seek recommendation for lack of bass from my Advents - AVS Forum
Speakers > seek recommendation for lack of bass from my Advents
HalPri's Avatar HalPri 02:33 AM 05-11-2013
I have a pair of Advent 5012s, basically the third version of the large Advent speaker, from maybe the late 1970s. The midrange is great. The treble is a little thin. The bass is pretty weak. What can I do to improve the situation?

The Advents were refoamed recently, by an expert. They are on the floor, and in front of a fairly thick rug. The system is in my living room, which is maybe 12 x 20. With the rug, the couch, and curtains, it's a fairly sound-absorbent space. I mainly watch movies, but also listen to CDs. I like classical, jazz, and classic rock. I want better bass in my music. I don't watch action movies, and I don't care about movie sound effects. I listen at moderate volumes. I live on a busy street, with some street noise.

The Advents are driven by a Marantz NR1403, a 5.1 AVR with 50w per channel at 8 ohms. Having AM/FM is nice, but not required. Only the two Advents are connected. I have no plans or desire to add surround speakers. I like the convenient HDMI switching on the AVR, but it's not required. The source is an Oppo BDP-103 BluRay player. I have fiddled around with the various sound options on the Marantz, including just turning up the bass. It just doesn't sound all that great. I have also moved the speakers around, including pushing them back against the wall.

I'm willing to spend say around $500. Options include a) opening up the Advents and replacing the capacitors, b) replacing the Advents, c) buying a subwoofer, d) buying a power amplifier and using the Marantz as a preamp only, or e) replacing the Marantz with another AVR, a preamp + amp, an integrated amp, or a stereo receiver. If I replaced the Advents, I could get maybe $200 for them. If I replaced the Marantz, I could also get probably $200. So you can figure in the extra 200 in those cases.

What would you recommend?

RicardoJoa's Avatar RicardoJoa 04:39 AM 05-11-2013
i would check polarity both outside and inside.
HalPri's Avatar HalPri 09:46 AM 05-11-2013
Quote:
Originally Posted by RicardoJoa View Post

i would check polarity both outside and inside.
Sorry, I forgot to mention that I have an audio demo disc with the usual in-phase/out-of-phase track, and my speakers are clearly in phase.

I assume that's what you are referring to by "polarity". But I don't understand "outside and inside". I will try reversing the connections on both speakers, just in case that's what you mean.
RicardoJoa's Avatar RicardoJoa 10:56 AM 05-11-2013
Quote:
Originally Posted by HalPri View Post

Sorry, I forgot to mention that I have an audio demo disc with the usual in-phase/out-of-phase track, and my speakers are clearly in phase.

I assume that's what you are referring to by "polarity". But I don't understand "outside and inside". I will try reversing the connections on both speakers, just in case that's what you mean.

Polarity and phase are two different things though people get mess with it. What i mean is to check the plus and minus of the speaker cable are going to the right terminals on the amp. You mentioned that the woofer were refoam, assuming an expert, hopefully that the terminals inside the cabinet from the xover to the woofer are not reversed. Also, check if the foam are all the way sealed correctly and that the port from inside are not block.
Bill Fitzmaurice's Avatar Bill Fitzmaurice 01:02 PM 05-11-2013
Quote:
Originally Posted by HalPri View Post

What would you recommend?
Invest in one of these and freeware room response measuring software, like REW:
http://www.parts-express.com/pe/showdetl.cfm?partnumber=390-808

With them you can first make sure if anything is broken before you try to fix it, and if it is broken you can successfully fix it by knowing exactly what you're hearing rather than relying on guesswork.
RicardoJoa's Avatar RicardoJoa 01:12 PM 05-11-2013
Thats a good advice from Bill, but i would at least do the general stuff before spending any money.
HalPri's Avatar HalPri 06:24 PM 05-11-2013
I pulled off the grills and checked the refoam job. It looks great. I poked around all of the glued places; there is no gap. I ran the Audyssey setup in the Marantz, using the microphone that came with it. It didn't complain about polarity. The system sounded about the same afterwards.

I didn't mention that I recently changed the speakers. I had Advent/2s, and upgraded to these Advent 5012s. The new speakers sounds a lot better, except for the bass. Or at least that's what I think now. Maybe both speakers were normal, and I'm misremembering the old ones. I guess that's why people measure.

I think I will try borrowing (or buying, from a place that will let me send them back) either a subwoofer or some more modern speakers, just to be able to compare in my own room.

Thanks for all the advice!
donutfan's Avatar donutfan 06:49 PM 05-11-2013
Advents, especially those Advents, are known for producing prodigious amounts of bass (for their size). So IMO something isn't right. And IIRC the electrical characteristics of electrolytic caps older than around 20 years can begin to change, and what usually happens is the output from a tweeter (or midrange) can be significantly reduced.
sivadselim's Avatar sivadselim 11:21 AM 05-12-2013
Quote:
Originally Posted by HalPri View Post

The Advents are driven by a Marantz NR1403, a 5.1 AVR with 50w per channel at 8 ohms. Only the two Advents are connected.

Your AVR is correctly configured as having only 2 speakers connected, right?
lovinthehd's Avatar lovinthehd 11:34 AM 05-12-2013
Having had original Advents (but not familiar with this particular iteration), if I had known about subs back then (early 70s) I would have added one. Nice bass, but not like having a sub. So you never heard these speakers before refoaming? Why are they on the floor? You listen on the floor?
HalPri's Avatar HalPri 03:40 PM 05-12-2013
Quote:
Originally Posted by sivadselim View Post

Your AVR is correctly configured as having only 2 speakers connected, right?

Correct.
HalPri's Avatar HalPri 03:49 PM 05-12-2013
Quote:
Originally Posted by lovinthehd View Post

Having had original Advents (but not familiar with this particular iteration), if I had known about subs back then (early 70s) I would have added one. Nice bass, but not like having a sub. So you never heard these speakers before refoaming? Why are they on the floor? You listen on the floor?

Before refoaming, the foam was about 50% rotted away. I heard them, but they didn't sound like much.

They are on the floor because they are quite big, and I have no convenient place up higher. However, I should try putting them up on chairs, say, just to check the difference.

I had several friends with large Advents in the 70s. I recall them as having great bass. But time distorts all memories; perhaps the bass was strong by 70s standards, but these days, when subs are everywhere, maybe vintage speakers are like what I'm hearing.
HalPri's Avatar HalPri 03:56 PM 05-12-2013
Quote:
Originally Posted by donutfan View Post

Advents, especially those Advents, are known for producing prodigious amounts of bass (for their size). So IMO something isn't right. And IIRC the electrical characteristics of electrolytic caps older than around 20 years can begin to change, and what usually happens is the output from a tweeter (or midrange) can be significantly reduced.

I could open them up and check the components. But if something had failed, I would hear a difference in the speakers, I'm thinking. Since I don't, I'm either expecting too much, or it's the refoam job, or my AVR is misconfigured (which seems very unlikely; it displays the configuration, and I tried several different sound settings) or suboptimal (a Marantz? also seems unlikely).
lovinthehd's Avatar lovinthehd 04:15 PM 05-12-2013
The refoam job was done with the original spec foam or? Could be an influence I suppose.
HalPri's Avatar HalPri 08:51 AM 05-24-2013
Here's an update on the Advent bass. I opened up the speakers to check them out. I have a multimeter that measures capacitance and inductance (and resistance and current and voltage). I saw from the schematic that I could measure the components in place if I just detached a wire from each speaker, breaking all loops in the circuit. The components were all at spec.

I checked the batting in the speaker. It was polyfill, so had been added recently (since the original material would have been different, maybe fiberglass). The speakers were about 75% full, but there was enough space to theoretically have some resonance. So I went to Walmart and bought more polyfill (for about $4), and stuffed it in there.

Then I checked the relative polarity of woofer and tweeter. The woofers have paint on the terminals, one black and one red, so it's obvious how to connect the black and red wires. However, the tweeters are completely symmetric, and there is no indication which side is which. (Actually this isn't quite true. Part of the tweeter has a yellow tag on it, and the wires are black and yellow, so you might think that the yellow wire goes near the yellow tag. The problem is that the part with the yellow tag can be removed and rotated around, so that the yellow tag can in fact be next to whichever terminal you want. I don't believe that rotating that part, the magnet, changes the polarity, which I suspect is determined by the direction of the winding inside the part that doesn't rotate. But I could be wrong.) So I listened to each speaker with different polarities on the tweeter, to see which sounded best. You might think this would be an easy task, since it's easy to distinguish reversed and correct polarity between two speakers. But detecting it between woofer and tweeter was very difficult, and I have no idea if I connected them correctly. Both positions sounded about the same.

Anyway, after all this, the result sounded pretty good. There's definitely more bass, or perhaps I have convinced myself that all my efforts must have had some good result, and I am imagining more bass. But the nice thing about speakers is that this distinction doesn't matter!

Thanks again for the tips.
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