metal) so the grilles aren’t impossible to remove. The magnets I found on eBay are 15mm diameter and 5mm thick and have a countersunk hole. Having the grille surface-mounted instead of recessed should make it easier to remove (without damaging it in the process).

Howdy, I’m in the process of building my first HT setup and have acquired a pair of in-ceiling speakers (thanks @BRS). I’ve built enclosures so they’re suitably angled towards the listener without protruding below the ceiling. My dilemma now is how to finish the underside. Ideally I would like surface-mount grilles, and wondered if the regular speaker grille “plugs” would be able to support the weight (being horizontal as opposed to vertical like normal floor-standing speakers). Grille size is approx 500x400mm (allowing for 50mm extra each side; the enclosures are designed to fit through the opening in the ceiling, hence the large grille size). Another idea was magnets so they attract to the metal furring channel, but again I don’t know if any magnets would be strong enough to hold the weight (also though 10mm gyprock). Another idea is to flush-mount by using pvc edge moulding (like this https://www.blacktownbuildingsupplies.com.au/product/pvc-end-cap-mould-4-5mm-x-3-0m/) to “frame” the opening, and use small right angle brackets affixed to the inside edges of the enclosures to secure the grille to (eg. using the speaker grille “plugs”) Here’s an in-progress photo of one of the enclosures… I actually built one out of gyprock first, but the plywood one was much lighter (and obviously stronger, and quicker to build). Enclosure size was limited by the spacing between the furring channel but I could’ve made them a little wider to prevent the direct sound wave from the mid cone being partially blocked by the front (back?) of the enclosure. I’ve got some scrap white semi-sheer fabric I’ll try out as the grille cloth.

Just saw this thread after posting in another thread about atmos speakers… Interested!

So the “2nd living room/study” (aka HT) build is progressing slowly and I’ve been researching receivers and was initially thinking of Yamaha RX-V4A until I read you can’t switch between 5.1 and zone2 (2ch in another room) - it’s “set and forget” - either 3.1 in main room and 2ch in another room, or 5.1 in main room and no 2nd room. Then I looked at the V6A which seems to offer much more versatile options and will allow a zone 2 simultaneously with 7 channels for the HT (incl. either 2 atmos or 2 rear surround channels)… Which leads me to the question of whether the OS would be suitable as atmos height speakers. I’ll already be making a pair for the rear to match the Amiga front mains. Mounting them either on the wall (as “high” bookshelf speakers) or perhaps with some modification of design (thinking angles) for mounting on (or perhaps somehow recessed in the ceiling)? Thoughts and opinions welcome!

My long-term passion for Amiga is what drew me to these speakers in the first place!

Back to my old CAA/SNA stomping ground after a long hiatus (and a password reset)… I’m considering building a pair of Amiga’s too after finding Paul Carmody’s page and PE techtalk forum where I also bumped into @Geoff Millar who has been rather helpful. Your cabinets look great!

I got the plate amp from Altronics... It wasn't a direct drop-in replacement as the original cut-out wasn't large enough and was too difficult to remove the bracing inside the box, so I built an external box just for the new amp and ran speaker wires through the box port. Sounds good as new!

Blast from the past (both me, and this series of 5.1 speakers)... Long story short, I need to replace the built-in plate amp for a dual-8inch powered subwoofer from A 5.1 speaker set I bought second-hand last year. It is known for crackling and popping sounds after a few years old, and my local electronics repair shop quoted more than the cost of a whole new unit to replacement the plate amp with genuine from CV. With the help of my brother, we did some repairs on it and it worked for awhile, but the intermittent noise returned after a few months. Having reading up on various forums it could even be the glue and PCB causing issues with high humidity (although the split a/c fires directly onto it from the other side of the room). I have found some potential candidates for replacement plate amps but wanted some "expert" opinions (having little to no response from other forums). The existing amp rating is 125WRMS/150WPeak. The Dayton Audio SPA250 would be over-powering the subs by around double, but shouldn't be an issue. I haven't confirmed if the existing 125WRMS is @8ohms or 4ohms, and I can't remember if the two drivers are in series or parallel, nor what their ohmage is; I could pull it apart again and find out). Altronics have a 180W plate amp https://www.altronics.com.au/p/a2451-opus-one-180w-active-subwoofer-amplifier/ for less than half the price of the SPA250. I thought Jaycar used to sell plate amp kits (decades ago?) but I can't seem to be able to find any. If I get the Dayton I'll be tempted to build another duplicate box and power both from the one amp

No longer 4sale as I have used it to run an outdoor entertaining area stereo system.

I have used the 300uF capacitors in series with the coaxials and it doesn't sound like there is much gap. I may need to now build an L-pad to reduce the output of the coaxials (even though they have a lower sensitivity than the subs, and I prefer more bass than less ). Either that or play with the loading/direction of the subs to achieve a perceived higher output.

The single 9mH inductor in series with the sub works... Now to wire up the midrange/coaxials in series with the 300uF capacitor... If I find there's too much gap I could also use a larger capacitor (about 500uF for 80Hz low-pass according to your link). Would it be bad (too low ohm load for the amplifier) to not use a capacitor at all, and run the coaxials directly off the amplifier (while still having the subs connected through the inductor)? I don't know if this would have any affect on the load to the amplifier, but I wont be listening at high volumes (I don't want the neighbours to complain!). If you know the amplifier, I haven't turned it up past "-33" with only the coaxials connected (while "-37" is a reasonable listening level, I probably wouldn't want to turn it up much loader than that). Remember all the speakers are 4ohm and while I didn't mention it before, the amplifier prefers an 8ohm load (rated at 2 x 50WRMS @ 8ohms). Would it damage the amplifier to just have the bass frequncies at a lower (2ohm) load while only at low output volume?

Both the coaxials and subs are both 4ohms. The subs are single voice coil. From memory (I can't find my original notes in my overflowing folder), the crossovers were originally designed roughly to be low-passed at about 80Hz, so the 71Hz you've stated is probbaly more accurate. The boxes I've just built for the coaxials are ported and tuned to about 80Hz (in case I wasn't able to incorporate the subs into the system). I'm not overly worried if they end up being high-passed at 113Hz. The link you provided shows I currently have a 2nd-order low-pass filter. It appears I could re-use my crossover components and rebuild a two-way 1st order crossover: 300uF cap in series to HP @ 130Hz for the midrange/coaxials and 9mH inductor in series to LP @ 70Hz. There would be a gap but I don't think it would be a problem (or would it? - it's almost a whole octave).

I've almost finished installing some outdoor entertaining area speakers... I'm on a budget, so the midrange speakers are a fairly cheap set of 6inch car coaxials, and amplifier is the Teac Reference amp I had/have advertised in the 4sale section (I know it's a waste to use it on such low quality speakers, but it's not being used and it saves me buying more gear). What I want to do is try and modify my passive crossover which I built for a pair of 12inch subs so that I can incorporate the subs into the outdoor system, running from the same 2ch amplifier as the coaxials (the same Teac amp I was originally using for just the subs, when they were in my lounge room years ago). The existing crossover which I made for the subs consists of a 9mH inductor in series with the sub voice coil and a 300uF capacitor in parallel with the sub voice coil, multiplied by two (one set for each sub, which are 4ohms). Let me know if I'm way off track here... I'm exhausted, dehydrated and sunburnt and my brain isn't working very well, plus it's been several years since I've looked at any of my notes... I can think of two options (keeping in mind the previous paragraph!) - first is to just run the coaxials in series with the sub (I have a feeling this will cause the coaxials to be low-passed). Second thought is that I need to modify the crossover somehow to make it a two-way crossover (one high-pass output for the coaxials and one low-pass for the subs). I've googled and found many webpages on crossover designs, but like I said, my brain hurts. I came across this page: http://www.trueaudio.com/st_xov_1.htm and it looks like I already have a two-way crossover - so would I just connect the coaxials in series with (after) the capacitor in my existing crossover? Is that now three options? To confuse myself even more, the bit of paper in front of me dated October 2001 (which would be after the time I built the crossover) has a schematic of incorporating switches to bring a 5.6mH inductor and 150uF capacitor into the crossover, but I can't remember what I wanted to do that for (I'm guessing to change the crossover frequency?). I think I got all my component values from the back of an old DSE catalogue (in the specifications/technical data section). Let me know if there's any more details you need to know; it wouldn't surprise me if I've left something out!

I don't know if I've used the correct cable, but it seems to be working well so far (even with the cable near two computers with their case sides removed). I made sure I ran the cables away from power cables under the floor. I have run 10m of 3-core (shielded) PROLINK brand interconnect cable (about $4.50/m from Jaycar) and soldered the ends to RCA jacks mounted on standard size wall-plates. I used 3-core as I have left, right, and a video signal cable as well.

Another update... We've moved house (4 months ago) and now I've reached the stage where I need to get a whole lot of audio from cassettes onto the PC hard drive so I can put it onto Clare's iPod. Now that the Sony double-cassette deck is already installed into the TV cabinet (and it would be such a pain to remove it and put it next to the PC in the adjoining room), I'm going to need to run some cables from the cassette deck to the PC - about 8-9m if I go through the doorways, and probably about the same if I go under the floor. Unfortunately all my RCA leads joined together (I have 4 straight-through connectors) is still too short to reach, so I'll have to make up some leads, and may as well run them under the floor and through the existing holes in the wall I made behind the TV cabinet and PC. Is it ok to run RCA level signal that distance (keeping in mind the previously-mentioned problem with the video camera). I reckon there shouldn't be a problem if you can buy leads pre-made that length to begin with... I don't want to go to the trouble of balanced leads as I have no additional connections to terminate at either end (assuming balanced leads need extra connections - eg - ground/shield). Do I just use any old 2-pair shielded cable and put connectors on the ends? Obviously to make it neat I would use wall-plates with RCA jacks on them, and then use short leads from the wall-plates to the PC & cassette deck.

All details can be found http://www.teac.com/consumer_electronics/r.../ref/A-H500.htm on Teac's website (there is a photo of it there, too). (copied below) A-H500 Integrated Amplifier Main Features 50W + 50WRMS 8 Ohms Left-right separate circuitry Toroidal power transformer 4Ohm Speaker drive capability Motor-driven volume control Tone control (bass, treble) CD Direct 6-Input selector: Tuner, Tape 1, Tape2/MD, CD, Phono, Aux Record selector: (Tape 1-2, Tape 2-1, Off, Source) Headphone jack Unswitched AC outlet x 2 Binding post speaker terminals System Remote Control Include Specifications Power Output: 50W + 50W RMS (8 Ohms) 80W + 80W RMS (4 Ohms) Total Harmonic Distortion: <0.03% (1kHz, 8 Ohms 45W) Signal-to-Noise (IFH-A): Phono: 67dB Aux, CD, Tape, Tuner: 95dB CD Direct: 100dB Input Sensitivity/ Impedance: Phono: 2.8mV/10k Aux, CD, Tape, Tuner: 180mV/10k Frequency Response: 5Hz-80kHz Tone Control: Bass: +/- 10dB (100Hz) Treble: +/- 10dB (10kHz) Power Consumption: 360W Dimensions WxHxD (USA): 285x131x329mm (11½" x 5¼" x 13 1/8") 6.9kg (15 lbs) REASON FOR SALE: Moving house (and hopefully getting a new stereo system). I'm also not allowed to keep the the existing boxed G&S Designs GE-7012 for the new house's lounge room, so there's no point in keeping the amplifier I used to run them! Originally purchased from Marc Rushton many years ago (so he can vouch for it, I'm sure!) COST: All offers considered. I don't know how much a new one costs (or even if they're normally available in Australia), and I can't remember how much I bought it off Marc for, either! CONDITION: Excellent. I would like to sell it ASAP (within 3-4 weeks, so it doesn't have to be packed away for the moving-house). Delivery available in Sydney (if you're not an hour away!). Will post/courier if required. Direct Deposit into my account is preferred, otherwise Aust post COD/money order. Auditions? The subs I was running off it are no longer connected, and the speakers I have remaining in the lounge room would most likely suffer immediate melt-down if they were connected to it

Time for a brief update: I have decided (read: been allowed) to get a separate amplifier/tuner and use the existing speakers. I still wont be purchasing until after we buy & move into the new house, but I've been looking at some cheaper alternatives than the Harman Kardon unit I first looked at. It looks like I'll be leaning more towards more hip-pocket friendly (and mainstream) brands such as Pioneer, Panasonic, Sony, etc. as they seem to do just as good a job (for what I'm after) for between 1/3 and 1/2 the cost of the Harman Kardon unit. A couple of weeks ago my local NAPF store had a special on Pioneer VSXD514 marked down to $349 from $469 (Am I allowed to quote store names and prices here? They're probably all sold now at those prices anyway!). This unit seems to do all I'd ever need, or I could get the next model up (VSXD714) which has additional (A+ speaker outputs which I could use to run speakers in another room (eg: upstairs?)... I'll then decide if the speakers I have aren't up to the task, after I've connected it all up. I reckon the easiest thing to do as has already been mentioned, is to go wireless for audio signal...

I'm expecting to buy a house in the next month (I hope!) and I wanted to find out how to go about wiring it up so I can play MP3's (as an example) from the PC in one room, through the main stereo in the lounge room. One suggestion made to me (from CAA) was to use wireless to get the signal from PC to lounge room stereo system, which I think would be the simplest and relatively cheap way to do it. Ask me anything to do with electrical cabling, or fiber-optic cabling (well splicing, at least), but when it comes to which types of cables I need to use for low-level signal, I have no idea: I am 100% sure a standard RCA cable wont do the trick as it would be too far a distance (I've proved that by trying to use a video camera to display a concert stage on an overhead projector/screen). Feel free to correct me if I'm wrong! I have come across this in my searches: http://bwcecom.belden.com/College/Techpprs...rs/rhtheatp.htm If I'm better off not using signal cable of some sort, and just using the wireless tranmitter, tell me now I'd also like the ability to send the signal from a cassette player (in the lounge room) to the PC (ie: reverse direction to previous example) as one day I'll get around to copying the rest of my old cassettes onto the hard drive to convert to MP3's... As for signal cables, I've done a similar set-up in my unit where I used a CAT-5 cable to play DVD's (from the DVD-ROM in the PC) through the stereo & TV on the other side of the lounge room. While this worked, it wasn't very good at all (noisy signal on both the video and audio, for only a 7m length of cable under the floor). It might be worth me mentioning that I am also going to replace the existing 10-year-old "Dolby Pro Logic" lounge-room stereo with a more up-to-date 5.1 (or similar) unit. While I don't watch too many DVD's, I'd like to enjoy listening to (or is the correct term "experiencing"?) them. The problem I have here is that I want to retain the usage of my two old 12inch G&S Designs GE7012 subs powered by a Teac Reference 2x50W amp. I have considered two options: 1> buying a whole new system & speaker for the lounge room, and use the existing lounge room stereo & it's speakers for the PC (which currently has no speakers - only headphones), 2> Keep the existing lounge room speakers but use them with a new control unit, and buy some cheapo speakers for the PC. If it turned out the existing lounge room speakers are crappy (which they may well be, considering it's a 10-year-old all-in-one stereo package), then I could replace them at a later date when funds allow. If I went with option 1, I'd probably be better off ditching the G&S subs and amp and buy another all-in-one package complete with sub. I hope my descriptions above haven't made it too confusing to imagine what I'm trying to achieve I'd thought I'd post my thoughts here before I get taken for a ride at my local HiFi shop. So far all I've done is popped into HomeZone in the city and picked up a Harman Kardon brochure. I was recommended a just-below-$1000 tuner/amplifier there, which is probably a significant chunk (if not all) of my budget... edit # 3(?) - I've had a look at the back of my cheapo DVD player and it's only got RCA L & R audio outputs - NO digital (after the salesperson @ Homezone insisted that ALL DVD players have optical audio output!). For video it has S-VIDEO, plus composite (three separate RCA's?) and (two channels?) of standard VIDEO RCA output. Maybe I would be better off buying a new all-in-one stereo package as 99% of them all come with a DVD player built-in (and I'd assume the internal connections would be better than the analogue RCA connections I already have).