delta 10's replacements in Portabass 2x10?

[Wes Whitmore]

The BP102's have a recommended enclosure volume that you might be able to use. You can do sealed or ported in 2ft3.

[Invalid or Expired Link Removed]

 

[danomite64]

Frequency response and all the T/S specs that determine how a driver works are what matters.

I found these specs, which are what Ampeg published.

Features:
High frequency variable "L-Pad" control

1/4 in. & Neutrik Speakon connectors

Lightweight Italian Poplar plywood design

Removable telescoping dolly-style handle with wheels
Technical Info
Dimensions: 24 x 15 x 15.5 in.

Weight: 32 lbs.

Component 1: Size: 2 x 10 in.
Component 2: Size: Compression Driver

Component 2: Voice Coil: 1 in.
Component 1: Voice Coil: 2 in.

Component 1: Neodymium Magnet Weight: 4 oz.
Component 2: Magnet Weight: 4.7 oz.

RMS Handling: 400 watts

Program Handling: 600 watts

Crossover Frequency: 3.5 kHz

Frequency Response (-3dB): 40 Hz - 20 kHz

Sensitivity: 93 dB

Nominal Impedance: 4 ohms

 

[billfitzmaurice]

I found these specs, which are what Ampeg published.

Features:
High frequency variable "L-Pad" control

1/4 in. & Neutrik Speakon connectors

Lightweight Italian Poplar plywood design

Removable telescoping dolly-style handle with wheels
Technical Info
Dimensions: 24 x 15 x 15.5 in.

Weight: 32 lbs.

Component 1: Size: 2 x 10 in.
Component 2: Size: Compression Driver

Component 2: Voice Coil: 1 in.
Component 1: Voice Coil: 2 in.

Component 1: Neodymium Magnet Weight: 4 oz.
Component 2: Magnet Weight: 4.7 oz.

RMS Handling: 400 watts

Program Handling: 600 watts

Crossover Frequency: 3.5 kHz

Frequency Response (-3dB): 40 Hz - 20 kHz

Sensitivity: 93 dB

Nominal Impedance: 4 ohms

Nothing there is of any value. This is what a driver spec sheet looks like:
[Invalid or Expired Link Removed]

Speaker manufacturers don't provide useful data. The driver manufacturer should, if you have the driver model number.

 

[danomite64]

I emailed AuraSound to see if they'd give me that sheet.

 

[AlexanderB]

bill said:

Frequency response and all the T/S specs that determine how a driver works are what matters.

Mids are not detemined by the T/S parameters, as long as one considers "mids" as something over 200-300Hz. A frequency plot will also not reveal the level (and characteristics) of the distorsion generated by the speaker.
Especially since T/S parameters are "small signal" data, which are not applicable to high SPL.

A driver for such wide band and high SPL applications as bass cabinets covering 50 to 3000 Hz at 110 dB will definately have its performance affected by vented/solid core, extended or flat pole piece, (w/w.o shorting ring?), suspension material and geometry, under hang / over hung coil, dust cap material and size, cone profile, cone material etc etc.

You know that these things matter, Bill - why say that they do not?

 

[danomite64]

Hey, if you piss off Bill to the point he no longer wants to help me, I'm gonna tell all your friends you're a closet bagpipe player!

 

[AlexanderB]

But seriously, what he is saying is sort of the loudspeaker analogy to " pick up placement is the only relevant factor to the tone of an instrument".

It is a major influence, yes, but other factors will also contribute to the total result.

The same goes for speakers; T/S parameters and a response chart says a lot but certainly not all. To me it does not matter who says something wrong (even Bill), if it is not correct, it is not correct.

In all his experience I often see Bill using these very "digital" yes/no, good/bad, right/wrong answers to many different loudspeaker related discussions. "Rule of thumb" and "over simplification" are not beneficial to anyone and will not help those persons trying to better understand how things work.

/Alexander

 

[danomite64]

That's cool, even if most of it's going over my head. I took out a speaker to see if it had a model #, and its 86-024-08. Then I emailed tech support for Aurasound and Ampeg (LOUD) to see if either of them have the spec sheet.

 

[danomite64]

Okay, the dude from Aurasound said "Thanks for your mail. That 10” bass speaker we did for Ampeg is from 2001-2002 era. I don’t have an official spec document for the model but do have this test data." He sent me a text file and 2 pdf's:

NS10-495-8A 11121D #1


"Title: Measured Parameters"
"Method: Mass-loaded (50.000 grams)"
"DCR mode: Measure (-0.08 ohms)"
"Area (Sd): 346.36 sq cm"
"Series resistance: 75.00 ohms"
"Stimulus level: 1.00 volts"
0.288 "RMSE-free Ohms"
53.485 "Fs Hz"
5.963 "Re Ohms[dc]"
99.460 "Res Ohms"
15.892 "Qms "
0.953 "Qes "
0.899 "Qts "
0.671 "L1 mH"
0.873 "L2 mH"
3.981 "R2 Ohms"
0.232 "RMSE-load Ohms"
42.505 "Vas(Sd) liters"
35.100 "Mms grams"
252.271 "Cms æM/Newton"
8.592 "Bl Tesla-M"
91.447 "SPLref(Sd) dB "
0.003 "Rub-index "

 

[billfitzmaurice]

Good news and bad news. If you want something with higher sensitivity in the mids and highs you can get it with just about any decent ten. The bad news is that the Aura has a substantial midbass peak centered at 90 Hz, which you'll lose with a different driver, so it will sound thinner. But it's only a 3dB loss, one you could probably live with. I'd load it with Eminence Basslite S2010 if you want to keep the price down, they run about 3dB hotter. If you want really strong mids the Deltalite II 2510s have mids in spades. If the low end is lacking you'll have to add a port.

 

[danomite64]

Well, I'll probably go with the Deltalites, in case I end up finding a Portabass 800 head somewhere down the line. As for ports, I remember reading a post about what ports would work with this cab:

If you own one of these Ampeg PB210H enclosures and can no longer get blown drivers replaced because they're out of warranty, I have a suggestion...

Replace them with Eminence Legend BP102 drivers. You can buy them almost anywhere for about $75.

Eminence Customer Service was very helpful and provided me with porting information. The PB210H needs two ports with a inside diameter of 2 7/8" by 3 7/8" long.

I got my ports from partsexpress.com The ones that I purchased are listed as 2 7/8" X 5". You'll need to cut them down carfully because they're slightly tapered. I cut mine on a table saw with a crosscut jig, using shims to hold them square to the blade.

If you're not handy with a table saw, I'd suggest placing masking tape on them and drawing your cut line on the tape. Then cut them with a hack saw.

Due to the fact that they were tapered, and the I.D. is actually 2 3/4" and not 2 7/8" at the baffle and approximately 2 5/8" at the cut end I reduced the length of the port to 3" even.

The port length for a 2 3/4" I.D. was 3 3/8". The port length got shortened 3/8" for every 1/8" less of inside diameter. This is how I arrived at the 3" port length.

The holes for the ports can go in the upper and lower corners on the same side of the baffle as the tweeter. A 3" hole saw works fine. Be carful to locate exactly where the hole is drilled; there's not much room to spare. These ports barely fit. Glue them in place.

The enclosure/speakers now handle 350 watts as compared to about 200 watts with the enclosure not ported.

Also, the enclosure is now tuned to 50Hz with these ports as compared to about 70Hz without porting it.

F3 = 52Hz.

The above specifications came from Eminence based on precise enclosure volume calculations that I gave to them.

I don't believe that Ampeg's specifications for frequency range or power handling were ever very accurate. The enclosure does still sound good though, as long as you don't need to get too loud. I use mine with a Mesa Walkabout. It's no surprise that the Ampeg PB250 head was only 250 watts.

The enclosure still has it's punchy tone, but now has more bottom end. It sounds great! I'm sure that these drivers will be much more reliable than the OEM drivers as well.

He used different speakers, though. And, I'm not sure I'll be wanting too much low end, as the room tends to make it's own.

 

[AlexanderB]

The Deltalite II 2510 has a strong rise in the output in the upper mids, just like Bill says. For some users and styles, that peak is very useful, for others it is not.
Incidentally, the rising slope of the response (wording?) is about 6 dB per octave. I added an inductor (which yields an output decrease of 6dB per octave) in series, effectively turning that peak into an almost flat output. I am very happy with that result and such a solution is very easy to A/B test and it also cost rather little.

An idea for a more flexible cab:
Some Trace Elliot speakers have bass reflex ports with "end plugs", letting you tune the output of the cabinet to better suit room acoustics etc. Blocking the port will turn your bass reflex box into a sealed one. I think this is a neat trick and it can be very useful once you have become familiar with the different characteristics of a sealed and a reflex cabinet.

 

[AlexanderB]

I recommend you download WINISD and at least briefly check what comes out of it when you play around with the Deltalites and a bass reflex port.