Ty Salas, I will build that box to start with and then try some solutions for the filter. I have noticed that the woofer has an increasing impedance from 1kHz and upwards, but in your measuring this is gone so I wonder how it is done.
My initial thought was to use a low crossover frequency, something like 2kHz to be sure not to push the woofer too much, and since the tweeter got a Fs of 700Hz (I saw somebody measuring this finding it was a little higher around 800Hz) I think it can handle 2kHz just fine, but I probably need to try it before I can say if it works. I am excited with this since it is my first speaker project. Any input is welcome!
My initial thought was to use a low crossover frequency, something like 2kHz to be sure not to push the woofer too much, and since the tweeter got a Fs of 700Hz (I saw somebody measuring this finding it was a little higher around 800Hz) I think it can handle 2kHz just fine, but I probably need to try it before I can say if it works. I am excited with this since it is my first speaker project. Any input is welcome!
Last edited:
The Iron Lawbreaker satisfied the goals at hand for a 2 way - I extend the basic approach to 2 1/2 way configurations for larger speakers.
For this speaker, in a volume of approx. 3.5 cu ft, I wanted the maximum broadband efficiency, good quality bass with good extension, a flat response and low distortion at high levels, and I think I achieved it, with a response down to 50-60hz flat @ ~99db/w/m. The HF driver is an Altec 288G and the bass driver is a JBL 2220A. As a side benefit, I was able to achieve a very flat impedance of between 16 - 20 ohms between 40 and 240 hz due to adding ~ 1 cu ft of activated charcoal to the enclosure (in gas tight bags) to increase acoustic compliance and using a special xover/frequency shaping circuit in the bass featuring a custom air core transformer that allows minimum component count bass response shaping with the loss of almost no efficiency or damping and also serves as a series inductance to the woofer - the only series woofer xover component (although I also use 600uf of bass polypropylene AC coupling to reduce cone movement from out of band LF). With an overdamped tuning of the box to ~32 hz, the overall bass quality is surprisingly tight and very detailed - more like that of a closed box than a conventional ported system, only in some ways better yet since the impedance is so constant throughout the bass passband (no Zobel networks used). There is some serendipity with this all coming together as well as it did, IMO. With this design, using Elliptical xover filters allowed me to reasonaby approximate a first order xover response with the minimum possible driver overlap & allowed an xover ~550hz which minimizes Doppler distortion.
I like these a lot! Since I can't hear much over 8kHz, I would go with the B&C DCM50, a nice JBL 500Hz horn, and a 15" B&C woofer, active crossover @ 500Hz of course.
B&C SPEAKERS
There is an RLC conjugate that helps the impedance. Just make the crossover as recommended since it has been tried lower also etc. to have a reference. Its mature as it is. Then you may try whatever. Good luck.
Don't forget to recess the tweeter in the baffle at least. But try the woofer too to keep the emitting points alignment as in the original. It may be 2-2.2kHz cross or something already, as you have seen my notes weren't precise anyway. Has good mid projection no worries, I listened to it recently again.
I think 99dB 1Wmtr down to 50Hz is overrated in that compact design. I think 96dB 1Wmtr is more realistic.
Monitor-xl does 92dB 1Wmtr and has response down to 30Hz that is high efficiency to to have cut off that low at 92dB 1wmtr.
Yes Salas, I will do that to both drivers, getting the tool for it. You said it was made from 19mm, I was thinking of maybe doing it with 22mm cabinet keeping the same internal measures for stability. I know this will make the cabinet a little wider (6mm), do you think it is a good idea or will it change the sound?
I will use all film capacitors and good quality coils. That big one of 2.5mH, what do you suggest for it? I want something good but not costing a fortune (less than 40 Euro).
I will use all film capacitors and good quality coils. That big one of 2.5mH, what do you suggest for it? I want something good but not costing a fortune (less than 40 Euro).
A 2mm wire air coil was used for the 2.5mH. See the DCR of such in vendors lists and match it for other types maybe cored high power you may opt for, cost wise. Yes you can use thicker material 22mm and keep the internal proportions the same. The difference in external size will be negligible for altering diffraction due to dimensions drastically.
Yeah, maybe so. The B&C 15PS100 is pretty good. The -3dB point is about 45Hz, sensitivity is about 94dB, in a 2.5 cu ft vented box tuned to 42Hz. Group delay peaks about 12ms just below the -3dB point. With 300watts in, I see about 115dB at the -3dB point. The tweeter would have to be padded down heavily of course.
Attachments
When do you start.
I like B&C but, I have a better tip then the B&C the beyma sm115N 97-98dB. Can not find a better one for the money.
For your application also the beyma 12BR100 94dB is a sharp priced studio driver. Also good for high efficient hifi use. To keep it affordable look at the 18sound horn + driver xd125 XD125 - HF Compression Driver
Also would match nice with the 1,4" fatial pro driver and horn down to 500Hz. Has also a nice price tag.
An externally hosted image should be here but it was not working when we last tested it.
FaitalPRO - Professional Loudspeakers Made in Italy
FaitalPRO - Professional Loudspeakers Made in Italy
12br100
http://profesional.beyma.com/pdf/12B100-RE.pdf
sm115
http://profesional.beyma.com/pdf/SM-115%20NE.pdf
attached simulation 12br100 94dB 1wmtr tuned to 40Hz 90liter.3,2cu/ft -3dB 35Hz. group delay 17msec on tuning frequency. Higher delay does mean more resonant.
The 12br100 and the 180 sound horn plus driver will cost you some where between 250 and 350dollar for a set. So you can build a hornloaded studio monitor -3dB 35Hz-18kHz 94dB 1Wmtr under 1000dollar.
first picture driver response second basreflex port response last groupdelay.
Attachments
Last edited:
additional data on the 12br100 from "Klang und Ton" a recommended diy loudspeaker magazine. Very good controlled THD with low third harmonic even at 100dB.
price
Beyma Speakers - Beyma 12B100R speaker - Beyma 12B100R 300 watt 12" woofer for all hi-fi and studio monitor bass speakers. Beyma 12B100R and other Beyma 12" speakers here.
xd125 padded down I would dare to cross it at 1,5kHz with the beyma 12br100 when you want to go save third order.
Horn Tweeter Eighteen 18Sound XD125 1" With Driver
Like I already thought total under 300dollar great stuff bottomprice.
Strange the fatialpro HF144 is even cheaper as the HF140 it is here the more expensive and better one.Faital Pro HF144 - Faital Pro HF144 1.4" neodymium high frequency compression driver with a ketone polymer diaphragm. Faital Pro HF144 HF drivers available here at US Speaker.
price
Beyma Speakers - Beyma 12B100R speaker - Beyma 12B100R 300 watt 12" woofer for all hi-fi and studio monitor bass speakers. Beyma 12B100R and other Beyma 12" speakers here.
xd125 padded down I would dare to cross it at 1,5kHz with the beyma 12br100 when you want to go save third order.
Horn Tweeter Eighteen 18Sound XD125 1" With Driver
Like I already thought total under 300dollar great stuff bottomprice.
Strange the fatialpro HF144 is even cheaper as the HF140 it is here the more expensive and better one.Faital Pro HF144 - Faital Pro HF144 1.4" neodymium high frequency compression driver with a ketone polymer diaphragm. Faital Pro HF144 HF drivers available here at US Speaker.
Attachments
Last edited:
I had a day off today and a lot of energy leftThanks Helmuth! Give me some time to digest all of this information you presented. I do have to work!!!
Inductor.
I am thinking of replaceing the 2.5mH 2mm air core inductor for a 2.5mH 1.2mm idnuctor with non ferrite core JANTZEN-2005 - Jantzen Wire non-ferrite cored coil 2,500mH 0,268Ohm 1,20mm - Europe Audio
Will this work good? I think the air core one is a bit expensive and have heard some good things about this type of inductor and they are cheaper.
I am thinking of replaceing the 2.5mH 2mm air core inductor for a 2.5mH 1.2mm idnuctor with non ferrite core JANTZEN-2005 - Jantzen Wire non-ferrite cored coil 2,500mH 0,268Ohm 1,20mm - Europe Audio
Will this work good? I think the air core one is a bit expensive and have heard some good things about this type of inductor and they are cheaper.
Love my HDS...Pic attched.
Morel tweters are great, the Vifa supplied with the HDS will give them a run for their money.
Morel tweters are great, the Vifa supplied with the HDS will give them a run for their money.
Attachments
Crossover placement?
It is not going very fast, but I am expecting my crossover parts soon and will build the cabinet for Salas 2-way speaker. Where do I place the crossover in the box? Does it matter? I am considering either at the bottom or the back panel close to terminals. Or is it even better to have it outside the box to keep it cool?
It is not going very fast, but I am expecting my crossover parts soon and will build the cabinet for Salas 2-way speaker. Where do I place the crossover in the box? Does it matter? I am considering either at the bottom or the back panel close to terminals. Or is it even better to have it outside the box to keep it cool?
Yes, Salas assisted Mikvous it should read, sorry about that. I will use the crossover outside the cabinet at first, checking I have done everything right and also the drivers may sound different after some playing. I read somewhere it is good to keep the crossover cool to avoid it changing, but I do not know how critical it is, probably it will be ok inside the box since that is the usual way to place it.
- Status
- This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.