Time to get the speaker project going again but in a new direction. Support this channel on Patreon www.patreon.com/user?u=12254451 Email: johnaudiotech@gmail.com Thank You!
The old digs. So many memories following along the journey. And speaker projects, these are how I initially found you back in the olden days of the Tube of You. Good times. 👍
First good luck in a quick sale of your house. Second thank you very much for your Transistor Matching Video. I bread boarded your circuit. Inserted two 2N2222 Metal can NPN transistors they were close. But inserted another one perfect match. I tinker around with a lot of discrete operational amplifier circuits. So it’s really important that I have matching transistors.
The Dayton Audio DC200-8 is a lovely driver. It hits a sweet spot in TS parameters, sounds good despite having an uneven frequency response, and presents good sound detail. I used it along with a Visaton DT92 tweeter as driver replacements for an old pair of 17 liter cabinets that had Philips drivers (80652/w8 - I don't recall the number of the Phillips tweeter). Also, going off the manufacturer's response curves alone, and playing around in Xsim, I unintentionally found that what I ended up with for both Dayton Audio drivers was effectively a single pole filter, albeit for both tweeter and woofer I employed a Zobel type R-C across the driver that reduced response at the upper range of each driver. The woofer inductor is 1.8mH, tweeter filter of 10uF + 3.3R, woofer Zobel 22uF plus 4.7R, tweeter Zobel 4.7uF plus 1R. I also used a 3.3uF in the woofer LP filter, but realised this barely does anything, so could have been omitted.
higher Q mean more phase issues , that´s why big closed boxes sounds perfect for classical /orchestral music, the bass is tight and fast (with vented b. or higher Q , the low response smears a little (due to phase artifacts in the low range)) I have very similar monitors, closed big box, 8" polypropylene (an old Vifa, I don´t remember the model) with 1" aluminum tweeter (Seas H1212). I crossed them around 2500Hz, passively (If you already have the wire, you save A LOT of money on coils), the capacitors are rescued, so the whole project was not very expensive. An important issue is that, in order to not overcomplicate the crossover design, the tweeters are physically phase corrected (about 1.5-2 cm behind the front plane. Without that, you need more coils/caps in the design to compensate the phase issue. (it's super noticeable with 2nd order Butterworth filters) The cheaper way is to make a slanted box. The woofer is almost on the edge in the upper range, but being a relatively "soft" cone, it doesn't have many annoying resonances (at least at normal levels). The Seas H1212 is a marvel, lots of details, low distortion. Excellent in a "pro monitor" (I worked with several before, and the Seas tweeter has nothing to envy of similar things from Adam, Genelec or Yamaha. There are other cheap monitors - like KRK, Samson, or M Audio_ which sound much worse)
Crossing an 8" midbass over to a 28mm tweeter without a waveguide will definitely introduce a big directivity mismatch at the crossover point, which will cause a rolling listening window response in an untreated room. The DC200-8 begins beaming just under 1.3KHz and unless using a higher order filter (active with DSP would simplify this), the DC28F really needs to crossover around 1.8KHz. In the absense of a waveguided tweeter, a dedicated midrange such as the RS75 would alleviate this somewhat.
With the aluminum woofer, it's probably more preferable to go for an active, high-order crossover. If you cross it very high, the aluminum cones usually have enormous resonance peaks in the 2-4 khz range, So that this doesn't interfere, you have to cross them lower, with a high order filter (if it's a very high peak, perhaps add a notch filter) . On the other hand, a low crossover point (1200-1800) will make the tweeter howl, adding distortion in a super-critical range for listening. The balance between an 8" and 1" is a delicate thing
I've made a couple speakers and one thing I've noticed is drivers sound better in any box. Maybe with certain dimensions they sound even better still. I don't think I could hear anything like that myself. So my prediction is your speakers are going to sound good to me. Just so long as you make solid boxes that don't rattle.
"The design of active crossovers" by D. Self is some 550 pages long book about opamp based designs. But I have decided to go for dsp solution. Since I can't be asked to study acoustics, I am building a derivative of one of active speaker kits from Seas.
Sealed box looks a good choice for this driver. Going active -- presuming analog - would be very interesting to watch. Maybe you could use the JAT-501s or some of your chipamps. Rod Elliott has projects 09 and 125 to study, and of course, Linkwitz and Self. Most seem to go with MiniDSP type products which allow rapid crossover tinkering and easy tweeter delay, though these are hardly cheap, and not great if you have analog sources cause of the ADC. I can't think going passive will be more expensive than active, though, unless you are talking about an overkill filter.
Nice looking! Whenever I build a new speaker setup I always try to build the biggest box I can tolerate. Also making sure the cabinet isn’t equilateral. But I was always building large speakers using vintage altec 15” woofers and large horns ;) Your speaker setup looks good! I used to buy the expensive sonic caps, silver caps, blah blah. Now I just buy the plain ole parts express black/yellow poly caps. They work great. Add in a few air core inductors and your in business
Greetings from Serbia. It was a long time ago to remember but I think that Acoustic Research AR18 was two way sealed with 8" woofer and they used it in relatively small box so the Qtc was a little over 1. There is no need to chase 0.707. I don't think that difference in practice will be worth using bigger box. I prefer 0.3 square feet box. That's what I would build.
Yes, the crossover components get expensive. if you use Sonicaps in the tweeter crossover you'll have nearly 80% of the project cost wiped out. Speaker building is an art. Room acoustics can defeat all the effort put into the speaker and crossover. Good luck.
I like sealed enclosure sound! Ported just doesn't do it for me! Especially in car audio. Have you thought about doing both two woofers in a ported enclosure, with a sealed section to get the best of both worlds!
Great project. Have you considered the material used to construct the enclosure?BBC spent a fortune researching this for the LS35a and luckily I own a pair and I realise it’s just one factor but I think it should be considered 🤔
That is my point. How can one match speakers to the room or adapt the room for the best listening experience? For me it is irrelevant as I rarely play music because it interferes with other activities. However I am interested in the acoustic challenges.@@JohnAudioTech
Hi there, I'm working on a DIY speaker but I'm stack at a point where by i have a 200W Mono power amplifier 1943 + 5200 mono HIFI Audio amplifier finished board which requires a dual voltage ranging from +/-20v to 90v. With me on my bench i have a 24VAC single out put transformer, i searched online and i found the circuit i can use to get the dual voltage I'm looking for, after following the circuit i managed to get -36V and +36V which is a perfect range for my module, the only problem i failed to fix is the noise that goes in the speaker as they are sharing the negative terminal with the power source and the input as well. how can i solve this???
I like closed boxes too, so it'll be interesting to follow you on this build. I don't use MDF though, because of unhealthy dust when processing the material. 15mm plywood with 7+ layers will do great in this build I think? In my opinion the plywood is just as good for speaker building as MDF. Greetings from Norway.
Good luck on your sell. I'm sure it will go quickly. From what I hear everyone's still buying up the houses. Can't wait to see the video on crossovers. By the way if you ever get the QuantAslyum QA40x let me know. I made a box that will power it externally and pass the USB data lines off to the PC. Works great for mine. If you want I will make you one, orrr I can send you the parts as a kit and you can make a video about it! Take care John, see you soon!
@@cougar1861That’s a great question but I don’t know. The QA403 that I have complains about low voltage when plugged into my PC. QuantAsylum knows that some PCs can’t supply enough current to power it properly. So I created that box. Now it works great!
You need to apply more space between the tweet and woof, it is too close that makes 'the bridge' very thin and render the design out of balance (=not so nice).
I saw you struggling with your power supply limitations in your videos😂...You can buy those SMPS boards like boost converters. These boards can take 12/24V input from a battery and can give you an adjustable output at any current depending on the board you bought... They are available from 400W to 1500W and are also cheap, you can get a 1000W board for around 15-20 bucks...
First convert the volume to the units I'm using to measure. .8cu ft is 1382 cu in. Next, I figure the size I want the front of the speaker to be to fit the drivers. Now I can divide off those measurements from 1382 to give me the depth. Of course, I have to add to those measurements for thickness of the material to get the overall size of the cabinet.
You know, you should think about getting an Only fans page..... Apparently feet are a hot topic over there..... Lots of people are making a fortune from showing their feet... I'm here thinking that since you have square feet, I have never seen square feet and would seriously pay to see that! I can't measure my house in square feet because I don't have square feet.... So unfortunately for me, I have to use the French meter for that task.... Is it true that to find out your height, you have to lay down and have someone walk the length of your body? I'm still trying to figure out who and how was able to measure the height that plane's fly at.... Would have taken ages to do LoL 😂😂😂😂😂 Ah! It's so much fun picking on imperialism lol 😆.
