Hi' Everybody. I hope you all are having a great day.
I think my search for full range speakers have come to an end when I purchase my friend's "Philips AD1255/M7" speaker pair. Previously I bought a pair of Philips AD80800 and ended up with disappointment. However, I wanted to buy something that sounds closer to the AD1255/M7 because he gave them to me just to listen to them. I ended up buying them,
They came in a home built enclosures which seems pretty old and not in very good shape. I am thinking of either building a new enclosure or getting them back in good shape for the time being.
Any recommendations for an enclosure build that suits a 12 inch Philips full range speakers...? I'll be glad to look into them, get them built.
Tomorrow i will try to post some photos of the enclosures I currently have so I can get an Idea from you.
The current enclosures look a little like the one in the photo Which I have attached.
The large boxes have two extra drivers "Highs and Mids" with a crossover inside, They were in bad shape so i disabled the crossover and put a direct wire. Box doesn't have a bass port as well.
I don't know much about speaker enclosure building, but I do have a person who can do modifications or build them, Should I add a bass port to the bottom? Will it improve the sound or having a sealed box is better for them?
I think my search for full range speakers have come to an end when I purchase my friend's "Philips AD1255/M7" speaker pair. Previously I bought a pair of Philips AD80800 and ended up with disappointment. However, I wanted to buy something that sounds closer to the AD1255/M7 because he gave them to me just to listen to them. I ended up buying them,
They came in a home built enclosures which seems pretty old and not in very good shape. I am thinking of either building a new enclosure or getting them back in good shape for the time being.
Any recommendations for an enclosure build that suits a 12 inch Philips full range speakers...? I'll be glad to look into them, get them built.
Tomorrow i will try to post some photos of the enclosures I currently have so I can get an Idea from you.
The current enclosures look a little like the one in the photo Which I have attached.
The large boxes have two extra drivers "Highs and Mids" with a crossover inside, They were in bad shape so i disabled the crossover and put a direct wire. Box doesn't have a bass port as well.
I don't know much about speaker enclosure building, but I do have a person who can do modifications or build them, Should I add a bass port to the bottom? Will it improve the sound or having a sealed box is better for them?
Attachments
With this old drivers, you really need to measure them to know the specs. Even the original spec list won't be right as they change by aging. With something like a Dayton DATS (about 150€) that is very easy to do.
I've seen this in a 150L sealed on a forum. But not more info about it.
I had this document where on page 55-56 they speak about a minimum size of cabinet for this one (in metric sizes as Philips is Dutch)...
Dropbox - Philips_ApplicationBook_BuildingHiFiSpeakerSystems_1970-10.pdf - Simplify your life
But these drivers were made before (1969-1971) the T/S parameters existed so there are not really specs we can use with modern techniques that are known.
I've seen this in a 150L sealed on a forum. But not more info about it.
I had this document where on page 55-56 they speak about a minimum size of cabinet for this one (in metric sizes as Philips is Dutch)...
Dropbox - Philips_ApplicationBook_BuildingHiFiSpeakerSystems_1970-10.pdf - Simplify your life
But these drivers were made before (1969-1971) the T/S parameters existed so there are not really specs we can use with modern techniques that are known.
I think the enclosures that i already have has a very similar design. Just needed some touchups and they are good to go.
Please take a look.
They have idle holes behind the mesh which belonged to a tweeter and a mid range which i think needs to be sealed off.
Please take a look.
They have idle holes behind the mesh which belonged to a tweeter and a mid range which i think needs to be sealed off.
Attachments
Old Philips book in public domain http://www.introni.it/pdf/Hull (Philips) - Building HiFi Speaker Systems.pdf
Enjoy [DIY] Four simple DIY loudspeakers
Edit: Video test Philips AD 1255/M7 fullrange. - YouTube
Enjoy [DIY] Four simple DIY loudspeakersEdit: Video test Philips AD 1255/M7 fullrange. - YouTube
Here are the parameters I measured from my pair years ago:
Re=4.72 ohms
Fs= 43.07 Hz
Qts=0.533
Qes=0.571
Qms=7.975
Le=0.154
Mms= 32.96 grams
Vas = 183.1 Liters
Re=4.72 ohms
Fs= 43.07 Hz
Qts=0.533
Qes=0.571
Qms=7.975
Le=0.154
Mms= 32.96 grams
Vas = 183.1 Liters
Well, with the data provided above i come to a 500L cabinet with a slot port of 10x26cm of 18mm deep (if using 18mm wood). This gives an F3 of 30 hz. Smaller gives a big bass boost. 150L with a port of 7x15cm and 18mm deep gives a F3 of 43.5Hz but with a boost at 75hz of 2.7dB.
I don't know how much the xmax is, but at 98dB/2.83V/1m efficiency with those specs, i guess 2w/8R gives you more than loud enough (+102dB with a pair) for an average living room so not so much xmax is needed i think...
That is off course, when the data provided is right. But winisd checks the consistance of it and it passed the test (wich is rare with provided specs).
I don't know how much the xmax is, but at 98dB/2.83V/1m efficiency with those specs, i guess 2w/8R gives you more than loud enough (+102dB with a pair) for an average living room so not so much xmax is needed i think...
That is off course, when the data provided is right. But winisd checks the consistance of it and it passed the test (wich is rare with provided specs).
They have underhung coils. > 1 mm excursion either way and the coil will start to leave the gap.
Thanks!
Yikes! ~280.65 L/0.707 Qtc/55.36 Hz Fc
50 L = ~1.0875 Qtc, ~93 Hz Fc, so back in the bad old days of tubes, recordings ~rolling off 80-100 Hz, not a bad choice, but would at least need to make the cab somewhat aperiodic for nowadays and forget 80 L vent tuned for bass.
GM
Today i had sometime to work on them. I removed all the unnecessary drivers and kept only the AD1255 then sealed the holes using one of my daughters drawings which was done on a hard wooden cake board. Then rewired the speakers using new wires and closed the box properly. Now the bass port is at the bottom, speakers at the top of the boxes. I see a significant improvement in sound quality, especially bass.
Attachments
ahh the ever so typical construction of the era with little to no bracing...your bass performance could be improved further with a few holey braces or even some1x2 on edge glued to the sides.
Here is a video after I have finished setting them up. I think they sound pretty good, They do have more than enough bass for me...! but stuff like "Miles Davis - So what" opening drumming could use a bit more of that type of bass.
Have a look,
Philips AD1255/M7 Vintage Speaker on Technics SU-7700ii - YouTube
Have a look,
Philips AD1255/M7 Vintage Speaker on Technics SU-7700ii - YouTube
I am sorry, I am not an expert on this. I am gonna google up what's bracing and holey braces, 🙂
sorry i guess that warrants further explanation, the braces are simply a means of preventing the enclosure from resonating by connecting panels, the "holey" part is just that as well holes in the connecting panels so as to not form a solid partition to allow the driver to breath or change the volume of the box.
have you used any damping in the box?(from what i hear in the YouTube vid i'd say, no.)
have you used any damping in the box?(from what i hear in the YouTube vid i'd say, no.)
The Interior of the box is being lined with some kind of fluffy fabric which has been aged very badly. There were some super old cotton inside and pasted on certain parts of the walls. Should I clean them up and paste new synthetic wool or maybe sponge?
Yes, I got what it means by braces, Most likely I will add them with help from a speaker builder.
I think I can do the damping part.
i have a pair too ad 1255/m7s i am english but live in netherlands as far as enclosures there were some designed by philips that are in a speaker building book different designs for ad9710 also good 8 inch full range speakers for 10 watts the designs in the books are for earlier ad 5200s and the ad 1255 and ad 1256 were updated versions of the 5200s some tube guys here like them in open baffles but bass is compromised a bit but it does allow them to reach maximum efficiency i see somebody here measured his speakers that are of course old and came with 183 litres for a sealed box but the original specs is 218 litres now in 1 meter high x40 x40cm labarynth cabinets whereas when i bought them theywere in cabinets about 40x20x60 cm sealed boxes and they sounded great my labaryth cabinets a soort of transmission line are difficult to get the bass right so i am planning to go all the way soon and build the big sealed boxes.all i know is the more air these things have the more you exploit their high efficiency. which is why open baffles sound very nice too.